WO2025099493A1 - Flexible circuit structure and smart wearing arrangement with such a flexible circuit structure - Google Patents

Abstract

In some aspects, a flexible circuit structure is provided, comprising a carrier of a flexible insulating material, conductive tracks and one or more electrodes formed on at least one of a first surface of the carrier and a second surface of the carrier opposite the first surface, and connection terminals formed on the first surface and electrically coupling to the electrodes via at least some of the conductive tracks. The flexible circuit substrate further comprises a fluid collector system formed on the carrier with the fluid collector system comprising at least one microchannel formed in the second surface. Herein, at least one of the conductive tracks is formed so as to at least partially extend within the at least one microchannel. This flexible circuit structure may be used in a wearing arrangement, such as a bandage, or as a transducer of a biosensor.

Description

Flexible Circuit Structure and Smart Wearing Arrangement with such a Flexible Circuit Structure Field of the Disclosure The present disclosure relates to a flexible circuit structure and a smart wearing arrangement_{with such a flexible circuit structure, such as a smart bandage with such a flexible circuit} structure. Technological Background A wide variety of portable or wearable devices with flexible circuits are known, for tracking steps, GPS location, heart rate and a variety of additional biometric parameters to be monitored for health reasons and medical purposes. In the area of medicine, it is of particular interest to monitor the state of tissues, organs or systems to be treated, the more so if such information is gathered in real time during treatment. Many types of treatments are still routinely performed without the use of sensor data collection, instead, such treatments rely upon visual inspection by a caregiver or other limited means_{rather than collected sensor data. For example, in the case of wound treatments via dressings} or negative pressure wound therapy, data collection is generally limited to visual inspection by a caregiver and often the underlying wounded tissue may be obscured by bandages or other visual impediments. Even intact, unwounded skin may have underlying damage that is not visible to the naked eye, such as a compromised vascular or deep tissue damage that may lead to an ulcer. Similar to wound treatment, only limited information is gathered on the underlying tissue during orthopedic treatments requiring the immobilization of a limb with a cast or other encasement. In instances of internal tissue repair, such as a bone plate, continued direct sensor driven data collection is not performed._{Furthermore, braces or sleeves used to support musculoskeletal function do not monitor the} functions of the underlying muscles or the movement of the limbs. Outside of direct treatment, common hospital room items, such as beds and blankets, could be improved by adding the_{capability to monitor patient parameters.} A smart bandage allows improved monitoring of a wounds healing process by better controlling the wound characteristics. For a specific wound, the applied bandage should be tight in order to improve the blood flow. For example, by monitoring the pressure applied on the bandage and orthesis, a caregiver is able to decide whether it is necessary to provide a new bandage or to avoid changing the bandage when it is not necessary._{It is often necessary to adjust wearable devices to the shape of the body part on which the} device is to be located in order to avoid discomfort or irritation of the respective body part._{Therefore, it may be desirable to provide a flexible circuit structure for a smart wearing} arrangement and a smart wearing arrangement in which users discomfort is minimized, if not avoided all together, due to the presence of the sensor system, and wherein fabrication of such a sensor system and smart wearing arrangement is optimized. An adhesive bandage, also called a sticking plaster, medical plaster, or simply plaster in British_{English, is a small medical dressing used for injuries not serious enough to require a full-sizebandage. The adhesive bandage protects a wound and scab from friction, bacteria, damage,and dirt, thereby avoiding disturbance of the healing process of the body. Some dressings mayhave antiseptic properties. Additionally, an adhesive bandage holds two cut ends of skin at awound together to make the healing process faster. Conventionally, an adhesive bandage is a} small, flexible sheet of material which is sticky on one side, with a smaller, non-sticky, absorbent pad stuck to the sticky side. The pad is placed against the wound, and overlapping edges of the sticky material are smoothed down so they stick to the surrounding skin. Adhesive_{bandages are generally packaged in a sealed, sterile bag, with a backing covering the stickyside and the backing is removed as the bandage is applied. They come in a variety of sizesand shapes. The backing and bag are often made of coated paper, but may be made of plastic,while the adhesive sheet is usually a woven fabric, plastic (PVC, polyethylene or polyurethane),or latex strip. It may or may not be waterproof; if it is airtight, the bandage is an occlusivedressing. The adhesive is commonly an acrylate, including methacrylates and epoxydiacrylates (which are also known as vinyl resins). The absorbent pad is often made of cotton,} and there is sometimes a thin, porous-polymer coating over the pad, to keep it from sticking to the wound. The pad may also be medicated with an antiseptic solution. In some bandages, the pad is made of a water-absorbing hydrogel. This is especially common in dressings used on blisters, as the gel acts as a cushion. As another example of a wearing arrangement in medical application, an elastic bandage is_{known, representing a "stretchable bandage used to create localized pressure". Elasticbandages may be used to treat muscle sprains and strains by reducing the flow of blood to aparticular area by the application of even stable pressure which may restrict swelling at theplace of injury or to treat bone fractures. Padding is applied to the fractured limb, then a splint} (usually plaster) is applied. The elastic bandage is then applied to hold the splint in place and to protect it. This is a common technique for fractures which may swell, which would cause a cast to function improperly. These types of splints are usually removed after swelling has_{decreased and then a fiberglass or plaster cast may be applied.Due to the risk of latex allergies among users, the original composition of elastic bandages haschanged. While some bandages are still manufactured with latex, many woven and knitted} elastic bandages provide adequate compression without the use of natural rubber or latex. The_{modern elastic bandage is constructed from cotton, polyester and latex-free elastic yarns. By} varying the ratio of cotton, polyester, and the elastic yarns within a bandage, manufacturers are able to offer various grades of compression and durability in their wraps. Often aluminum or stretchable clips are used to fasten the bandage in place once it has been wrapped around_{the injury. Some elastic bandages even use Velcro closures to secure and stabilize the wrap} in place._{Aside from use in sports medicine and by orthopedists, elastic bandages may be used in thetreatment of lymphedema and other venous conditions. However, some compression wraps} are inadequate for the treatment of lymphedema or chronic venous insufficiency. They provide a high resting compression and low active compression. A more appropriate use for compression in treating lymphedema or other edema conditions would be TG shapes, tensoshapes, compression socks or compression wraps for acute conditions or exacerbation. Physical therapists and occupational therapists have special training and certifications to apply_{appropriate compression wraps for edema and lymphedema. Elastic bandages may also beused for weight loss when applied as a body wrap and rehabilitating injured animals through} veterinary medicine. Chronic non-healing wounds are one of the major and rapidly growing clinical complications all over the world. Current therapies frequently include emergent surgical interventions, while_{abuse and misapplication of therapeutic drugs may lead to an increased morbidity and} mortality rate. Despite the urgent need for more effective, controllable, biocompatible, and_{easy-to-implement therapies with minimal side effects, conventional wound care devices haveremained passive and cannot dynamically respond to variations in wounds’ physiological} microenvironment. Further, existing wound treatment may be a manual process that requires assessing the wound, monitoring the wound’s physiological characteristics, applying a bandage to the wound if needed, and treating the wound for infection. In addition, current wound care products are unable to provide information about the wound, such as status of the wound bed or wound healing rate over time. These steps are typically performed in a medical facility by a medical provider and generally require a patient to visit the facility to have general wound care and management conducted. However, there are many situations where receiving such treatment is difficult or impossible,_{for example, on the battlefield, in space, in developing or low- or middle-income countries, or} during a global pandemic. Therefore, a system and method of dynamically treating wounds when outside of a medical facility, which allows for more constant, individualized care, monitoring, and treatment, may be desirable. It is desirably to provide a flexible circuit structure for a smart wearing arrangement and a smart wearing arrangement including such a flexible circuit structure of a compact layout and/or with improved reliability._{Summary of the DisclosureThe drawbacks of the state of the art are overcome by means of a flexible circuit structure asdefined in independent claim 1 and a method as defined in claim 23. Advantageousembodiments are defined in the dependent claims.According to a first aspect of the present disclosure, a flexible circuit structure is provided.In illustrative embodiments of the first aspect, the flexible circuit structure comprises a carrier} of a flexible insulating material, preferably a carrier strip, conductive tracks and one or more electrodes formed on at least one of a first surface of the carrier and a second surface of the carrier opposite the first surface, and connection terminals formed on the first surface and electrically coupling to the electrodes via at least some of the conductive tracks. The flexible circuit structure further comprises a fluid collector system formed on the carrier, the fluid collector system comprising at least one microchannel formed in the second surface. At least_{one of the conductive tracks is formed so as to at least partially extend within the at least onemicrochannel. The microchannels may provide for pathways that guide a fluid to one or morededicated (or corresponding) conductive tracks of the conductive tracks, thereby allowing a} dedicated sensing function implemented by these conductive tracks. For example, the_{microchannels may be part of or represent a microfluidic system formed on the carrier, the} microfluidic system comprising the microchannels for implementing tiny channels, reservoirs,_{valves, and sensors with the function of controlling fluids in confined spaces on the carrier} when employing the flexible circuit structure in fluid detection applications. The microchannels represent an illustrative example of a microfluidic technology implemented on the carrier. For example, the microfluidic system may be provided on the carrier by laminating a layer (e.g., PET) onto at least a portion of a surface of the carrier and patterning the laminated layer into a line pattern to define the microfluidic system on the surface of the carrier such that one or more microchannels are defined in or on the surface of the carrier, wherein the microchannels are formed by a laminated layer pattern or laminated line pattern on the surface of the carrier (e.g., PET and an adhesive or other bonding of PET on the carrier after/for lamination). Within at least one microchannel, a transducer of a biosensor may be provided, e.g., at least one electrode of the transducer being formed within at least one microchannel, e.g., by at least partially routing an electrically conductive material in the at least one microchannel and forming an electrode at a routed line within the at least one channel, possibly arranging a bioreception_{material, such as a membrane material, on the electrode (e.g., cross linking the bioreception} material on the electrode), for the example the electrode being a noble metal electrode such as a gold electrode. In some further illustrative example herein, the at least one microchannel_{may be covered by a covering system at the electrode such that a cavity around the electrode} for receiving a biofluid subject to detection is formed at least at the location of the electrode(s). The person skilled in the art will appreciate that, when combining and/or equipping the flexible_{circuit structure with electrochemical sensor electrodes, easy scalable biosensors may be} manufactured with higher throughput, lower cost, and the ability to address more complex and specific technical objects._{Alternatively, the flexible circuit structure of the illustrative embodiments of the first aspect,} comprises a carrier of a flexible insulating material, preferably a carrier strip, conductive tracks and one or more electrodes formed on at least one of a first surface of the carrier and a second surface of the carrier opposite the first surface, and connection terminals formed on the first surface and electrically coupling to the electrodes via at least some of the conductive tracks. The flexible circuit structure further comprises an electric module having a microchip, the_{electric module being releasably coupled to the connection terminals, and an LED componentarranged on the first surface, the LED component connected to two or more of the connection} terminals by conductive tracks routed on the first surface between the LED component and the_{two or more connection terminals. Herein, the two connection terminals in contact with the LED} component are not interconnected such that an open circuit is provided with respect to the LED component and the conductive tracks routed between the LED component and the two connection terminals, the open circuit being closed by the electric module coupled to the_{connection terminals. The LED component indicates a status of connection of the electric} module with the conductive tracks on the carrier, particularly whether the electric module is properly connected with the carrier because only when establishing a proper electrical connection of the electric module with the conductive tracks on the carrier, a closed circuit on the carrier between LED and electric module is established, indicating proper connection when_{the LED signals electrical connection. The electrical function of the electrical module is notdepending on the function of the LED. In other words, the LED acts as an indication of correct} connection and not actively participating in the function of the electrical module, e.g., not_{participating in wound healing or detection function provided by the electrical module.} In some applications of the first aspect, the flexible circuit structure of the first aspect may be configured for use in a wearing arrangement, such as a bandage, or in a transducer of a biosensor. In accordance with the illustrative embodiments of the first aspect, the carrier may_{be a printed circuit board (PCB) or may not be a PCT but connected to a PCB, where optionallythe PCB comprises a power source (e.g., a battery) and/or a microchip and/or means for} enabling wireless communication with the one or more electrodes. Accordingly, the flexible circuit structure of the first aspect allows a versatile implementation in_{a vast range of applications without being bound by the carrier being limited to a PCB type} structure and/or material. It is easy and cost efficient to manufacture the flexible circuit structure for wearable arrangements, such as bandages, e.g., smart bandages, which may be releasably connectable with a module e.g. comprising microelectronic elements, such as microprocessor devices for electrically and electronically operating the one or more electrodes, and/or antenna elements, optionally antenna circuit elements and/or antenna driving elements which are used and configured, respectively, for operating one or more antenna elements (which antenna elements may be optionally formed on the carrier or on a module to be releasably connected to the carrier via the connection terminals). Accordingly, the carrier may_{be designed in a compact way with great flexibility (with respect to function and/or its} mechanical characteristic) by comprising terminals enabling releasably connecting the flexible circuit structure to separate electric and/or electronic elements such that the flexible circuit structure may be employed in a modular arrangement or system. Herein, the carrier may be, without limitation, provided as a flat carrier element having two main surfaces which are arranged opposite of each other, e.g., the first surface and the second_{surface. This means that the first and second surfaces are greater than any other surface of} the carrier, a dimension normal to the first surface measuring a thickness of the carrier, i.e., a dimension extending between the first surface and the second surface in the carrier. Two_{orthogonal dimension of the first surface and/or the second surface may be a width of the} carrier and a length of the carrier, the length being greater than the width. An aspect ratio from thickness to width is generally smaller than 1, for example, smaller than 0.5 or 0.1 or 0.01 or 0.001._{Herein, a bandage may be understood as comprising a piece of material used either to supporta medical device such as a dressing or splint, or on its own to provide support the movement} of a part of the body, wherein the carrier may be the piece of material. When used with a_{dressing in addition to the carrier, the dressing may be applied directly on a wound, thebandage being used to hold the dressing in place. Other bandages may be used without} dressings, such as elastic bandages that are used to reduce swelling or provide support to a_{sprained ankle. Tight bandages may be used to slow blood flow to an extremity, such as when} a leg or arm is bleeding heavily, one or more electrodes being configured so as to implement at least one pressure sensor element for allowing pressure monitoring in the bandage, for_{example. In some special but non-limiting example, the carrier may be an adhesive bandage} having an adhesive material or layer formed at least partially on the first and/or second surface, wherein the one or more electrodes may be only formed on the first surface or the second_{surface. In still some other alternatives herein, a plurality of electrodes may be provided,} wherein or some electrodes being formed on the first surface, while some other electrodes are formed on the second surface, preferably in one or more surface regions of the second surface not having the adhesive material or layer formed thereon. For example, when the one or more electrodes are formed only on the first surface, the adhesive material or layer may be at least partially formed only on the second surface. Alternatively, when the one or more electrodes are formed at least partially on the first surface and at least one of the electrodes formed on the first surface is to be brought into contact with a skin of a user to which the flexible circuit structure is to be applied, one or more surface regions, preferably free of conductive tracks and connection terminals, are provided with adhesive material or layer formed thereon adjacent to the at least one of the electrode(s), the carrier being twisted such that the one or more surface regions and the at least one of the electrode(s) is brought into contact with the skin of the user, while the terminals are arranged opposite the one or more surface regions, i.e., without contact to the skin of the user. In some illustrative embodiments of the first aspect, wherein the carrier may comprise a_{substrate. For example, the substrate may be made of PET and/or PI and/or VEP and/or FET(fluorated ethylenpropylen), laminated with a conductive material sheet. The conductivematerial sheet may be patterned, e.g., by etching or cutting or punching etc., into a routingpattern, the routing pattern providing the conductive tracks. The flexible circuit structure maycomprise at least two electrodes. The at least two electrodes may be configured as electrodesadapted to performing one of electrochemistry measurement and chemiresistive} measurement. Alternatively, the at least two electrodes may be configured as electrodes_{adapted as electrodes comprising an organic electrochemical transistor system.For example, electrochemical electrodes may be electrodes that convert chemical data, e.g.,} concentration of a single sample component, into an analytically usable electrical signal, .e.g, a faraday voltage or faraday current at terminals of the electrodes. Accordingly, the flexible_{substrate comprising such electrodes may implement or allow to implement a physicochemicaltransducer of a chemical sensor having the electrodes acting as receptors that are variable} and can range from activated or doped surfaces to complex (macro)molecules that create_{highly specific interactions with an analyte. As electrochemical sensors may be characterized} according to the following classes: amperometric, potentiometric, impedimetric, photoelectrochemical, and electrogenerated chemiluminescence, the electrodes of these sensors and the implementation of electronic modules and components on or coupled to the flexible circuit structure. For example, for potentiometric sensors, electrodes are provided_{configured for allowing a specific sensor–analyte interaction where a local Nernstianequilibrium is formed at the electrode interface(s) when no current is allowed to flow, givinginformation about an analyte’s concentration. For example, electrodes of amperometric} sensors employ a voltage placed between a reference electrode and a working electrode to initiate electrochemical oxidation or reduction, measuring the resulting current as a quantitative_{indicator of the analyte’s concentration (via the Cottrell equation). For examples, electrodes ofconductometric sensors (frequently referred to as impedimetric sensors) are configured formeasuring changes in surface impedance to detect and quantify analyte-specific recognitionevents on the electrode(s). The person skilled in the art will appreciate that the electrodes may} be accordingly adapted for implementing an electrochemical sensing function._{For example, chemiresistor adapted electrodes may be electrodes comprising a material that} changes its electrical resistance in response to changes in the nearby chemical environment._{Such chemiresistors allow to implement a class of chemical sensors that rely on direct} chemical interaction between sensing material and analyte. For example, the sensing material and the analyte can interact by covalent bonding, hydrogen bonding, or molecular recognition._{As there are several different materials having chemiresistor properties, such as} semiconducting metal oxides, some conductive polymers, and nanomaterials like graphene, carbon nanotubes and nanoparticles, there are different possibilities for providing_{chemiresistor-measuring electrodes, e.g.,. applicable as selective sensors in devices likeelectronic tongues or electronic noses. For example, electrodes adapted to chemiresistormeasurements may comprise a sensing material that bridges a gap between two electrodes} or coats electrodes such as electrodes provided as a set of interdigitated electrodes. Upon measuring the resistance between the electrodes, chemiresistive measurements may be performed as the sensing material has an inherent resistance that can be modulated by the presence or absence of analyte. During exposure, analytes interact with the sensing material and these interactions cause changes in the resistance reading. In some applications,_{resistance changes may simply indicate the presence of analyte, while in others, the resistance} changes may be measured by value to determine the amount of analyte present when_{resistance changes are related, e.g., proportional, to the amount of analyte present, therebyallowing for the amount of analyte present to be measured.With respect to an organic electrochemical transistor, the electrodes may be provided aselements of an organic electronic device which functions like a transistor such that current} flowing through the device is controlled by the exchange of ions between an electrolyte and a channel of the organic electrochemical transistor (with the channel being composed of an_{organic conductor or semiconductor). Accordingly, the carrier may comprise an organic} electrochemical transistor having source and drain acting as electrodes, this transistor being formed of the channel formed on the carrier. During operation, the exchange of ions is driven_{by a voltage applied to a gate electrode of the organic electrochemical transistor, the gateelectrode being in ionic contact with the channel through the electrolyte. The migration of ions} between the channel and the electrolyte is accompanied by electrochemical redox reactions_{occurring in the channel material such that electrochemical redox of the channel along with ion} migration changes the conductivity of the channel in a process called electrochemical doping. Flexible circuit structures including organic electrochemical transistors are configured for applications in biosensors, bioelectronics and large-area, low-cost electronics. Such flexbile_{circuit structures may also be used as or in multi-bit memory devices that mimic the synapticfunctionalities of the brain with possible application to elements in neuromorphic computing} applications. In some illustrative examples herein, the conductive material sheet may comprise at least one_{of copper, aluminum, silver, gold, a noble metal, and a platinum group metal, such as at least} one of ruthenium, rhodium, palladium, osmium, iridium, and platinum._{In some illustrative examples herein, the routing pattern may be formed of the patterned} conductive material sheet, such as a copper sheet, wherein the patterned conductive material_{sheet may be plated with at least one of gold, silver, and platinum group metal(s).In some illustrative examples herein, the electrodes may be arranged on the substrate or} integrated into the substrate having at least one electrode surface exposed with respect to the_{substrate, thereby acting as at least one exposed electrode surface. The exposed electrode} surface may be configured for contacting an analyte. For example, the at least one exposed_{electrode surface may be covered by a membrane. This membrane may be configured for} diffusion of an analyte to be detected by the electrode through the membrane, such as at least_{one of glucose, lactate, Ketone, and creatinine. Accordingly, the membrane may filter the} analyte and only allow certain components of the analyte to contact the electrode(s). Alternatively, the substrate may further comprises a microfluidic system at least partially in fluid communication with the routing pattern, wherein the microfluidic system comprises at least one microchannel formed in or on the carrier. For example, the microfluidic system may comprise the microchannel(s) for implementing tiny channels, reservoirs, valves, and sensors with the_{function of controlling fluids in confined spaces on the carrier when employing the flexible} circuit structure in fluid detection applications. Thus, a microfluidic technology may be implemented in or on the carrier. As indicated above and in some illustrative embodiments of the first aspect, the flexible circuit_{structure may further comprise a light emitting diode (LED) component arranged on the first} surface, the LED component connected to two or more of the connection terminals by conductive tracks routed on the first surface between the LED component and the two or more connection terminals. The two connection terminals in contact with the LED component are not interconnected such that an open circuit is provided with respect to the LED component and the conductive tracks routed between the LED component and the two connection terminals. Accordingly, the LED component may provide a signal once a contacting of the connection terminals by power source for operating the flexible circuit structure during normal operation, the signal showing that the flexible circuit structure is under operation or in use. Optionally, the flexible circuit element may have a timer element electrically coupled to the connection terminals either coupled between the conductive tracks routed between the LED component and at least one of the two connection terminals or coupled between the power source and the connection terminals when coupling the flexible circuit structure with the power source for operation of the flexible circuit structure so as to indicate operation of the flexible circuit structure for a given time interval defined by the timer element switching from an initial nonconductive state into a conductive state after elapsed time is equal to or greater the given time interval. Accordingly, the flexible circuit structure may be equipped with a timing function for one-time use only or for multiple use for the given time interval. Additionally, or alternatively, the LED component may be a single LED element or the LED component may comprise two or more LED elements, such as, without limitation, three LED elements of colors red, blue, and green (or other LED elements emitting peaks at different wavelengths), or at least four LED elements, e.g., four LED elements of colors red, blue, green, and white (or other LED elements emitting peaks at different wavelengths). Accordingly, the LED component may provide signals with varying colors for indicating different states of operation and/or functions. In some illustrative examples herein, the LED component may be arranged adjacent the_{connection terminals in the first surface. For example, the conductive tracks routed to the LED} component may be smaller than a largest length of conductive track routings connecting the connection terminals with the one or more electrodes. In this way, the LED component may be located closer to the connection terminals than an electrode which is located farthest away from the connection terminals. In some illustrative examples herein, the carrier may have a through-hole extending through the carrier along a thickness of the carrier and the LED component may be arranged in alignment with the through-hole such that the LED component may, during operation, emit light through the through-hole towards the second surface of the carrier. For example, in case of the LED component having at least two LED elements, one LED element (or a first subset of plural LED elements) may be arranged and configured to emit radiation away from the carrier without passing through the through-hole, while one other LED element (or a second subset of plural LED elements) may be arranged and configured for emitting light through the through- hole. Accordingly, the LED component may have a dual function, one function of signaling and another function of providing light therapy through the carrier via the through-hole. For example, light treatment may involve radiation with infrared and/or ultra-violet light and/or light of a one or more certain colors in the visible light range, while the LED component substantially emits light at least on the visible light range with respect to the signaling function. However, light emitted outside the visible range may be employed in combination with an appropriate detector in case of a signaling function, as well. In some illustrative examples herein, LED component may be arranged on a carrier portion connected to a remaining carrier body having the connection terminals arranged thereon, by means of a carrier strip portion representing a strip shaped carrier material portion integrally formed and extending, preferably linearly, between the carrier portion and the remaining carrier body, the carrier strip portion having a width dimension smaller than a width dimension of the carrier portion, the width dimension being orthogonal to a length dimension along which conductive tracks routed between the LED component and the connection terminals substantially extend on the carrier strip portion. Accordingly, the carrier strip portion allows twisting of the carrier at the carrier strip portion such that the carrier portion and the remaining carrier portion may be arranged in different orientations with respect to each other, e.g., at least a surface portion of the carrier body being flipped such an orientation of a surface normal vector of the second surface of the carrier body has the same orientation as a surface normal vector of the first surface of the carrier portion. In some other illustrative embodiments of the first aspect, the flexible insulating material may_{comprise at least one of polyetherimide (PEI), polyethylene terephthalate (PET), polyethylenenaphthalate (PEN), polyimide (PI), a glass-epoxy composite, and a cellulose material.} Accordingly, the carrier may be provided in a very compatible manner with respect to a vast variety of applications without being bound by PCB materials. For example, the carrier may be_{formed of a substrate material portion representing a flexible substrate comprised of flexible} materials such as polymeric materials including but not limited to, polyethylene terephthalate film (PET), polyethylene naphthalate (PEN), polyimide foil (PI), polypropylene, polyethylene, polystyrene, polycarbonate, polyether ether ketone (PEEK), or any of a variety of polymer films_{or combinations thereof. However, this does not impose any limitation and, in an alternativeexample, the carrier may include one or more portions that are rigid and comprise one or more} of glass, wood, metal, PVC, silicon, epoxy resin, polycarbonate, or any of a variety of rigid_{materials or combinations thereof. In yet another example, the carrier may include a} combination of one or more flexible materials described herein and one or more rigid materials described herein. In some other illustrative embodiments of the first aspect, the flexible circuit structure may further comprise an adhesive layer formed on one surface of the carrier. In some special illustrative but non-limiting examples herein, the conductive tracks may be formed only on the first surface of the carrier and the adhesive layer may be at least partially formed on the second surface. Alternatively, (some of) the conductive tracks may be formed on the first surface (and optionally also some of the conductive tracks may be formed on the second surface) of the carrier and the adhesive layer may be partially formed on the first surface in surface regions of the first surface which are free of conductive tracks and connection terminals, e.g., adjacent to at least one electrode of the one or more electrodes. Accordingly, the flexible structure may be employed in applications involving an adhesive wearable arrangement, e.g., an adhesive bandage._{In some special illustrative examples herein, the conductive tracks may comprise a conductivematerial such as a metal material or a material containing metallic particles such as, forexample, but not limited to, silver, platinum, palladium, copper, nickel, gold, or aluminum or} carbon or conductive polymer, or some combination thereof. In some aspects, the conductive_{tracks (not illustrated) may include metallic particles and one or more chemical additives (e.g.,solvents, binders, and the like) that improve one or more features of the conductive traces} (e.g., flexibility stretchability, solderability, or the like). The conductive metals or composites_{may be formed as flakes, fine particulates, or nano-particulates, or combinations thereof on at} least one of the first surface and the second surface. In some special illustrative but non-limiting example herein, the flexible circuit structure may further comprise an adhesive layer formed on the second surface of the carrier, wherein at least one electrode of the one or more electrodes is arranged on the second surface, preferably in a surface region of the second surface free of any adhesive material or layer. The at least one electrode on the second side may be connected to the conductive tracks routed on the first surface by means of vertical interconnections extending between the first and second surfaces in the carrier. In some other illustrative embodiments of the first aspect, the conductive tracks may be formed of a conductive material comprising at least one of silver, copper, and gold. An according material may be deposited by physical vapor deposition or printing of conductive ink. The conductive tracks may be patterned by lithography and etching techniques or by patterned printing of the conductive ink. Accordingly, the flexible circuit structure may be provided in a cost-efficient manner and with a high degree of reproducibility. In some other illustrative embodiments of the first aspect, the carrier may be arranged on a base material comprising at least one of silicone, acrylate, hydrocolloid, synthetic based_{rubber, and medical tape so as to provide a wearable arrangement, such as a bandage,} preferably a gauze bandage, such as an adhesive bandage or an elastic bandage. Accordingly, a wearable arrangement may be easily provided. In some illustrative example_{herein, a smart bandage may be provided, the smart bandage optionally comprising a wirelesscircuitry that uses one or more sensors, e.g., impedance and/or temperature sensors,configured to monitor the progression of wound healing. If the wound is less healed or aninfection is detected, the sensors (provided by one or more of the electrodes of the flexible} circuitry structure of the smart bandage, the one or more electrodes being configured as one or more of dedicated sensors by the electrodes being electrically coupled to a dedicated sensor controller configured to control the electrode, process signals of the electrode, and optionally log processed signals and/or transmit signals or processed signals to a supervising control_{unit, either remote or integrated into the smart bandage) may be further configured to inform amodule, e.g., a module comprising a central processing unit (CPU), to apply more electricalstimulation across the wound bed to accelerate tissue closure and reduce infection by means} of one or more stimulation electrodes arranged on the carrier of the smart bandage. Alternatively, one or more electrodes may be provided, the one or more signals configured to detect measuring signals, and a releasable module comprising at least one CPU configured to communicate with one or more electrodes and process one or more signals issued by the one or more electrodes to obtain sensor signals. Additionally, the smart bandage may be configured (either directly by a wireless communication circuitry integrated into the smart bandage or indirectly via an wireless communication circuitry provided by an appropriate_{module releasably connected with the smart bandage) to track sensor data in real time on a} smart phone. In accordance with some illustrative embodiments herein, the flexible circuit structure may be_{configured for use in a smart wearing arrangement, e.g., a smart bandage, for monitoring andtreating wounds and/or monitoring parameters of a person wearing/using the smart wearing} arrangement, such as temperature and/or blood oxygen level and/or presence of liquid, e.g., sweat. In some illustrative examples herein, the smart wearing arrangement may be a fully- integrated wearable bioelectronic system that wirelessly and continuously monitors_{physiological conditions of a person, e.g., a wound bed, via one or more electrodes of the} smart wearing arrangement, such as a custom-developed multiplexed multimodal_{electrochemical biosensor array in an example of wound monitoring.In some special but non-limiting example, a smart bandage may be provided, the smartbandage further performing non-invasive combination therapy through controlled anti-} inflammatory/antimicrobial treatment and electrical stimulated tissue regeneration. In some more illustrative examples herein, the smart bandage may be a wearable patch that is_{biocompatible, mechanically flexible, stretchable, and may conformally adhere to skin/wound} throughout portions of, or during the entire healing process of a wound. Various embodiments may include a system for real-time metabolic and inflammatory monitoring that may allow for higher accuracy and electrochemical stability of the smart bandage for multiplexed spatial and temporal wound biomarker analysis. The combination of electrically modulated antimicrobial agent delivery and electrical stimulation in the wearable smart bandage may accelerate cutaneous chronic wound healing, as well as, overall wound healing in patients. In some specific but non-limiting examples herein, the smart bandage may comprise the carrier_{implemented as a wearable, flexible multilayer substrate with multiplexed sensorsimplemented via multiplexed electrodes disposed thereon that may monitor the physiological} microenvironment of a wound and identify characteristics of the wound. The characteristics of the wound may be monitored via biosensors configured to detect metabolites, amino acids,_{bacteria, vitamins, minerals, hormones, antibodies, pH, UA level, ammonia level, lactate level,} CRP level, glucose level, and other biomarkers. The smart bandage may include an antimicrobial reservoir or hydrogel within the flexible multi-substrate layer. The antimicrobial reservoir or hydrogel may be connected to an outlet, also disposed on the smart bandage, and adjacent to the skin of a patient so that antimicrobial agents and drugs may be released from the antimicrobial reservoir or hydrogel and dispensed from the outlet onto a patient’s skin or into a patient’s wound. In some illustrative examples of a smart wearing arrangement for electrical stimulation, the smart wearing arrangement comprises a flexible circuit structure of the first aspect having one or more electrodes configured as electrostimulation electrode(s), the smart wearing arrangement further comprising an electrical stimulation module releasably connected with the_{carrier of the flexible circuit structure such that the electrostimulation electrode(s) may provideelectrical stimulation to a person. For example, the person may be patient in which case thesmart wearing arrangement may be a smart bandage used to assist with wound healing and} tissue regeneration. In other examples, the person may be a person desiring to strengthen and_{tone muscles by electrical stimulation. In the specific examples herein, the electrical stimulationmodule may comprise a control submodule configured to control the supply of power to the} electrostimulation electrode(s). Additionally, the electrical stimulation module may further comprise another control submodule configured to obtain signals from additional sensors_{representative of wound characteristics and may perform a bioanalysis of the wound ortransmit the signals wirelessly to a user, which may occur discretely or continuously. Thecontrol module may also receive signals for wound treatment from a user or autonomously and} dynamically administer wound treatment based on programmed threshold parameters for_{particular treatments in reference to certain wound characteristics. Herein, the smart bandagemay further include a wireless communication module that may connect the smart bandage} device to another wireless device, such as a mobile phone, computer, tablet, or medical_{station. The control module on the smart bandage may include a non-transitory computer} readable storage medium that includes instructions to receive and process signals from the sensors representative of wound characteristics, transmit the received signals via the wireless communication module to another wireless device, receive signals from a wireless device, transmit signals to the antimicrobial reservoir/hydrogel/outlet and electrical stimulation module, and in some embodiments, autonomously process sensor signals to determine whether they_{exceed threshold values and autonomously initiate treatment. Advantageously, such smart} wearing arrangements may implement wearable sensors integrated with telemedicine allowing_{to support safe and efficient monitoring of individual health, which would allow for timely} intervention for infection and treatment of wounds and other medical conditions._{In some other illustrative embodiments of the first aspect, the conductive tracks may comprise} at least two conductive tracks electrically coupling at least two of the connection terminals with a sensor element, preferably an oxygen sensor element, the conductive tracks routed between the two terminals and the oxygen sensor element in a curvy routing pattern. The curvy routing pattern may have at least one routing portion of at least partially a wavy or sinusoidal shape. For example, the routed conductive tracks adjacent the oxygen sensor element may be the curvy routing pattern. The curvy routing pattern may be 10% to 50% of the conductive tracks routed between the connection terminals and the oxygen sensor element. The curvy routing pattern may provide an improved flexibility at the oxygen sensor element, allowing the oxygen sensor element arranged at body parts that are subjected to bending motions, such as fingers,_{toes, hands, feet, etc. That is, the conductive tracks may comprise at least two conductive} tracks electrically coupling at least two of the connection terminals with a sensor element, preferably an oxygen sensor element, the conductive tracks routed between the two terminals and the oxygen sensor element in a curvy routing pattern having at least one routing portion of at least partially a wavy or sinusoidal shape. In some of the illustrative embodiments of the first aspect, the LED component and the oxygen_{sensor element may be arranged on the first surface. Accordingly, a correct connection} between a module associated with the operation of the oxygen sensor element and the connection terminals may be ensured by the LED component and/or the LED component may be used for indicating operation of the oxygen sensor element, e.g., by means of a designated colored light or simply by the LED in the on-state, and/or indicating a warning signal in case that measurement signals of the oxygen sensor element exceed predetermined threshold values. In some other illustrative embodiments of the first aspect, the one or more electrodes may comprise at least one stimulation electrode arranged on the carrier in a substantially spiral routing. Accordingly, a stimulation area of sufficient size may be provided. In some illustrative examples herein, the at least one stimulation electrode may be arranged on the second surface, the at least one stimulation electrode being connected to conductive tracks by via connections extending through the carrier between the first and second surfaces. Accordingly, the connection terminals may be easily accessible to contacting with a dedicated module, while the stimulation electrode(s) may be reliably brought into contact with a skin of a user. In some other illustrative embodiments of the first aspect, wherein the flexible circuit structure may further comprise a microheating structure arranged on at least one of the first and second surfaces, wherein the microheating structure is configured to heat the microheating structure to a temperature in a range from about 36°C to about 90°C. Accordingly, heat treatment may be provided in an easy manner. In some illustrative examples herein, the microheating structure may be arranged on the carrier so as to at least partially enclose the at least one stimulation electrode on the carrier. In some special example herein, the microheating structure may be formed by a positive temperature coefficient (PTC) material or carbon-conductive material. Additionally or alternatively, the microheating structure may be arranged in thermal contact with a layer of a material having a relatively high thermal conductivity, more preferably having a thermal conductivity of at least 1_{W/(m K), such as more than 2 W/(m K) or more than 5 W/(m K) or more than 10 W/(m K) ormore than 20 W/(m K) or more than 50 W/(m K). Accordingly, a homogeneous heating may} and/or heat spreading may be achieved. In some other illustrative embodiments of the first aspect, the flexible circuit structure may further comprise at least one pH sensor and/or at least one exudate sensor arranged on carrier. Accordingly, the flexible circuit structure may be applied in a vast range of applications. In some illustrative examples herein, the at least one pH sensor and/or at least one exudate sensor may be arranged with respect to the at least one stimulation electrode such that the at least one pH sensor is arranged within an area covered by at least one stimulation electrode. Additionally or alternatively, the at least one exudate sensor may be arranged on a perimeter around the at least one stimulation electrode. Accordingly, a spatially resolved monitoring of a wound may be achieved. In some other illustrative embodiments of the first aspect, a subset of the conductive tracks are routed on the first surface so as to form at least one antenna loop portion operable in a frequency range starting from about 1 kHz to about 10 GHz. Accordingly, a wireless communication with the flexible circuit structure may be provided. In some other illustrative embodiments of the first aspect, the flexible circuit structure may further comprise an electric module having a microchip, the electric module being releasably coupled to the connection terminals. Accordingly, different functions and operations may be performed on a flexible circuit structure. In some illustrative examples herein, the electric module may further comprise an electric power supply for powering the flexible circuit structure, the flexible circuit structure being configured as an active circuit structure. Accordingly, the flexible circuit structure may be autonomously powered. In some illustrative examples herein, the flexible circuit structure may be configured as a passive circuit structure. Accordingly, the flexible circuit structure may be energy efficient and be operated on demand by remote control and/or allow remote monitoring. In some other illustrative embodiments of the first aspect, the flexible circuit structure may further comprise a fluid collector system formed on the carrier, such as on the second surface. For example, the fluid collector system may comprise at least one microchannel formed in the second surface. The at least one microchannel may be provided in a semicircular or circular or elliptical or spiral or sigma-shaped pattern. At least one of the conductive tracks may be formed so as to at least partially extend within the at least one microchannel. In some illustrative examples herein, the fluid collector system may be coupled with a pH sensor and/or a sweat sensor and/or an Na+ sensor. For example, such flexible circuit structures configured or provided for implementing flexible wearable sweat sensors allow continuous, real-time, noninvasive detection of sweat analytes, may provide insight into human_{physiology at the molecular level, and may have received significant attention for their} promising applications in personalized health monitoring. Herein, electrochemical sensors may_{be an advantageous choice for wearable sweat sensors due to their high performance, low} cost, miniaturization, and wide applicability. For example, such a flexible circuit structure may_{implement a wearable sweat sensor which may monitor both the sweat rate and sweat} electrolyte concentration. An according sensor device may be an effective tool for determining_{appropriate rehydration, for example, by monitoring both the local sweat rate and sweat} electrolyte concentration continuously._{In the illustrative examples herein, the flexible circuit structure comprises the carrier having a} short microfluidic pathway implemented by the one or more microchannels configured for_{guiding sweat appearing on skin of a user to a small space in the surface of the carrier,preferably at an end of (each of) the microchannel(s) to form a quantifiable droplet. The sweatrate may be assessed from the time for the droplet to appear and droplet volume, optionally, afurther integrated electric sensor may be configured for detecting sodium chloride} concentration in each sweat droplet. In some other illustrative embodiments of the first aspect, the carrier may have a cutting pattern provided on the first surface. The cutting pattern may define at least one line not extending across the conductive tracks, the cutting pattern being configured such that, upon cutting the carrier along the at least one line, two carrier material portions separated by the at least one line are displaceable with respect to each other. Accordingly, the carrier may be initially provided in a compact shape, while the cutting pattern allows to expand the flexible circuit structure for adjusting the size of the flexible circuit pattern to various sized of users. In some other illustrative embodiments of the first aspect, the connection terminals may be arranged at a geometric center of the first surface. Additionally, or alternatively, the connection terminals may be arranged in a pattern with one or more substantially parallel lines of terminals. Accordingly, a compact design of the carrier may be provided._{In a second aspect of the disclosure, a method of fabricating a flexible circuit structure isprovided. In the illustrative embodiments herein, the method comprises providing a carrier of} a flexible insulating material, preferably a carrier strip, forming conductive tracks and one or more electrodes on at least one of a first surface of the carrier and a second surface of the carrier opposite the first surface, and forming connection terminals on the first surface and electrically coupling to the one or more electrodes via at least some of the conductive tracks. In some examples of the second aspect, the flexible circuit structure, such as the flexible circuit structure of the first aspect, may be integrated into bandage, such as a patch. In some illustrative embodiments of the second aspect, the method may further comprise_{providing a pattern of cutting lines, wherein cutting lines of the pattern of cutting lines partiallyextending between some of the conductive tracks. In some illustrative examples herein, the} method may further comprise cutting the pattern of cutting lines. Furthermore, the method may in some more advantageous examples herein, the method may further comprise separating_{the flexible substrate structure along the pattern of cutting lines such that portions of the carrierseparated by cutting lines are spaced apart with a carrier-free portion extending there between.} In some illustrative embodiments of the second aspect, the flexible substrate of the first aspect is formed. In some illustrative embodiments of the first and second aspect described above, a flexible circuit structure comprising conductive tracks may be provided, the conductive tracks formed_{by intricate patterns of the conductive tracks on a carrier. For example, conductive tracks may} be selectively printed or otherwise deposited to form circuit tracks by any of a variety of printing or additive deposition methodologies, including, for example, any form of gravure, flatbed screen, flexography, lithography, screen, rotary screen, digital printing, inkjet printing, aerosol_{jet printing, 3-D printing, and like print methods, or combinations thereof. In some examples,the conductive material used for forming conductive tracks may be in the form of a printableconductive ink, toner, or other coating. The electronic inks may include non-conductive} particles or particulates that are included to mechanically pierce or penetrate a native oxide formed on a metallic surface and thereby create a low-resistance electrical contact between_{the metallic surface and the electronic ink. In some such examples, the non-conductive} particles may have a surface that includes features useful for piercing the oxidized metallic surface. In other examples, the conductive particles may have a surface that includes features useful for piercing the oxidized metallic surface. In some examples, the ink includes solvents and/or binders to assist with removing or penetrating the native oxide layer to expose a non-_{oxidized aluminum surface. In some special illustrative but non-limiting example, silver ink maybe thermally cured, such that electrical testing after completion of the cure process provides a} mechanically and low electrical resistance between the silver ink and metallic surface. In some_{other special illustrative but non-limiting example, a fabrication process may be provided, thefabrication process including printing silver ink directly onto an oxidized metallic surface to form} a mechanically strong and electrically low-resistance interconnect to form an electrical circuit._{In a third aspect, a bandage, for example a patch, is provided, the bandage comprising a} flexible circuit structure according to the first aspect. Alternatively, a transducer for a biosensor may be provided, the transducer comprising the flexible circuit structure of the first aspect. Although various illustrative embodiments are described above with respect to the first to third aspects, this does not impose any limitation and one or more illustrative embodiments of one of the first to third aspects may be combined with or implemented in at least one other of the first to third aspects. Other features and aspects of the disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features in accordance with various embodiments. The summary is not intended to limit the scope of the invention, which is defined solely by the claims attached hereto. Brief Description of the Drawings Various illustrative embodiments and other advantages of the various aspects of the present_{disclosure will become apparent from the detailed description of the accompanying Figures as} presented below._{Figure 1 shows a schematic top view of a flexible antenna structure in accordance with some} illustrative embodiments of the present disclosure._{Figure 1a schematically shows a cross-sectional view along line 1a-1a in Figure 1.Figure 2 shows a schematic top view of a flexible antenna structure in accordance with some} other illustrative embodiments of the present disclosure._{Figure 3 schematically shows a smart wearing arrangement based on the flexible antenna} structure shown in Figure 2. Figure 4 schematically shows a cross-sectional view of an oxygen sensor of the smart wearing arrangement of Figure 3._{Figures 5a and 5b schematically show in a bottom view and a top view a flexible antenna} structure in accordance with some other illustrative embodiments of the present disclosure._{Figure 6 shows a schematic top view of a flexible antenna structure in accordance with some} other illustrative embodiments of the present disclosure._{Figure 6a schematically shows a cross-sectional view along line 6a-6a in Figure 6.Figure 6b schematically shows a cross-sectional view along line 6b-6b in Figure 6.Figure 7 shows a schematic top view of a flexible antenna structure in accordance with some} other illustrative embodiments of the present disclosure._{Figure 8 shows a schematic top view of a flexible antenna structure in accordance with some} other illustrative embodiments of the present disclosure._{Figures 9a and 9b schematically show in a bottom view and a top view a smart wearing} arrangement in accordance with some illustrative embodiments of the present disclosure._{Figure 10 shows a schematic top view of an enlarged portion of a flexible antenna structure in} accordance with some illustrative embodiments of the smart wearing arrangement of Figure 9b._{Figure 11 shows a schematic sectional view of a flexible antenna structure in accordance with} some other illustrative embodiments of the present disclosure. Figure 12 schematically shows steps in an exemplary process according to some illustrative embodiments of the present disclosure._{Figure 13 schematically shows additional process steps in accordance with some illustrative} embodiments of the present disclosure_{The Figures accompanying the present disclosure are only provided for schematically showingsome concepts and aspects of the present disclosure without showing all possible details of} certain embodiments and without necessarily being actually to scale. Detailed Description of Preferred Embodiments_{The illustrative embodiments described below relate to a flexible circuit structure and a smart} wearing arrangement in various aspects of the present disclosure. Although embodiments_{below are described with respect to a smart bandage with a flexible circuit structure as an} illustrative embodiment of a smart wearing arrangement, this does not impose any limitation and another type of smart wearing arrangement may be considered in a different field of application instead. In medical applications, smart wearing arrangement may be employed as smart bandages_{used in chronic wound healing, for example. Generally, chronic wound healing may be} understood as a complex biological process including four integrated and overlapping phases: hemostasis, inflammation, proliferation, and remodeling. At each stage of the healing process, the chemical composition of the wound exudate may change, this may indicate the stage of healing and even the presence of infection. For example, increased temperature may be associated with bacterial infection; acidity (pH) may indicate a healing state with balanced protease activities and effective ECM remodeling; elevated uric acid (UA) may indicate wound severity with excessive reactive oxygen and inflammation; lactate and ammonium may be biomarkers for soft-tissue infection diagnosis in diabetic foot ulcers; and wound exudate glucose may have a correlation with blood glucose and bacterial activities, which may provide therapeutic guidance for clinical diabetic wound treatment. As such, a better understanding of the wound characteristics or environment through in situ biomarker analysis, via for example, a smart bandage, could reduce hospitalization time, prevent amputation, aid in therapeutic studies, and improve other personalized treatments._{Further, increases in temperature over time may be linked to inflammation. Elevated levels ofUA after infection may be due to upregulation of xanthine oxidase, a component of the innateimmune system responding to inflammatory cytokines in chronic ulcers, which may play a role} in the purine metabolism to produce UA. For example, pH, lactate, and ammonium may all be acidity related and their elevation during bacterial infection may be monitored. Additionally, glucose levels in infected wound fluid may have a greater than approximately 35% decrease after infection, due to the increased glucose consumption of bacteria activities. The smart bandage may monitor decreases in temperature, pH, lactate, UA, and ammonium in relation_{to levels during infection and increases in glucose level, to indicate that treatment has improved} the state of the infection in the wound. These levels may also be monitored to determine whether digestion has occurred in diabetic patients, or whether digestion is not occurring properly, as biomarkers may also change during the course of digestion. Advances in digital health and flexible electronics have transformed conventional medicine practices into remote at-home healthcare (i.e., telemedicine). Wearable biosensors, for example a smart bandage, may allow for real-time and/or continuous monitoring of physical vital signs and physiological biomarkers in various biofluids such as sweat, saliva, and interstitial fluids, among others. Generally, wound dressings provide a moist wound environment, offer protection from secondary infections, remove wound exudate, and promote regeneration. However, chronic wounds require greater flexibility, breathability, and biocompatibility of the dressing to protect the wound bed from bacterial infiltrations and infection, and to modulate wound exudate levels. Further, chronic wounds may provide a more_{complex wound exudate matrix that may affect biosensor performance. As such, personalized} chronic wound therapy may require close monitoring of crucial wound healing biomarkers in_{the wound exudate, beyond what may be discretely monitored at individual in patient visits.} To address these challenges, a fully -integrated wireless wearable bioelectronic system that more effectively monitors the physiological conditions of the wound bed via multiplexed and multimodal wound biomarker analysis, and performs combination therapy through on-demand electro-responsive controlled drug or antimicrobial agent delivery for anti-inflammatory antimicrobial treatment and exogenous electrical stimulation for tissue regeneration was developed as a smart bandage. The smart bandage may be a wearable patch that is_{mechanically flexible, stretchable, and may conformally adhere to the skin/wound throughout} portions of, or the entirety of, the wound healing process. The smart bandage may improve comfort levels when worn by a patient and reduce skin irritation at the location the smart bandage is placed. The smart bandage may include various biosensors that may monitor various wound biomarkers/characteristics including temperature, pH, ammonium, glucose, lactate, UA, and other biomarkers indicative of wound parameters. In various embodiments, the smart bandage may monitor, in real-time or at discrete occasions, the biomarkers or characteristics of the wound through wound exudate. The smart bandage may monitor these biomarkers or characteristics in situ using custom-engineered electrochemical biosensor arrays. The multiplexed biomarker/wound characteristic information collected by the smart_{bandage via the biosensors may reveal spatial and temporal changes in the wound} microenvironment as well as inflammatory status of the wound through different stages of healing. In addition to the multiplexed biosensors, the smart bandage may be equipped with an on- demand electro-responsive drug release and antimicrobial agent delivery system, loaded with an antimicrobial and/or anti-inflammatory peptide. The delivery system may release the drugs or antimicrobial agents under an applied positive voltage, such that when a positive voltage is applied, the electroactive hydrogels may release the dual-function peptide, or other drug, which_{may increase elimination of bacteria (or other pathogens) and modulate inflammatoryresponses in the wound bed during various stages of healing. In various embodiments, the on-} demand delivery system may be modified with different electroactive hydrogels to deliver other drugs (including positively and negatively charged drugs and biomolecules, e.g., proteins, peptides, and growth factors). Similarly, the integration of an electrical stimulation therapeutic module may facility cell motility and proliferation, and ECM deposition and remodeling in the process of wound regeneration resulting in increased cutaneous wound healing. In general, the combination of electrically modulated antimicrobial agent delivery and electrical_{stimulation on the smart bandage may accelerate chronic wound recovery and/or closure such} that one or more of the embodiments described below may address at least one of these aspects. With regard to Figure 1, a flexible circuit structure 1 in accordance with some illustrative embodiments of the present disclosure is illustrated. The flexible circuit structure 1 comprises a carrier 2 of a flexible insulating material, conductive tracks 4 and electrodes 6 formed on a first surface of the carrier 2, and connection terminals 5 formed on the first surface of the carrier 2, the connection terminal electrically coupling to the electrodes 6 via the conductive tracks 4. The carrier 2 may be provided in the form of a carrier strip, that is, substantially of a strip shape, the strip shape indicating a shape having a length and a width dimension as two orthogonal dimensions, a length dimension (or simply “length) equal to or greater than a width dimension (or simply “width”) such that length ≥ width, possibly with one or more rounded corners and/or curved lines or edges. In some special but non-limiting examples herein, a maximum width of the carrier 2 may be smaller than a maximum or minimum length of the carrier 2. The conductive tracks 4 comprise a plurality of conductive track lines 4a, 4b, and 4c, thereby the conductive tracks 4 representing a plurality of conductive tracks lines. Each of the conductive track lines 4a to 4c may extend between respective ones of the connection terminals 5 and electrodes 6. For example, the conductive track lines 4a may extend between respective terminals of the connections terminals 5 and electrodes 6a and 6b of the electrodes 6, while conductive track lines 4b may extend between respective ones of the connection terminals 5 and electrodes 6c and 6d. For example, an illustrative connection terminal 5a may be electrically coupled with the electrode 6d via conductive track lines 4b extending there between. With ongoing reference to Figure 1, the flexible circuit structure 1 may further comprise an LED component 8 arranged on the first surface of the carrier 2. The LED component 8 may be connected to 2 of the connection terminals 5 by conductive track lines 4c routed on the first surface between the LED component 8 and the two connection terminals of the connection terminals 5. In some illustrative embodiments of the flexible circuit structure 1, the LED component 8 may be a single LED element or the LED component 8 may comprise two or more LED elements such as, without limitation, three LED elements of colors red, blue, and green (or other LED elements emitting peaks at different wavelengths), or at least four LED elements such as four LED elements of colors red, blue, green, and white (or other LED elements emitting peaks at different wavelengths). However, this is only illustrative and the person skilled in the art will appreciate that any desired number of LED elements, such as two LED elements or five LED elements or more LED elements may be included into the LED component 8. The LED component 8 may be connected to an appropriate number of connection terminals of the connection terminals 5, depending on the number of LED elements included into the LED component 8. For example, a number of “n” LED elements (n being a natural number, i.e., n ≥ 1) included into the LED component 8 may be coupled with (n+1) connection terminals of the connection terminals 5 by means of a respective number of conductive track lines 4b. In this case, each of the individual LED elements of the LED component 8 may be individually controlled when controlling the intensity of light emitted by the individual LED elements_{included into the LED component 8 and it is possible to emit light with different colors by the} LED component 8, even allowing signals of changing color continuously or intermittently emitted by the LED component 8 during its operation. In case that light of single color is to be emitted by the LED component 8 having a plurality of LED elements, it may be sufficient that only two conductive track lines 4b connecting the LED component 8 with two connection terminals of the connection terminals 8 may be sufficient. In some illustrative embodiments of the flexible circuit structure 1 shown in Figure 1, the component 8 may be arranged adjacent to connection terminals 5 in the first surface of the carrier 2, the conductive track lines 4b being routed to the LED component possibly being smaller than a largest length of conductive track routings connecting the connection terminals with the electrode 6a or 6d. Still referring to Figure 1, the LED component 8 may be arranged on a carrier portion connected_{to a remaining carrier body of the carrier 2 having the connection terminals 5 arranged thereon} by means of a carrier strip portion representing a strip shaped carrier material portion integrally formed and extending between the carrier portion and the remaining carrier body of the carrier_{2. For example, the carrier strip portion as shown in Figure 1 may linearly extend between the} carrier portion on which the LED component 8 is arranged and the remaining carrier body on which the connection terminals 5 are arranged. The carrier portion on which the LED component 8 is formed, may be in accordance with some illustrative but non-limiting examples of a circular or elliptical shape or may be of a polygonal shape. With ongoing reference to Figure 1, the electrode 6a to 6d may be arranged on the remaining carrier body or connected to the remaining carrier body by an integrally formed and possibly_{linearly extending strip shaped carrier material portion similar to the LED component 8.} In some illustrative but non-limiting examples herein, one or more electrodes, e.g., the electrodes 6a and 6b, may possibly be configured as electrodes intended for direct contact with a skin of a user, therefore possibly being coupled with the remaining carrier body of the carrier 2 via strip shaped carrier material portions having a width smaller than a width of the electrodes 6a and 6d, thereby allowing a twisting of the electrodes 6a and 6d. For example, the carrier portions of the carrier 2 supporting the electrodes 6a and 6d may be twisted, for example, the electrode 6a and 6d may be flapped over so as to face towards the skin of the user during operation of the flexible circuit structure 1, i.e., arrangement of the flexible circuit structure on a user during operation when employed in a smart wearing arrangement, for example. Accordingly, an easy fabrication of the flexible circuit structure 1 becomes possible to the extent that any of conductive tracks 4, electrodes 6, connection terminals 5, and LED component 8 may be formed on the same main surface of the carrier 2. However, this does not impose any limitation on the present disclosure and at least one of the electrodes 6a to 6d may be arranged on an opposite main surface of the carrier 2 (i.e., a main surface opposite to the main surface illustrate in the top view of Figure 1) by further providing a vertical interconnection (not illustrated) extending in the carrier 2 between the two opposite main surfaces of the carrier 2. Referring to Figure 1a, a cross sectional view of the carrier 2 at the line 1a-1a is schematically illustrated, the conductive track lines for c being arranged on the carrier 2, the LED component 8 being arranged on the conductive track lines 4c and in electrical contact therewith. The LED component 8 may be in alignment with a masking pattern 9 provided on the carrier 2 overlying the conductive track lines 4c, leaving a portion of the conductive track lines 4c exposed for locating the LED component 8 at a respective position on the carrier 2. As illustrated in Figure 1a, the carrier 2 may have a through-hole formed therein, the through hall completely extending through the carrier 2 along its thickness direction (i.e., orthogonal to a main surface of the carrier 2) for exposing the LED component 8 towards the opposite main surface of the carrier 2, thereby allowing the LED component emitting light towards two opposite directions away from the carrier 2. Accordingly, the LED component 8 possibly having a plurality of LED elements, may have one or more LED elements used for signaling by emitting light away from the LED component 8 along a vertical upwards oriented direction in the illustration of Figure 1a, possibly further including at least one other LED element configured for emitting light, e.g., in the infrared or ultraviolet spectrum for applying light treatment by emitting light through the through-hole in the carrier 2 alone a vertically downward oriented direction in the illustration of Figure 1a. However, this does not impose any limitations on the present disclosure and the person skilled in the art is aware of other alternatives as described with respect to the first aspect in the preceding description. Although Figure 1a explicitly shows a through-hole extending completely through the carrier 2 in alignment with an arrangement of conductive track lines 4c routed below the LED component 8, this does not impose any limitation and the carrier 2 may not have any through-hole formed therein, i.e., the material of the carrier 2 may be continuous below the LED component 8. With respect to the electrodes 6a to 6d, these electrodes may implement an electrical stimulation function or may be configured as electrodes having a sensor function when connected to an appropriate sensor device. With respect to Figure 1, the connection terminals 5 may be implemented as connector recesses or holes provided in the carrier 2 which may be configured for mating with connector pins (not illustrated) of an electric and/or electronic device such as an electronic module or electric power source combined with or separate to the electronic module. Herein, the conductive track lines 4c represent an open circuitry which is closed when contacting the connection terminals with appropriate contacts (not illustrated) of an electric and/or electronic device (e.g., module) (not illustrated), to be brought into contact with the connection terminals 5. Accordingly, upon closing an electric circuit provided by the conductive track lines 4c and_{its connected connection terminals of the connection terminals 5, the LED component 8 may} be powered with electrical power, thereby indicating a correct connection of the flexible circuit structure with the electric and/or electronic device to be connected with the flexible circuit structure 1. Additionally, the LED component 8 may be electrically coupled with an appropriate controller (not illustrated) of the electric and/or electronic device to be coupled with the flexible circuit structure 1 such that signaling and/or treatment functions may be provided by the LED component 1 as described with respect to the first aspect in the description above. The carrier 2 may be made of a flexible insulating material as described above with respect to the first aspect. The conductive track lines may be formed in accordance with the disclosure as presented above with respect to the first and second aspects of the disclosure. Referring to Figure 2, a top view of a flexible circuit structure in accordance with some illustrative embodiments of the present disclosure is schematically shown. The top view in Figure 2 shows the flexible circuit structure 10 comprising a carrier 10a of flexible insulating_{material, conductive tracks are formed on one surface of the carrier 10a, connection terminals} 15 representing a plurality of connection terminals with one illustrative connection terminal 15a, and a landing area 11 of the carrier and a configured to receive an electric and/or electronic device (not illustrated) to be electrically coupled with the flexible circuit structure via the connection terminals 15. The landing area 11 may be provided with attachment means_{configured for releasably accommodating the electric and/or electronic device (not illustrated)} when connecting the electric and/or electronic device (not illustrated) via the landing area 11 to the flexible circuit structure 10. However, this does not impose any limitations on the present disclosure and the landing area 11 together with the connection terminals 15 may be implemented for a one-time and permanent attachment of the electric and/or electronic device (not illustrated) on the carrier 10a. In some illustrative examples, the landing area 11 may be equipped with a mechanical coupling structure (not illustrated) for permanently or releasably coupling the electric and/or electronic device (not illustrated) with the flexible circuit structure 10 via the landing area 11. For example, at least one of clamps, hooks, noses etc. may be provided as mechanical coupling structure(s) (not illustrated) on the carrier 10a. With ongoing reference to Figure 2, the carrier 10a may have at least one cutting line CT formed therein along which the carrier 10a may be cut for expanding the shape of the flexible_{circuit structure 10 for cutting the carrier 10a along the cutting line CT. In some special} illustrative but non-limiting examples herein, the cutting line CT may be implemented via a recessing provided in the surface of the carrier 10a. For example, the cutting line CT may extend completely around the flexible circuit structure, i.e., the CT may completely surround the conductive tracks 14, the connection terminals 15, and the lines 18. In some illustrative but non-limiting examples herein, the cutting line CT may have a shape defining the landing area 11 at the connection terminals 15. As shown in Figure 2, the carrier 10a provided at the stage shown in Figure 2, that is before a cutting process is applied for cutting along the cutting line CT, may be a sheet of carrier material according to the carrier 10a shown in Figure 2. The sheet of carrier material shown in Figure 2 may have a test circuitry formed thereon, such as test lines extending along edges at opposite ends shown in Figure 2. The test lines may be routed to a test connection terminal indicated by a partial circular or elliptical portions at the right lower end of the shape surrounded by the cutting line CT. When cutting the cutting line CT, the test lines will be disrupted and a connection between the conductive tracks 14 and the test circuitry is disconnected. Accordingly, in the stage illustrated in Figure 2, a testing of the flexible circuit structure 10 may be performed in the absence of a module connected to the connection terminals 15 in the landing area 11. Additionally, an optional LED component formed vertically above the connection terminals in Figure 2, may be connected to the connection terminals 15 in accordance with the embodiments described in the context of Figures 1 and 1a with respect to the LED component 8 above. Optional test lines may be provided for allowing a testing of the LED component at the stage shown in Figure 2 in the absence of a module connected to the connection terminals 15. The conductive tracks 14 comprise conductive track lines 18 formed of at least two conductive tracks electrically coupling at least two of the connection terminal 15 with a sensor element 18a, e.g., an oxygen sensor element, the conductive tracks being routed between the at least two terminals of the connection terminals 15 and the sensor element 18a in a curvy routing pattern 18b. The curvy routing pattern 18b may have at least one routing portion of at least partially a wavy or sinusoidal shape, e.g., a bent or deformed sinusoidal shape as shown in Figure 2. However, this does not impose any limitation on the present disclosure and the skilled person will appreciate that any curved routing implementing at least a rounded portion of routed_{track line may be formed adjacent to the sensor element 18a. For example, the curvy routing} pattern 18b may be partially encircled by cutting lines CT such that the curvy routing pattern 18b may be partially cut out from the carrier 10a when cutting along the cutting line CT. After cutting, the curvy routing pattern 18b may be folded away from the remaining carrier 10a. The conductive tracks comprise at least two conductive tracks electrically coupling at least two of the connection terminals with a sensor element, preferably an oxygen sensor element, the conductive tracks routed between the two terminals and the oxygen sensor element in the_{curvy routing pattern 18b having at least one routing portion of at least partially a wavy or} sinusoidal shape. In accordance with some illustrative examples, additional cutting lines may be present, e.g., a cutting line extending between wavy routed lines in the curvy routing pattern 18b such that portions of the curvy routing pattern 18b may be separated by at least one cutting line_{extending there between. Accordingly, the curvy routing pattern 18b may be extendable after} cutting one or more additional cutting lines there between._{Referring to Figure 3, a schematic view of a smart wearing arrangement 10’ comprising the} flexible circuit structure 10 of Figure 2 is shown during operation. The smart wearing arrangement 10’ comprises the flexible circuit structure 10 which is electrically coupled with a module 11’. The module 11’ comprises electric circuitry for driving the sensor element 18a of the flexible circuit structure 10 e.g., providing electrical signals to the sensor element 18a such that the sensor element 18a may perform its dedicated function as a sensor element. The module 11’ may further comprise an electric power source, e.g., batteries for supplying electrical power to the flexible circuit structure 10. Additionally, or alternatively, the module 11’ may further comprise an antenna structure (not illustrated) for wireless communication with the sensor element 18a on the flexible circuit structure 10 or a processor (not illustrated) of the module 11’ and/or powering the module 11’ and the flexible circuit structure 10 by electromagnetic radiation received by the antenna structure (not illustrated). The module 11’_{may be accommodated on the flexible circuit structure 10 at the landing area 11 and may be} releasably coupled with the connection terminals 15 of the flexible circuit structure 10. The flexible circuit structure 10 may be cut along the cutting lines CT in Figure 2 such that the curvy_{routing pattern in a carrier portion 18’ may be separated from the remaining carrier body of the} carrier 10a such that the curvy routing pattern in the carrier portion 18’ or cut portion supporting the curvy routing pattern may be aligned with a finger F of a hand H of a user, e.g., a patient under examination by the smart wearing arrangement or a user using the smart wearing arrangement 10’. The carrier portion 18’ may further have a “T” shaped end portion 18a’ which may have adhesive or patch like surfaces allowing attachment of the carrier portion 18’ at the finger F such that the sensor element 18a (see Figure 2) is appropriately positioned on the finger F at the fixed spatial location on the finger F. Referring to Figure 4, an implementation of the sensor element as an oxygen sensor element is schematically illustrated, the sensor element 18a in Figure 2 implemented by means of the oxygen sensor element 18a’’ having a light source L1 and L2 together with a light detector LD in electrically coupling with the curvy routing pattern 18 in Figure 2. However, this does not impose any limitation on the present disclosure and the person skilled in the art would appreciate that the sensor element 18a may be implemented as an electrostimulation electrode or any other appropriate sensor element. For example, the light sources L1 and L2 may be configured for emitting light with wavelengths in different wavelength regions detectable by the light detector LD. As shown in the illustration of Figure 4, the oxygen sensor element 18a’’ may be implemented by a carrier portion extending over fingertip and nail of finger F as opposed to the implementation in Figure 2 showing a sensor element leaving fingertip and nail exposed. However, the person skilled in the art will appreciate that different designs of the carrier portion 18’ and end portion 18a’ in Figure 3 or the oxygen sensor element 18a’’ are possible without limiting the smart wearing element 10’ of Figure 2 to 4 to a specific layout and design, for example, by appropriately shaping a form of the cutting line CT in Figure 2. Referring to Figure 5a and Figure 5b, a flexible circuit structure 20 in a top view shown in Figure 5b and a bottom view shown in Figure 5a as schematically shown, the flexible circuit structure 20 having a carrier 20a with two opposing main surfaces 20a1 and 20a2 of the carrier 20a. The surface 20a1 may be a surface of the carrier which faces towards a skin of a user during operation of the flexible circuit structure, while the surface 20a2 may be oriented to face away from the skin of the user during operation of the flexible circuit structure 20. Referring to Figure 5a, electrodes 26, e.g., 26a and 26b are formed at separate positions in the surface 20a1. Each of the electrodes 26a and 26b are electrically coupled by conductive track lines with vertical interconnections 29 extending through the carrier 20a along a thickness along a thickness of the carrier 20a between the surfaces 20a1 and 20a2. Referring to Figure 5b, connection terminals 25 are formed in the surface 20a2, the connection terminals 25 being electrically connected with the vertical interconnections 29 via conductive track lines routed in the surface 20a2. Furthermore, the connection terminals 25 may be electrically connected with an antenna pattern 27a and 27b formed in the surface 20a2 by conductive track lines 24 (the conductive track lines 24 are indicated in Figure 5a by broken lines for illustrating the conductive track lines 24 which may not be visible in the view of Figure 5a depending on a transparent or translucent optical characteristic of the material of the carrier 20a. The antenna pattern 27a and 27b may be formed on positions in the surface 20a2 being aligned with respect to the thickness of the carrier 20a at positions at which the electrodes 26a and 26b are formed in the opposite surface 20a1. The connection terminals 25 may be arranged at a surface center of the carrier 20a such as a center of the surface 20a2. Accordingly, the surface 20a2 may provide an accommodation and landing area for receiving an electric and/or module (not illustrated) to be electrically coupled with the connection terminals 25 of the flexible circuit structure 20. For example, the antenna pattern 27a and 27b_{may be provided as antenna dipole pattern configured for receiving electromagnetic radiation} for wireless communication with the flexible circuit structure 20, i.e., the electric and/or electronic module (not illustrated) to be coupled with the connection terminals 25. Furthermore, the antenna pattern 27a and 27b may be configured for receiving electromagnetic radiation to actively power the flexible circuit structure 20. For example, a track line width of the conductive track lines 24 may be greater than a track line width of track lines connecting the connection terminals 25 with the vertical interconnection 29. For example, the track line width ratio between track lines 24 and track lines connecting connection terminals 25 with the vertical interconnections 29 may be greater than 2 or greater than 5 or greater than 10. Referring to Figure 5a, the electrodes 26a and 26b may be electrodes configured for electric stimulation, thereby the electrodes 26a and 26b being formed in a spiral shape, e.g., a tightly wound spiral shape allowing to increase an area for electric stimulation by each of the electrodes 26a and 26b. The antenna patterns 27a and 27b may implement each an antenna loop portion operable in_{a frequency range starting from 1 kHz to about 10 GHz.Referring to Figure 6, a flexible circuit structure 30 is schematically shown in a top view, the} flexible circuit structure 30 comprising a carrier 30a, conductive tracks 34 and electrodes 36_{formed on at least one surface of the carrier 30a, and connection terminals 35 formed in oneof the surfaces of the carrier 30a. Additionally, an optional LED element 38 corresponding tothe LED component 8 described above with respect to Figures 1 and 1a may be provided.The electrodes 36 may be provided by means of electrodes arranged on opposite ends of thecarrier 30a such as the electrodes 36a and 36b shown in Figure 6 with its counterpartelectrodes shown in Figure 6 as being arranged on an opposite end of the carrier 30a. The} electrodes 36 may comprise stimulation electrodes 36a and a microheating structure 36b, the stimulation electrodes 36a corresponding to electrodes 26 as described with respect to Figure 5a above. The microheating structure 36b may comprise a circular portion encircling a perimeter of the electrode 36a, and a linear portion 36c extending radially with respect to the electrode 36a._{Referring to Figure 6a, a cross sectional view along lines 6a – 6a of Figure 6 as schematically} shown. According to the schematic cross-sectional view, a stacked arrangement of the microheating structure 36b, the electrode 36a and the carrier 30a is schematically shown. Herein, the electrode 36a is schematically shown as a line element, however, this does not_{impose any limitation and it is understood that the element 36a shown in Figure 6a corresponds} to a cross section through a track line of a spiral wound shape. The microheating structure 36b may be formed of a positive temperature coefficient (PTC) material or carbon-conductive material. For example, it may be arranged in thermal contact with a layer of a material having a relatively high thermal conductivity, more preferably having_{a thermal conductivity of at least 1 W/(m K), such as more than 2 W/(m K) or more than 5W/(m K) or more than 10 W/(m K) or more than 20 W/(m K) or more than 50 W/(m K). However,this does not impose any limitation and the microheating structure 36b may only be in contact} with the electrode 36a which may act as a heat spreading layer in addition to it’s electrical function._{However, this does not impose any limitation on the present disclosure and the person skilled} in the art will appreciate that the microheating structure 36b and the electrode 36a may be arranged on opposite surfaces of the carrier 30a._{Referring to Figure 6b, a cross sectional view along line 6b-6b as schematically illustrated} showing a conductive track line 34a formed on the surface of the carrier 30a. Accordingly, the conductive track line 34a may be formed on the same surface as at least the micoheating structure 36b._{Referring to Figure 7, a flexible circuit structure 40 in accordance with some illustrative} embodiments of the present disclosure is schematically illustrated in a top view. The flexible circuit structure is formed of conductive tracks 44 and electrodes 46a to 46d provided in a surface of a carrier (not illustrated), together with connection terminals 45 formed in the surface of the carrier (not illustrated). The electrodes 46a to 46d are connected with respective_{connection terminals of the connection terminals 45 by means of respective conductive tracks} of conductive tracks 44. Optionally, an LED component 48 in accordance with the LED_{component 8 described above with respect to Figures 1 and 1a may be included.} The electrodes 46a to 46d may implement different sensor functions and electrode 46a may_{be configured as an electrostimulation electrode similar to the electrodes 26a and 36a asdescribed above, while electrode 46b may be configured as an exudate electrode. The} electrode 46c may be configured as a pH electrode and the electrode 46d may be configured as another pH electrode. For example, the exudate electrode may encircle a perimeter of the electrostimulation electrode 46a, while the pH electrodes may be arranged at positions_{corresponding to 12:00, 3:00, 6:00 and 9:00 around the perimeter of the electrostimulation} electrode 46a. The pH measurement may be achieved via measurement between a reference electrode and a pH sensitive layer implemented in each of electrode 46c and 46d. For example, any of the pH electrodes 46c and 46d may use electrical potential to measure_{the pH of a solution where each electrode works by comparing the electric potential of a pH-sensitive system to the potential of a stable reference system. For example, each electrodemay be implemented as an electrode system using a pH-sensitive electrode arrangementconfigured for changing voltage proportionally to the concentration of hydrogen ions, includinga sensing electrode for measuring an electric potential. For example, the sensing electrodemay be filled with a potassium chloride (KCl) solution which conducts electricity between pH-sensitive glass and the sensing electrode. Furthermore, the pH electrodes 46c and 46d mayeach or both be coupled with a reference system separated from each sensing system. Insteadof a pH-sensitive glass, the reference system(s) may use a replaceable reference junctionproviding electrical contact with the sample while protecting the internal system. Unlike pH-} sensitive glasses, the reference junction does not change potential with changing pH. A_{reference electrode measures the potential of the solution. The reference system may be filled} with a refillable silver/silver chloride (Ag/AgCl) solution which conducts electricity between the_{reference junction and the reference electrode. However, this is only for illustrative purposes} only and does not impose any limitation on a specific layout of the electrodes 46c and 46d._{Additionally, the flexible circuit structure 40 of Figure 7 may be also equipped with an antennapattern similar to the antenna pattern 27a and 27b as described above for allowing wirelesscommunication and/or operation of the flexible circuit structure 40. Accordingly, the flexible} circuit structure 40 allows implementation of a smart wearing arrangement including different_{technologies such as pH monitoring, exudate monitoring, and electrostimulation. The carrier} may be provided as / or on a patch with temperature sensitive substrate and conductive track_{lines and/or electrodes may be formed on the basis of silver chloride ink or any other} conductive ink as described with respect to the first and second aspects in the description above. Further referring to Figure 7, additional pH electrodes may be distributed over the carrier between the electrostimulation electrodes 46a, thereby increasing a spatial resolution of pH measurement over an area of the flexible circuit structure 40._{Referring to Figure 8, a flexible circuit structure 15 in accordance with some illustrative} embodiments of the present disclosure as schematically illustrated. The flexible circuit structure 50 may comprise a carrier 50a which may correspond to the carrier 2 as described_{above with respect to Figure 1. Furthermore, conductive tracks 54, connection terminals 55and electrodes 56, e.g., electrode 56a and 57b may be provided. Additionally, a microchannel} structure 57 having at least one microchannel 57a as formed in the surface of the carrier 50a, the microchannel structure 57a accommodating electrodes 57b. Furthermore, the flexible_{circuit structure 50 comprises an LED component 58 similar to the LED component 8 asdescribed above with respect to Figure 1. Microchannel structure 57a is formed in the surface} of the carrier 50a for guiding a liquid or fluid secreted from a skin of a user into one or more inlets at the electrodes 57b for implementing an electrochemical sensor, the microchannel structure 57a having one or more holes that connect to at least one channel of the microchannel structure 57a and provides one or more inlets, as well as a reservoir intersecting_{the microchannel structure 57a, wherein electrodes 57b are aligned with the reservoir of the} microchannel 57a and communicates with microchannel structure 57a via the one or more holes. Furthermore, outlet holes are provided at the microchannel structure 57a for draining fluid collected by the microchannel structure 57a. In some illustrative embodiments, the microchannel structure 57a may be formed of interconnected channels, for examples linearly extending channels and semi or complete circularly shaped channels or any other curved channel portion. Conductive track lines may extend between the electrodes 57b and the respective ones of the connection terminals 55, similar to the electrode 56a being coupled to a respective ones of the connection terminals 55 by according conductive track lines._{Referring to Figure 8, the microchannel structure 57a comprise microchannels providingpathways that guide a fluid to one or more dedicated (or corresponding) conductive tracks ofthe conductive tracks, thereby allowing a dedicated sensing function implemented by theseconductive tracks. The microchannel structure 57a is comprised of a microfluidic systemformed on the carrier 50a. The microfluidic system may further comprise microchannels for} implementing tiny channels, reservoirs, valves, and sensors with the function of controlling_{fluids in confined spaces on the carrier when employing the flexible circuit structure in fluid} detection applications. For example, the microfluidic system providing the microchannel structure 57a may be provided on the carrier 50a by laminating a layer (e.g., PET) onto at least a portion of a surface_{of the carrier and patterning the laminated layer into a line pattern to define the microfluidic} system on the surface of the carrier 50a such that one or more microchannels of the microchannel structure 57a are defined in or on the surface of the carrier 50a. The microchannels of the microchannel structure 57a may herein be formed by a laminated layer pattern or laminated line pattern on the surface of the carrier (e.g., PET and an adhesive or other bonding of PET on the carrier after/for lamination) and/or recesses formed in surface of the carrier 50a. Within at least one microchannel, e.g., a microchannel having a reservoir portion with increased channel width compared to the rest of the microchannel (as shown in Figure 8 by a reservoir accommodating electrode(s) 57b), a transducer of a biosensor may be provided. For_{example, at least one electrode 57b of the transducer may be formed within at least onemicrochannel of the microchannel structure 57a (e.g., by at least partially routing an electricallyconductive material in the at least one microchannel and forming an electrode at a routed linewithin the at least one channel such as in the reservoir of Figure 8). A bioreception material,such as a membrane material, may be formed on the electrode(s) 57b in the reservoir (e.g.,by cross linking the bioreception material on the electrode(s) 57b). For example, theelectrode(s) 57b comprising one or more noble metal electrodes (such as one or more gold} electrodes)._{As indicated above and in accordance with some special illustrative examples, the at least one} microchannel of the microchannel structure 57a may be covered at least at the reservoir by a_{covering system (not illustrated in the view of Figure 8 for ease of illustration of the electrode(s)57b) at the electrode(s) 57b. The covering system (not illustrated) may be formed over wallsof the microchannel at least at the reservoir such that a cavity around the electrode(s) 57b forreceiving a biofluid (not illustrated) subject to detection is formed at least at the location of theelectrode(s) 57b.Referring to Figure 9a, an illustrative example of a smart wearing arrangement based on theflexible circuit structure 50 of Figure 8 as schematically shown, the smart wearing arrangement50’ comprising a carrier 50a’ having electrodes 56 and a microchannel structure 57 an} electrochemical sensor arrangement formed thereon. The microchannel structure 57 may be formed in a lower surface LS of the carrier 50a’, a lower surface LS being indicated as a surface_{of the smart wearing arrangement 50’ to be brought into mechanical contact with the skin of a} user of the smart wearing arrangement 50’._{Referring to Figure 9b, a top view on an upper surface US opposite the lower surface LS ofFigure 9a of the carrier 50a’ as schematically illustrated, the upper surface US having a module} 55a provided with a module connection terminal 59 for coupling the module 55a to connection_{terminals (not illustrated) of the carrier 50a’ formed thereon. Electrode 56 may be provided aselectrodes formed on only one surface of the carrier 50a’, however, this does not impose anylimitation and the electrodes 56 may either be formed as electrodes formed on either side ofthe carrier 50a’, i.e., the lower surface LS and the upper surface US, as well as possible being} implemented as one or more electrodes 56 extending along a thickness of the carrier 50a’_{being exposed at both surfaces. The smart wearing arrangement 50’ may be implemented asan active part arrangement or as a passive part arrangement as described above with respectto other embodiments of the present disclosure. The carrier 50a’ may be attached to a patch} for implementing a smart bandage. In accordance with some illustrative examples, the microchannel structure 57 may comprise linearly extending channels, for examples arranged in an interconnected star arrangement, outer ends of the channels being interconnected by an encircling channel, while inner ends of the linearly extending channels couple to a cavity. The cavity may be centered within an area encircled by the outer encircling channel or may be asymmetrically arranged within this area. The outer encircling channel may at least partially encircle the linearly extending channels, e.g., completely encircling as shown in Figure 9a. Referring to Figures 9a and 9b, the microchannel structure 57a comprise microchannels_{providing pathways that guide a fluid to one or more dedicated (or corresponding) conductivetracks of the conductive tracks, thereby allowing a dedicated sensing function implemented by} these conductive tracks. The microchannel structure 57a is comprised of a microfluidic system formed on the carrier 50a’. The microfluidic system may further comprise microchannels for implementing tiny channels, reservoirs, valves, and sensors with the function of controlling_{fluids in confined spaces on the carrier when employing the flexible circuit structure in fluid} detection applications._{With respect to Figure 10, an enlarged portion of the electrochemical sensor arrangement ofFigure 8 is schematically shown.As shown in Figure 10, a carrier having conductive tracks lines 54, connection terminals 55} and a microchannel structure 57’ for implementing an electrochemical sensor (electrode)_{formed in a main surface of the carrier may be provided. The microchannel structure 57’ haschannels 57a’ comprising two linearly extending microchannels continuously connected withan intermittent semicircular channel portion formed in the surface of the carrier. Themicrochannel structure 57’ accommodates conductive track lines 57b’ and 57c’ routed partiallyin the channels and outside the channels. The microchannel structure 57’ is formed in the} surface of the carrier for guiding a liquid or fluid secreted from a skin of a user into one or more inlets for implementing an electrochemical sensor, the microchannel structure 57’ having one_{or more holes that connect to at least one channel of the microchannel structure 57’ and} provides one or more inlets, as well as a reservoir intersecting the microchannel structure 57’,_{wherein electrodes are aligned with the reservoir of the microchannel structure 57’ andcommunicates with microchannel structure 57’ via the one or more holes. Furthermore, outletholes are provided at the microchannel structure 57’ for draining fluid collected by the} microchannel structure 57’. With respect to the electrochemical sensor described above in the context of Figures 8 to 10, only illustrative examples are disclosed without imposing limitation of the present disclosure. Generally, an electrochemical sensor in any of Figures 8 to 10 may be embodied as a sensor_{configured for quantitative analysis of biofluid, such as sweat, by possibly including direct} sampling and detection of multiple biomarkers without evaporation. For example, the carriers employed herein may at least partially have material portions relied on absorbent pads or fabric_{substrates configured for adhering to the skin of a user for accumulating biofluid, such as} sweat. For example, any of the carriers described in the context of Figures 8 to 10 may be_{implemented as a skin-interfaced soft microfluidic system that captures and stores biofluid,such as sweat, on the surface of the subjects' skin. For example, a microchannel portion may} be provided so as to implement a (wireless, where an antenna pattern is additionally provided) microfluidic device to capture and store sweat to channel(s) of the microfluidic device. For_{example, the microchannels may be provided in harvesting areas of a main surface of the} carrier, e.g., by forming a polydimethylsiloxane (PDMS) microfluidic channel layer on the_{carrier in harvesting areas (~ 10 mm2). A conformal contact of an adhesive layer may allow a} volumetric harvesting in an illustrative amount of ~ 1.2 to 12 µL/hour (without limitation)._{In some other illustrative examples, a microfluidic system may include a plurality (at least two)separated channels having one serpentine channel (e.g., width 1.0 mm; height 300 µm) formedfor measuring how much biofluid is excreted, while other channels may be formed forquantitative colorimetric assays occurring, for example, in a 4 mm diameter and ~ 200 μmdepth of chamber in the middle of the channel (e.g., a cylindrical chamber).In some other illustrative examples, a microfluidic system may include a network of} microchannels in a sequential manner. For example, the system may have 400 µm thickness,_{200 µm channel width, 300 µm channel height in a circular overall design, e.g., of 3 cmdiameter. Another microfluidic network of a more complicating structure may be consideredhaving a combined effect of different mechanism of a valve system through a double layer ofmicrofluidics for enabling time-sequential biofluid sampling with instant quantitative assayeliminating any possibilities of mixing the sampled biofluid with biofluid flow in the microfluidics.Referring to Figure 11, a simplified side (cross-section) drawing of a flexible circuit structure60 according to some illustrative embodiments of the present disclosure is shown. The flexible} circuit structure 60 may be implemented as a double-sided flexible circuit structure comprising_{a carrier 62 and a conductive adhesive 64, e.g., a solder. The conductive adhesive 64 mayserve for attaching a plurality of components 67a, 67b, 67c, 67d to the carrier 62 on opposing} first and second surfaces of the carrier 62, the first and second surfaces representing two opposing main surfaces of the carrier 62 such as a surface facing a skin of a user during use of the flexible circuit structure 60 (a bottom surface in the illustration of Figure 11, that is a surface on which components 67c and 67d are arranged), while components 67a, 67b, and_{67c are arranged on a surface facing away from a user during use of the flexible circuitstructure 60. The flexible circuit structure 60 may further comprise an optional encapsulant 65over one or more of the components 67a to 67d and conductive tracks (not illustrated) and} connection terminals (not illustrated)._{In some illustrative examples herein, the carrier 62 may be a substrate material portionrepresenting a flexible substrate comprised of flexible materials such as polymeric materialsincluding but not limited to, polyethylene terephthalate film (PET), polyethylene naphthalate} (PEN), polyimide foil (PI), polypropylene, polyethylene, polystyrene, polycarbonate, polyether_{ether ketone (PEEK), or any of a variety of polymer films or combinations thereof. However,this does not impose any limitation and, in an alternative example, the carrier 62 may include} one or more portions that are rigid and comprise one or more of glass, wood, metal, PVC, silicon, epoxy resin, polycarbonate, or any of a variety of rigid materials or combinations_{thereof. In yet another example, the carrier 62 may include a combination of one or more} flexible materials described herein and one or more rigid materials described herein._{The conductive tracks (not illustrated) may be printed or formed by photolithography and} etching techniques or selective deposition techniques on one or more main surfaces of the_{carrier 62. In some examples herein, the conductive tracks (not illustrated) may comprise aconductive material such as a metal material or a material containing metallic particles such} as, for example, but not limited to, silver, platinum, palladium, copper, nickel, gold, or aluminum or carbon or conductive polymer, or some combination thereof. In some aspects, the_{conductive tracks (not illustrated) may include metallic particles and one or more chemical} additives (e.g., solvents, binders, and the like) that improve one or more features of the conductive traces (e.g., flexibility stretchability, solderability, or the like). The conductive metals_{or composites may be flakes, fine particulates, or nano-particulates, or combinations thereof,} in some embodiments._{In some illustrative embodiments, intricate patterns of the conductive tracks (not illustrated)may be selectively printed or otherwise deposited to form circuit tracks by any of a variety of} printing or additive deposition methodologies, including, for example, any form of gravure, flatbed screen, flexography, lithography, screen, rotary screen, digital printing, inkjet printing,_{aerosol jet printing, 3-D printing, and like print methods, or combinations thereof. In someexamples, the conductive material may be in the form of a printable conductive ink, toner, orother coating. The electronic inks may include non-conductive particles or particulates that are} included to mechanically pierce or penetrate a native oxide formed on a metallic surface and thereby create a low-resistance electrical contact between the metallic surface and the electronic ink. In some such examples, the non-conductive particles may have a surface that includes features useful for piercing the oxidized metallic surface. In other examples, the conductive particles may have a surface that includes features useful for piercing the oxidized metallic surface. In some examples, the ink includes solvents and/or binders to assist with removing or penetrating the native oxide layer to expose a non-oxidized aluminum surface._{In some special illustrative but non-limiting example, silver ink may be thermally cured, such} that electrical testing after completion of the cure process provides a mechanically and low electrical resistance between the silver ink and metallic surface. In some other special illustrative but non-limiting example, a fabrication process may be provided, the fabrication_{process including printing silver ink directly onto an oxidized metallic surface to form a} mechanically strong and electrically low-resistance interconnect to form an electrical circuit._{With ongoing reference to Figure 11, at least some of the components 67a to 67d may beattached to the carrier 62 using low temperature solder as the adhesive 64. The components67a to 67d may comprise at least one component element out of, for example, resistors,capacitors, inductors, transistors, flat no-leads packages, one or more LEDs, microcontrollers,} sensors, or connectors, etc, and/or modules comprising at least one of the aforementioned_{component elements. Any component element, preferably of a relatively low profile form factor,may conceivably be attached to the carrier 62, either permanently using the conductive} adhesive 62 or releasably by a releasable mechanism (not illustrated)._{In some aspects, the encapsulant 65 may be placed over at least some of the components} 67a to 67d which are not to be brought into mechanical contact with an external body (not illustrated) and/or which are not to be releasably mounted to the carrier 62 and/or which are to be protected against environmental conditions, e.g., humidity etc. The encapsulant 65 may at least one of protect, insulate, and mechanically secure at least one of the components 67a to_{67d on the carrier 65.} The process schematically shown in FIG.12 comprises a first step of depositing conductive_{tracks, optional contact pads, connection terminals, and one or more electrodes, e.g., made of} a conductive material such as a metal, for example copper or copper-based alloy, silver or silver-based alloy, gold or gold-based alloy, aluminum or aluminum-based alloy, or a mixture of at least one of these, on the substrate formed by the carrier strip._{These are, for example, produced by means of photolithography of a conductive material layer} bonded and/or laminated to the substrate or of a layer originating from deposition of a_{conductive material, such as electrodeposition. They may also be deposited by lamination or} screen printing._{In the case of bonding or of lamination, a reel 72 may initially feed or supply a sheet 74 ofconductive material to the process such that the sheet 74 may itself come from the reel 72which is rolled off and applied continuously to a carrier strip 73 rolled off reel 71.In some illustrative examples, bonding may be carried out using conventional techniques forproducing flexible electronic circuits and, for example, an adhesive may be of two types: aliquid (the gluing process then taking place via coating using a roller or a slot) or in the form ofa film (the bonding process then taking place via lamination).} After bonding, a curing step may be carried out at a temperature that may range from about_{20°C to about 120° C.In some illustrative examples herein, the thickness of the sheet 74 may be conventionally} chosen to be between about 10 μm and about 500 μm, preferably between about 10 μm and_{about 200 μm or between about 10 μm and about 100 μm, more preferably between about 10μm and about 20 μm, such as between about 12 μm and about 18 μm.Next, as shown in Figure 12, the process may comprise producing conductive tracks on thesheet 74. For example, the process may use a photolithography process which uses a step 76of putting a photoresist and a mask in place, a step 77a of exposing the unmasked portions of} the photoresist to radiation, dissolving the exposed portions of the photoresist followed by a_{chemical attack 77b which removes the portions of conductive material of the sheet 74 fromregions which are no longer covered by photoresist. However, this does not impose any} limitation and, alternatively, at least one of conductive tracks, contact pads, connection_{terminals, and electrical contact lands may also be mechanically cut out, e.g., to form a} conductive grid which may then be roll-bonded to carrier strip 73 of the stacking of sheet 74 and 73 forming a bonded strip of sheets 73 and 74._{Once an electrical circuit has been patterned on the sheet 74, the process may optionallycontinue with deposition 78 of an optional protective coating, e.g., a layer of nickel with orwithout phosphorus, on the conductive tracks so as to protect them from oxidation. Thisprotective coating may be deposited using electrodeposition or autocatalytic deposition. Forexample, the protective coating may have a thickness that affords adequate corrosionresistance, e.g., between about 1 μm and about 10 μm or between about 2 μm and about 5} μm._{Next, the process of the application may comprise application 79 of masking means 79a to thetrack-side of the bonded strip of sheets 73 and 74 which may leave at least one of contactpads, electrode regions, and connection terminals of the band exposed. Then, selectivedeposition 80 of a layer of noble metal on said at least one of exposed contact pads, electroderegions, and connection terminals through the masking means 79a may occur. For example,} selective deposition of gold with a thickness from 1 to 100 nanometers, for example performed using electrodeposition or autocatalytic deposition, makes it possible to obtain connection_{regions of low electrical resistance and with resistance to oxidation. A number of solutions maybe used to produce the masking means 79a. For example, these means 79a may comprisecut-outs 79b which leave contact pads and/or electrodes and/or connection terminals exposedto allow selective deposition of noble metal thereon. For example, the masking means 79a} may consist of a film provided with openings allowing selective deposition of the noble metal or they may also consist of an inlay provided with openings allowing selective deposition and applied to the strip as it moves into an electrolytic bath or onto a deposition liquid applicator._{Additionally, the masking means 79a may consist of a tool, for example a plastic tool forming} a stencil, provided with cut-outs leaving the contact pads and electrodes exposed, which is_{placed on the strip and applied to the tracks of the carrier strip at a station for depositing thenoble metal. In some illustrative examples, the masking means 79a may also consist of a} masking strip made of foam applied to the strip and provided with said cut-outs leaving the contact pads and electrodes exposed._{The masking means 79a may be positioned in the manufacturing process so as to perform} selective deposition through application to the strip as it moves into an electrolytic bath or onto_{a deposition liquid applicator, the openings leaving the contact pads and/or electrodes} exposed._{The steps of the process may be carried out continuously in succession on the rolled-off carrierstrip 73. The manufacturer producing the carrier strip 73a forming the flexible circuit structuresto produce the bands may then punch unneeded segments of the tracks (e.g., test tracks) androll the carrier strip 81 with its flexible circuit structures back onto a reel 72’ for potential storage} before delivery to the company which performs the step of depositing the biosensor on the bands or for internal transfer to a production line suitable for handling biological products in order to finish the bands._{In subsequent process steps, the flexible circuit structures on the carrier strip 81 may beprovided with one or more biosensors in case that a smart bandage having one or morebiosensors is to be prepared. To that end, the carrier strip 81 may be rolled off the reel 72’again to carry out the deposition 84 of bioactive material on electrodes using a deposition} device 83. The bioactive material may, for example, be an enzyme suitable for measuring_{glucose in the treatment of diabetes. After the deposition 84, one or more lamination stepsmay be carried out and the bands 88 may be separated in one or more cutting steps 85, 86,for example by means of a first cutter blade at step 85 which separates flexible circuit structuresprovided as, for example, band panels and a punch at step 86 which trims the flexible circuit} structures in a desired shape, e.g., a band._{The above-described process may provide an optimized solution for the mass production of} smart wearing arrangement, such as smart bandages having one or more biosensors, in particular in the context of a reel-to-reel process, and a decrease in the amount of gold or of noble metal required for this manufacture. In some illustrative embodiments described herein, the carrier strip 81 may represent at least one of the flexible circuit structures in the stages illustrated in and described above with respect any of Figures 1 to 10 above. For example, the cutting steps 85 and 86 may comprise a cutting along at least one cutting line, e.g., the cutting line CT shown in Figure 2. Although the embodiments shown in Figures 1 and 3 to 10 do not explicitly describe cutting_{lines, the person skilled in the art will appreciate that this does not impose any limitation and} the description of cutting line CT in the context of Figure 2 may be applied to each of the embodiments described above with respect to Figures 1 and 3 to 10, as well. In illustrative embodiments as described above with respect to Fig. 1 to 13, flexible circuit structures may be provided for implementing transducers of biosensors. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately” and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language_{indicates otherwise. “Approximately” or “substantially” as applied to a particular value of a} range applies to both values, and unless otherwise dependent on the precision of the_{instrument measuring the value, may indicate +/- 10% of the stated value(s).}

Claims

Claims_{1. A flexible circuit structure, comprising:} a carrier of a flexible insulating material, preferably a carrier strip; conductive tracks and one or more electrodes formed on at least one of a first surface of the carrier and a second surface of the carrier opposite the first surface; connection terminals formed on the first surface and electrically coupling to the one or more electrodes via at least some of the conductive tracks; and a fluid collector system formed on the carrier, the fluid collector system comprising at least one microchannel formed in the second surface, wherein at least one of the conductive tracks is formed so as to at least partially extend within the at least one microchannel._{2. The flexible circuit structure of claim 1, wherein at least one of:} the fluid collector system is coupled with a pH sensor and/or a sweat sensor and/or an Na+ sensor; at least one microchannel is provided in a semicircular or circular or elliptical or spiral or sigma-shaped pattern; and/or the flexible circuit structure comprises the carrier having a short microfluidic pathway implemented by the one or more microchannels configured for guiding sweat appearing on skin of a user to a small space in the surface of the carrier._{3. The flexible circuit structure of claim 1 or 2, further comprising an LED component} arranged on the first surface, the LED component connected to two or more of the connection terminals by conductive tracks routed on the first surface between the LED component and the two or more connection terminals._{4. The flexible circuit structure of claim 3, further comprising an electric module having a} microchip, the electric module being releasably coupled to the connection terminals._{5. The flexible circuit structure of claim 4, wherein the electric module further comprises an electric power supply for powering the flexible circuit structure, the flexible circuit} structure being configured as an active circuit structure._{6. A flexible circuit structure, comprising:} a carrier of a flexible insulating material, preferably a carrier strip; conductive tracks and one or more electrodes formed on at least one of a first surface of the carrier and a second surface of the carrier opposite the first surface; connection terminals formed on the first surface and electrically coupling to the one or more electrodes via at least some of the conductive tracks; an electric module having a microchip, the electric module being releasably coupled to the connection terminals; and an LED component arranged on the first surface, the LED component connected to two o_{r more of the connection terminals by conductive tracks routed on the first surface} between the LED component and the two or more connection terminals, wherein the two connection terminals in contact with the LED component are not interconnected such that an open circuit is provided with respect to the LED component and the conductive tracks routed between the LED component and the two connection terminals, the open circuit being closed by the electric module coupled to the connection terminals._{7. The flexible circuit structure of claim 6, wherein the electric module further comprises} an electric power supply for powering the flexible circuit structure, the flexible circuit structure being configured as an active circuit structure._{8. The flexible circuit structure of claim 6 or 7, further comprising a fluid collector system} formed on the carrier, preferably on the second surface, the fluid collector system comprising at least one microchannel formed in the second surface._{9. The flexible circuit structure of claim 8, wherein at least one of:} the fluid collector system is coupled with a pH sensor and/or a sweat sensor and/or an Na+ sensor; at least one microchannel is provided in a semicircular or circular or elliptical or spiral or sigma-shaped pattern; at least one of the conductive tracks may be formed so as to at least partially extend within the at least one microchannel; and/or the flexible circuit structure comprises the carrier having a short microfluidic pathway implemented by the one or more microchannels configured for guiding sweat appearing o_{n skin of a user to a small space in the surface of the carrier.10. The flexible circuit structure of one of claims 1 to 9, wherein the carrier comprises a substrate, preferably a substrate made of PET and/or PI and/or VEP, laminated with a conductive material sheet, the conductive material sheet being patterned into a routing pattern providing the conductive tracks, wherein the flexible circuit structure comprises} at least two electrodes configured as electrodes adapted to performing one of e_{lectrochemistry measurement and chemiresistive measurement or as electrodes comprising an organic electrochemical transistor system.11. The flexible circuit structure of claim 10, wherein the conductive material sheet} comprises at least one of copper, aluminum, silver, gold, a noble metal, and a platinum group metal._{12. The flexible circuit structure of claim 10 or 11, wherein the routing pattern is formed of} the patterned conductive material sheet, such as a copper sheet, wherein the patterned conductive material sheet is plated with at least one of gold, silver, and platinum group metal(s)._{13. The flexible circuit structure of one of claims 10 to 12, wherein the electrodes are} arranged on the substrate or integrated into the substrate having at least one electrode surface being exposed with respect to the substrate._{14. The flexible circuit structure of claim 13, wherein the at least one exposed electrode} surface being covered by a membrane configured for diffusion of an analyte to be detected by the electrode through the membrane, such as at least one of glucose, lactate, Ketone, and creatinine._{15. The flexible circuit structure of claim 13, wherein the substrate further comprises a} microfluidic system at least partially in fluid communication with the routing pattern._{16. The flexible circuit structure of one of claims 1 to 15, wherein the one or more electrodes} comprise at least one stimulation electrode arranged on the carrier in a substantially spiral routing._{17. The flexible circuit structure of claim 16, wherein the at least one stimulation electrode} is arranged on the second surface, the at least one stimulation electrode being connected to conductive tracks by via connections extending through the carrier between the first and second surfaces._{18. The flexible circuit structure of one of claims 1 to 17, further comprising at least one pH} sensor and/or at least one exudate sensor arranged on carrier._{19. The flexible circuit structure of claim 18 in combination with claim 16 or 17, wherein the} at least one pH sensor and/or at least one exudate sensor is arranged with respect to the at least one stimulation electrode such that the at least one pH sensor is arranged within an area covered by at least one stimulation electrode and/or the at least one exudate sensor is arranged on a perimeter around the at least one stimulation electrode._{20. The flexible circuit structure of one of claims 1 to 19, wherein the flexible insulating material comprises at least one of polyetherimide (PEI), polyethylene terephthalate} (PET), polyethylene naphthalate (PEN), polyimide (PI), a glass-epoxy composite, and a cellulose material._{21. The flexible circuit structure of one of claims 1 to 20, further comprising an adhesive} layer formed on one surface of the carrier, the conductive tracks preferably being formed only on the first surface of the carrier and the adhesive layer preferably being at least partially formed on the second surface_{22. The flexible circuit structure of one of claims 1 to 21, wherein the conductive tracks are} formed of a conductive material comprising at least one of silver, copper, and gold._{23. The flexible circuit structure of one of claims 1 to 22, wherein the carrier is arranged on} a base material comprising at least one of silicone, acrylate, hydrocolloid, synthetic b_{ased rubber, and medical tape so as to provide a wearable arrangement, such as a} bandage, preferably a gauze bandage, such as an adhesive bandage or an elastic bandage._{24. The flexible circuit structure of one of claims 1 to 23, wherein the conductive tracks} comprise at least two conductive tracks electrically coupling at least two of the connection terminals with a sensor element, preferably an oxygen sensor element, the conductive tracks routed between the two terminals and the oxygen sensor element in a _{curvy routing pattern having at least one routing portion of at least partially a wavy or} sinusoidal shape._{25. The flexible circuit structure of claim 24 in combination with claim 6 or 3, wherein the} LED component and the sensor element are arranged on the first surface._{26. The flexible circuit structure of one of claims 1 to 25, further comprising a microheating} structure arranged on at least one of the first and second surfaces, wherein the microheating structure is configured to heat the microheating structure to a temperature in a range from about 36°C to about 90°C._{27. The flexible circuit structure of claim 26 in combination with claim 16 or 17, wherein the} microheating structure is arranged on the carrier so as to at least partially enclose the at least one stimulation electrode on the carrier, the microheating structure preferably being formed by a positive temperature coefficient (PTC) material or carbon-conductive material and/or the microheating structure being preferably arranged in thermal contact with a layer of a material having a relatively high thermal conductivity, more preferably h_{aving a thermal conductivity of at least 1 W/(m K), such as more than 2 W/(m K) or more than 5 W/(m K) or more than 10 W/(m K) or more than 20 W/(m K) or more than 50 W/(m K).28. The flexible circuit structure of one of claims 1 to 27, wherein a subset of the conductive} tracks are routed on the first surface so as to form at least one antenna loop portion operable in a frequency range starting from about 1 kHz to about 10 GHz._{29. The flexible circuit structure of one of claims 1 to 28, wherein the flexible circuit structure} is configured as a passive circuit structure._{30. The flexible circuit structure of one of claims 1 to 29, wherein the carrier has a cutting pattern provided on the first surface, the cutting pattern defining at least one line not} extending across the conductive tracks, the cutting pattern being configured such that, upon cutting the carrier along the at least one line, two carrier material portions separated by the at least one line are displaceable with respect to each other._{31. The flexible circuit structure of one of claims 1 to 30, wherein the connection terminals} are arranged at a geometric center of the first surface and/or the connection terminals are arranged in a pattern with one or more substantially parallel lines of terminals._{32. A bandage, for example a patch, comprising a flexible circuit structure of one of claims} 1 to 31._{33. A transducer for a biosensor, comprising the flexible circuit structure of one of claims 1} to 31._{34. A method of fabricating a flexible circuit structure, comprising:} providing a carrier of a flexible insulating material, preferably a carrier strip; forming conductive tracks and one or more electrodes on at least one of a first surface of the carrier and a second surface of the carrier opposite the first surface; and forming connection terminals on the first surface and electrically coupling to the one or more electrodes via at least some of the conductive tracks._{35. The method fo claim 34, wherein the flexible circuit structure of one of claims 1 to 31 is} formed._{36. The method of claim 34 or 35, further comprising providing a pattern of cutting lines, wherein cutting lines of the pattern of cutting lines partially extending between some of the conductive tracks, preferably the method further comprising cutting the pattern of} cutting lines, the method more preferably further comprising separating the flexible s_{ubstrate structure along the pattern of cutting lines such that portions of the carrier separated by cutting lines are spaced apart with a carrier-free portion extending} therebetween._{37. The method of one of claims 34 to 36, wherein the flexible substrate of one of claims 1 to 22 is formed and/or the method further comprising integrating the flexible circuit} structure into a bandage, for example a patch.