HIGH RELIABILITY ANALYTE SENSORTECHNICAL FIELDThe invention mainly relates to the field of medical devices, in particular to a high reliability analyte sensor.
BACKGROUNDThe pancreas in a normal human body can automatically monitor the level of glucose in the human blood and automatically secrete the required insulin/glucagon. In diabetics, the pancreas does not function properly and cannot produce the insulin the body needs. Therefore, diabetes is a metabolic disease caused by abnormal pancreatic function, and diabetes is a lifelong disease. At present, there is no cure for diabetes with medical technology. The occurrence and development of diabetes and its complications can only be controlled by stabilizing blood glucose.
Diabetics need to have their blood glucose measured before they inject insulin into the body. At present, most of the testing methods can continuously measure blood glucose and send the data to a remote device in real time for the user to view. This method is called Continuous Glucose Monitoring (CGM) . The method requires the device to be attached to the skin and the probe it carries is penetrated into the tissue fluid beneath the skin.
However, the electrode of the sensor may be broken when the substrate is repeatedly bent during the use process, which affects the service life of the sensor and reduces the detection reliability of the sensor.
Therefore, the existing technology urgently needs an analyte sensor with long service life and high detection reliability.
BRIEF SUMMARY OF THE INVENTION
In view of the shortcomings of the above prior art, the embodiment of the invention discloses a highly reliability analyte sensor. The electrode is distributed on the surface of the in vivo part in a predetermined manner to avoid the easy-bending-area on the substrate. When the substrate is repeatedly bent, the possibility of electrode breaking is reduced. At the same time, at least one layer of insulating material is post manufactured at least one area on the substrate to avoid the area where the PAD and electrode are located, the mechanical strength of the substrate of sensor is increased. After the sensor is penetrated into the subcutaneous skin, when it bends with the muscle creep, the time for the substrate to reach the limit fatigue is extended, thus prolonging the service life of the sensor and improving the detection reliability of the sensor.
The invention discloses an analyte sensor, which comprises: at least one layer of substrate, the substrate includes an in vivo part and an in vitro part. At least two electrodes are arranged on the surface of the in vivo part for penetrating into the subcutaneous to obtain analyte parameter information. And PADs, which are arranged on the surface of the in vitro part and are electrically connected with the corresponding electrodes through wires. The electrodes are distributed on the surface of the in vivo part in a predetermined manner to avoid the easy-bending-area on the substrate. Wherein, at least one layer of insulating material is post manufactured at least one area of the substrate, and the insulating material avoids the central conductive area of the PADs and electrodes.
According to one aspect of the invention, the easy-bending-area includes at least the middle section of the in vivo part.
According to one aspect of the invention, it also includes a protective layer arranged on the substrate surface, and the protective layer covers at least the edge of the electrode.
According to one aspect of the invention, the protective layer also covers the edge of the PAD.
According to one aspect of the invention, the substrate comprises at least two layers of secondary-substrates, and at least one electrode is arranged on the secondary-substrates of different layers.
According to one aspect of the invention, the secondary-substrate of each layer is pasted into a whole after prefabrication.
According to one aspect of the invention, at least one electrode is arranged on the reverse side of the substrate.
According to one aspect of the invention, a PAD corresponding to an electrode arranged on the reverse side of the substrate is arranged on the reverse side of the substrate.
According to one aspect of the invention, the obverse side of the substrate is also provided with a secondary-PAD corresponding to the PAD.
According to one aspect of the invention, the PAD and the secondary-PAD are electrically connected through the side of the substrate.
According to one aspect of the invention, the obverse side and reverse side of the substrate are prefabricated and pasted into a whole.
According to one aspect of the invention, the obverse side and/or reverse side of the substrate further include at least two layers of secondary-substrates, and at least one electrode is arranged on the secondary-substrates of different layers.
According to one aspect of the invention, the secondary-substrate of each layer is pasted into a whole after prefabrication.
According to one aspect of the invention, the electrode comprises at least one group of electrodes of the same name.
Compared with the prior art, the technical scheme of the invention has the following advantages:
The analyte sensor disclosed by the invention has electrodes distributed on the surface of the in vivo part in a predetermined manner, avoiding the easy-bending-area on the substrate. When the substrate is repeatedly bent, the possibility of electrode breaking is reduced. At the same time, at least one layer of insulating material is post manufactured at least one area on the substrate, avoiding the area where the PAD and electrode are located, increasing the mechanical strength of the substrate of sensor. After the sensor is penetrated into the subcutaneous, when bending with muscle peristalsis, the time for the substrate to reach the limit fatigue is extended, thus prolonging the service life of the sensor and improving the detection reliability of the sensor.
Further, after the sensor is manufactured, at least one layer of insulating material is post manufactured at least one area on the substrate of sensor. The insulating material avoids the area where the PADs and electrodes are located, increasing the mechanical strength of the substrate of sensor. After the sensor is penetrated into the subcutaneous skin, when it bends with the muscle creep, the time for the substrate to reach the ultimate fatigue is extended, thus extending the service life of the sensor, and therefore also improves the detection reliability of the sensor.
Further, the electrode is an electrode array composed of electrode units. The original whole electrode is made into a smaller electrode unit and laid on the wire, which can avoid the whole electrode being bent or even broken when the sensor is repeatedly bent with the muscle after penetrating into the subcutaneous skin, extending the service life of the electrode and improving the detection reliability of the sensor.
Further, a protective layer can also be set on the surface of the substrate, which covers the edge of the electrode and/or the PAD to avoid the electrical signal interference caused by the irregular edge warping of the electrode and the PAD edge. At the same time, the protective layer can further enhance the mechanical strength of the sensor substrate and improve the detection reliability of the sensor.
Further, the substrate includes at least two layers of secondary-substrates. At least one electrode is arranged on the secondary-substrates of different layers. The electrode is located on the secondary-substrates of different layers, which can avoid the wire routing. The electrode can be made larger, increase the contact area with analytes, enhance the electrode reaction sensitivity, and improve the detection reliability of the sensor.
Further, the secondary-substrates of different layers can be prefabricated first, that is, the electrodes, wires and PADs are prefabricated on each layer of secondary-substrate, and then pasted and combined into a whole to form a complete sensor. Different from the conventional layer by layer coating process, it can avoid the insulation failure caused by embrittlement due to insufficient consolidation of the substrate material, and further lead to crosstalk between the electrical signals of wires or electrodes, and noise in the detection signal, the detection reliability of the sensor is improved.
Further, at least one of the multiple electrodes is located on the reverse side of the substrate, and the area of the electrode can be set on the single-sided substrate is limited. Setting one or more electrodes on the reverse side of the substrate can make full use of the two sides of the substrate, so the electrode on each side can be larger, increase the contact area with analytes, improve the electrode reaction sensitivity, and improve the detection reliability of the sensor.
Further, the area of one side of the PAD area on the substrate is limited. At least one PAD is set on the reverse side of the substrate to facilitate the electrical connection with the electrode on the reverse side of the substrate through the wire. At the same time, the PAD on the single side of the substrate can be larger, and the PAD with larger area can be better electrically connected with the circuit, making the current conduction more stable and improving the detection reliability of the sensor.
Further, when the PAD is located on the reverse side of the substrate, the secondary-PAD corresponding to the PAD can also be set on the obverse side of the substrate. The secondary-PAD can be connected to the circuit together with the PAD on the obverse side of the substrate, without additional circuit design for the PAD on the reverse side of the substrate, simplifying the complexity of the circuit. At the same time, the PAD on the reverse side of the substrate and the secondary-PAD corresponding to the obverse side of the substrate are connected by conductive materials on the side of the substrate, the PADs and the secondary-PADs can be electrically connected. Different from the conventional process, the scheme of punching holes on the substrate to electrically connect the PADs on the opposite side. The PADs on the opposite side are electrically connected on the side of the substrate without aligning the PADs on the opposite side on the substrate, which simplifies the difficulty of the manufacturing process and improves the yield of the sensor.
Further, the opposite side of the substrate, that is, the obverse side and reverse side of the substrate, can be prefabricated with electrodes, wires and PADs respectively, and then pasted and combined into a whole to form a complete sensor. Unlike the conventional layer by layer coating process, it can avoid insulation failure caused by brittle fracture due to insufficient curing of the substrate material, further causing crosstalk between the electrical signals of wires or electrodes, and noise in the detection signal, the detection reliability of the sensor is improved.
Further, a multi-level base can also be set on the opposite surface of the substrate. The multi-level base can also be prefabricated with electrodes, wires and PADs, and then pasted and combined into a whole to form the front or back of the substrate. Different from the conventional layer by layer coating process, it can avoid the insulation failure caused by brittle crack due to insufficient curing of the substrate material, and further lead to the crosstalk of electrical signals between wires or electrodes, the detection signal is noisy, which improves the detection reliability of the sensor.
Further, the sensor can be equipped with multiple electrodes with the same name, such as two or more working electrodes, two or more counter electrodes, and two or more reference electrodes, to achieve different sensor functions, such as multiple analyte detection, redundant detection, electrode relay use, enhancing electrode detection signal, reducing detection signal noise, and improving the detection reliability of the sensor.
BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is a top view of a planar structure of the sensor according to the embodiment of the invention.
Fig. 2 is side A view of the planar structure of the sensor as an embodiment of Fig. 1.
Fig. 3 is a sectional view of an electrode according to an embodiment of the invention.
Fig. 4 is a schematic diagram of function realization according to the embodiment of the invention.
Fig. 5 is a top view of the sensor with a stepped structure according to the embodiment of the invention.
Fig. 6 is side A view of the sensor with a stepped structure as an embodiment of Fig. 5.
Fig. 7 is a schematic diagram of the sensor having a cylindrical structure according to the embodiment of the invention.
Fig. 8 shows a V-V’ section view of the transducer with a cylindrical structure as an embodiment of Fig. 7.
Fig. 9 is a schematic diagram of a continuous analyte monitoring device according to an embodiment of the invention.
Fig. 10a-Fig. 10o are schematic diagrams of different sensors according to the embodiment of the invention.
DETAILED DESCRIPTIONAs mentioned above, after the analyte sensor of the prior art is penetrated into the subcutaneous skin, the substrate is repeatedly bent with the creep of the muscle, and the electrode set on the substrate is broken with the repeated bending of the substrate. Secondly, the substrate material may be broken or damaged after reaching the limit fatigue, resulting in bare or broken wires, or the electrode attached to the substrate is broken, affecting the service life of the sensor, the detection reliability of the sensor is reduced.
In order to solve this problem, the invention provides a highly reliability analyte sensor. The electrode is distributed on the surface of the in vivo part in a predetermined manner, avoiding the easy-bending-area on the substrate. When the substrate is repeatedly bent, the possibility of electrode breaking is reduced. At the same time, at least one layer of insulating material is post manufactured at least one area on the substrate, avoiding the area where the PAD and electrode are located, increasing the mechanical strength of the substrate of sensor, after the sensor is penetrated into the subcutaneous skin, when it bends with the muscle creep, the time for the substrate to reach the limit fatigue is extended, thus extending the service life of the sensor and improving the detection reliability of the sensor.
Various exemplary embodiments of the invention will now be described in detail with reference to the attached drawings. It is understood that, unless otherwise specified, the relative arrangement of parts and steps, numerical expressions and values described in these embodiments shall not be construed as limitations on the scope of the invention.
In addition, it should be understood that the dimensions of the various components shown in the attached drawings are not necessarily drawn to actual proportions for ease of description, e.g. the thickness, width, length or distance of some elements may be enlarged relative to other structures.
The following descriptions of exemplary embodiments are illustrative only and do not in any sense limit the invention, its application or use. Techniques, methods and devices known to ordinary technicians in the relevant field may not be discussed in detail here, but to the extent applicable, they shall be considered as part of this Manual.
It should be noted that similar labels and letters indicate similar items in the appending drawings below, so that once an item is defined or described in one of the appending drawings, there is no need to discuss it further in the subsequent appending drawings.
In addition, it should be understood that one or more method steps referred to in the invention do not exclude the possibility that other method steps may exist before and after the combined steps or that other method steps may be penetrated between such explicitly mentioned steps, unless otherwise stated. It should also be understood that the combination connection between one or more devices/devices referred to in the invention does not preclude the existence of other devices/devices before and after the said combination devices/devices or the insertion of other devices/devices between the two specifically mentioned devices/devices, unless otherwise stated. And, unless otherwise specified, the serial number of the steps just a convenient tool for identifying the steps, rather than to limit the steps of the order or limit the scope of the invention can be implemented, the relationship of the relative change or adjust, in the case of no substantial changes to technical content, when as well as the category of the invention can be implemented.
Implementation example 1
Planar structure sensor
Fig. 1 is a top view of a planar structure of the sensor according to the embodiment of the invention. Fig. 2 is side A view of the planar structure of the sensor as an embodiment of Fig. 1.
The sensor 11 comprises a substrate 111, which is divided into an in vitro part X and an in vivo part Y by the dotted line shown in Fig. 1. The in vivo part Y is paved with electrodes, comprising at least one working electrode 1131 and at least one additional electrode. Obviously, in this embodiment, the additional electrode comprises a counter electrode 1231 and a reference electrode 1331, thus forming a three-electrode system. The counter electrode 1231 is the other electrode relative to the working electrode 1131, forming a closed loop with the working electrode 1131, so that the current on the electrode can be normally conducted, the reference electrode 1331 is used to provide the reference potential of the working electrode 1131, so the detection potential can be effectively controlled. In another embodiment of the invention, the additional electrode can also only comprise the counter electrode 1231, thus forming a two-electrode system. Compared with the three-electrode system, the effective area of the working electrode 1131 and the counter electrode 1231 can be increased on the limited area of the in vivo part Y, thereby extending the service life of the electrode. Moreover, because one electrode is reduced, the processing process is simpler, however, the working electrode 1131 does not have the detection potential of the reference electrode as a reference, and the reliability of the analyte detection information will be reduced. In another embodiment of the invention, there are two working electrodes 1131, one of which is used to detect the response signal of the interferents or background solution in the host body fluid through the electro redox reaction with the analyte to be detected, and the other is the auxiliary electrode.
Continuing to refer to figures 1 and 2, the in vitro part X is paved with PADs, which correspond to the electrode one-by-one and are electrically connected through wires, that is, the working PAD 1111 corresponding to the working electrode 1131 is electrically connected through wire 1121. The counter PAD 1211 corresponding to the counter electrode 1231 is electrically connected through wire 1221. And reference PAD 1311 corresponding to reference electrode 1331, which is electrically connected through wire 1321. Different PADs, wires and electrodes are insulated from each other to prevent electrical signals from interfering.
Because the sensor 11 is the planar structure, there are two opposite sides, obverse side A and reverse side B. The working electrode 1131, counter electrode 1231 and reference electrode 1331 are laid as one electrode-group on the obverse side A of the sensor. On the other hand, another electrode-group is laid on the reverse side B of the sensor. The electrode-group can be a two-electrode system, a three-electrode system or a double working electrode. Preferably, it is consistent with the electrode-group on the obverse side A, comprising working electrode 1132, counter electrode 1232 and reference electrode 1332. Similarly, PADs are also laid on the side B. In this way, when the service life of any electrode on side A terminates or fails in advance, the electrode with the same name on side B can take over and enter the working state, improving the reliability of the parameter data of the detected analyte and extending the service life of the sensor.
Those skilled in the art should understand that there is no restriction on the sequence and position of the PADs, wires and electrodes laid on the side A And side B of the sensor. The PADs, wires and electrodes on the two sides can be symmetrically or asymmetrically arranged. The corresponding PADs, wires and electrodes are laid on the same side or on different sides. Preferably, the corresponding PADs, wires and electrodes are laid on the same side for the convenience of wire routing. For example, the working electrode 1131 on the side A can be replaced with the counter electrode 1231, or the counter electrode 1231 on the side A can be replaced with the reference electrode 1332 on the side B. No matter how the order and position of the PADs, wires and electrodes on the A and side Bs change, just make the PADs, wires and electrodes have a one-to-one correspondence and insulation relationship with each other.
In other embodiments of the invention, although the planar structure sensor only has the side A And side B, it can also increase the number of electrode-groups by increasing the sensor area or reducing the electrode-area, so as to further increase the service life of the sensor. However, too large sensor area may increase the host’s rejection response and cause host discomfort. Too small electrode-area will reduce the sensitivity of electrode and reduce the reliability of detection parameters. Too many electrode-groups will also increase the complexity of the processing process, such as the wiring of the wire will become very dense. Therefore, it is preferred that the number of electrode-groups is two.
In other embodiments of the invention, each electrode-group can also be distributed on the same side of the sensor, such as side A or side B, which is not limited here.
In the embodiment of the invention, the substrate 111 is a material with excellent insulation performance, mainly from inorganic non-metallic ceramics, silica glass, organic polymers, etc. at the same time, considering the application environment of the implanted electrode, the substrate material is also required to have high impermeability and mechanical strength. Preferably, the substrate material is selected from one or more combinations of Teflon, PE, PVC, aBS, PMMA, PC, PI, etc.
Fig. 3 is a sectional view of the electrode. In an embodiment of the invention, the working electrode (auxiliary electrode) , counter electrode and reference electrode comprise at least an electron conduction layer a, an anti-interference layer b, an enzyme layer c, an adjustment layer d and a biocompatible layer e.
Electron conduction layer
The electron conduction layer a adopts a material with good conductivity and hardening inertia. Preferably, the working electrode and counter electrode are selected from one of graphite electrode, glassy carbon electrode, noble metal and other materials, and the reference electrode is selected from one of Ag/AgCl or calomel. Considering the requirements of good ductility and stability of surface structure, noble metal electrodes such as gold electrode, platinum electrode and silver electrode have become better choices. Further preferred, both working electrode and counter electrode are platinum electrodes.
Anti-interference layer
The anti-interference layer b is located between the enzyme layer and the electron conduction layer. Interferents are molecules or substances that will undergo electrochemical reduction or electrochemical oxidation directly or indirectly through electron transfer agents on the electrode surface, thus generating an error signal that interferes with the detection of analytes. For example, for the determination of glucose as the analyte, common interferents in the body comprise urea, ascorbic acid, paracetamol, and so on.
In a preferred example, the anti-interference layer b can prevent one or more interferents from penetrating into the electrolyte around the electrode. For example, the anti-interference layer b will allow the analytes (e.g., hydrogen peroxide) to be measured on the electrode to pass, while at the same time preventing the passage of other substances (e.g., potential interfering substances) . In a preferred scheme, the anti-interference layer b can be a very thin film designed to limit the diffusion of substances with molecular weight greater than 34Da.
In another preferred example, the anti-interference layer b may be an organic polymer, which may be made from organosilane and a hydrophilic copolymer. The hydrophilic copolymers, more preferably poly-ethylene glycol (PEG) , poly-methacrylic acid, 2-hydroxyethyl ester and poly-lysine. In a preferred embodiment, the thickness range of the anti-interference layer b may be 0.1um or less to 10um or more. The more preferred thickness range is 0.5um to 5um.
Enzyme layer
The enzyme layer c is coated with active enzyme, and the corresponding active enzyme is coated according to the type of analyte to be detected. The active enzyme can make the analyte to be detected produce some chemical reactions and generate electrons. According to different concentrations of analyte to be detected, the number of electrons generated is different, and the electrons are collected by the electron conduction layer, thus forming different current intensities. Therefore, the current intensity information can be used to characterize the analyte parameter information.
Preferably, the enzyme layer c is coated with glucose oxidase (Gox) .
Adjustment layer
The adjustment layer d is located above the enzyme layer. In the embodiment of the invention, when glucose oxidase is coated on the enzyme layer, the regulating layer d is mainly used to regulate the transmittance of oxygen and glucose transmitted to the enzyme layer. The glucose content (molar concentration) in body fluid is one order of magnitude higher than that of oxygen. However, for enzyme-based sensor that require oxygen participation, excess oxygen needs to be supplied to ensure that oxygen does not become a limiting substance, so that the sensor can respond linearly to changes in glucose concentration without being affected by oxygen partial pressure. In other words, when oxygen content becomes a limiting factor, the linear range of glucose oxygen monitoring reaction cannot reach the expected concentration range. When there is no semi permeable membrane on the enzyme layer to regulate the permeation of oxygen and glucose, the upper limit of the linear response of the sensor to glucose can only reach about 40mg/dL. However, in clinical situations, the upper limit of linear response of blood glucose level needs to reach about 500mg/dL.
The regulating layer d mainly functions as a semipermeable membrane to regulate the amount of oxygen and glucose transmitted to the enzyme layer. More specifically, excess oxygen becomes a non-restrictive factor. The upper limit of the linear response to glucose of the sensor with an adjustment layer can reach a higher level than that without an adjustment layer. In a preferred example, the ratio of oxygen glucose transmittance of the regulating layer d can reach 200: 1, which can ensure that there is enough oxygen for the enzymatic reaction for various glucose and oxygen concentrations that may occur under the skin.
In a preferred example, the adjustment layer d may be an organic polymer, which may be manufactured from organosilane and a hydrophilic copolymer. Hydrophilic copolymers, more preferably copolymerized or grafted poly-ethylene glycol (PEG) . Other hydrophilic copolymers that may be used comprise but are not limited to other diols, such as propylene glycol, esters, amides, carbonates, and polypropylene glycol. The use of silicone polymers can significantly improve oxygen transport and effectively control glucose permeation. In the preferred embodiment, the thickness range of the adjustment layer d can be 1um or less to 50um or more, and the more preferred thickness range is 1um to 10um.
Biocompatible layer
The biocompatible layer e is located at the outermost part of the electrode, aiming to eliminate the body’s rejection of foreign bodies and reduce the formation of a shielding cell layer around the implanted electrode.
In a preferred example, the biocompatible layer e can be manufactured from organosilane and a hydrophilic copolymer. Hydrophilic copolymers, more preferably copolymerized or grafted poly-ethylene glycol (PEG) . Other hydrophilic copolymers that may be used, comprising but not limited: diols, such as propylene glycol, esters, amides, carbonates, and polypropylene glycol.
In a preferred embodiment, the thickness range of the biocompatible layer e may be 1um or less to 100um or more. The more preferred thickness range is 10um to 30um.
In the embodiment of the invention, the thickness of the substrate 11 is 0.01～0.8mm, the electrodes are rectangular, the width of each electrode is 0.01～1mm, and the area is 0.1～2mm2.
In other embodiments of the invention, the surface of each electrode is also provided with a carbon nanotube layer modification layer. Taking advantage of the unique mechanical strength, high specific obverse side Area, rapid electron transfer effect and chemical stability of carbon nanotubes, carbon nanotubes are modified to the electrode surface by physical adsorption, embedding or covalent bonding on the formed electrode surface to improve the electron transfer speed. At the same time, due to its large specific obverse side Area, carbon nanotubes can be used as an excellent catalyst (enzyme) carrier. The carbon nanotube layer modified layer can be fixed on the electrode surface by Nafion solution dispersion method, covalent fixation method, etc.
Fig. 4 is the schematic diagram of the function realization of the embodiment of the invention.
After the sensor penetrates the host, the in vivo circuit applies voltage to the PAD, and the electrode corresponding to the PAD is activated to enter the working state. Generally speaking, the effective working time of the electrode after being activated is 1-14 days. After 14 days, the enzyme activity on the electrode decreases and enters the failure state. At the same time, there may be reasons such as electrode damage or processing errors, and the activated electrode will enter the failure state in advance. If a single group of electrodes is set on the sensor, once a certain electrode enters the failure state, the sensor will fail, and the user needs to replace the sensor, which reduces the user experience and increases the user’s use cost. If multiple groups of electrodes are set on the sensor, such as two groups of electrodes, once one electrode enters the failure state, the in vivo circuit will apply voltage to the PAD corresponding to the electrode with the same name of other electrode-groups, activate the electrode with the same name, make it enter the working state, replace the failed electrode, and make the sensor continue to work normally.
For details, refer to Fig. 1 and Fig. 2. After the sensor penetrates the host, the working PAD 1111, the counter PAD 1211 and the reference PAD 1311 on side A are preferentially applied with voltage by the in vivo circuit. The working electrode 1131, the counter electrode 1231 and the reference electrode 1331 on side A enter the working state. Once any one of the working electrode 1131, the counter electrode 1231 and the reference electrode 1331 fails in advance or ends its life, the in vivo circuit switches the PAD object to which the voltage is applied, For example, when the working electrode 1131 fails in advance, the in vivo circuit switches to apply voltage to the fourth PAD 1112 on the side B, activates the working electrode 1132 on the side B, and combines it with the counter electrode 1231 and the reference electrode 1331 that have not yet failed to form a new electrode-group to detect the analyte to be tested, thus avoiding the early failure of the sensor 11. The user does not need to replace the sensor because of the early failure of the working electrode 1131, which enhances the user experience, it also reduces the cost of replacing sensors.
Those skilled in the art should understand that the above embodiment is not limited to the failure of the working electrode, other electrodes such as the counter electrode and the reference electrode fail, or two or three electrodes fail at the same time. The method of using the same name electrode to replace the failed electrode in the above embodiment can be adopted.
In addition, it can also be switched before the electrode fails or the service life ends, and the preset condition at this time is the preset time t. For example, the electrode fails after 14 days in the normal working state, and the preset time t is 2 days. When the first electrode-group is energized and activated, after working for 2 days, switch to the second electrode-group, the second electrode-group is activated, and the first electrode-group is no longer energized and enters the sleep state. After the second electrode-group works for 2 days, other electrode-groups can be activated or the first electrode-group can be activated again. This cycle is activated until the service life of all electrode-groups ends and all electrode-groups enter the failure state. In this mode, the service life of multiple electrode-groups is superimposed, thus extending the service life of the sensor.
Those skilled in the art should understand that the preset time t can be any day within 14 days. If the service life of the electrode is extended to n (n>14) days due to process improvement or other reasons, the preset time t can be any day within n days.
Implementation example 2
Step structure sensor
Fig. 5 is a top view of the sensor with a stepped structure in the embodiment of the invention. Fig. 6 is side A view of the step structure of the sensor in the embodiment of Fig. 5.
The sensor 21 of the step structure comprises side A and side B, and each side is divided into the in vitro part X and the in vivo part Y with the dotted line as the dividing line. The in vivo part Y comprises a first substrate 211, a second substrate 221 and a third substrate 231, forming a step structure with each other. The number and layers of the substrate are consistent with the number of electrodes on the surface. For example, when there is a three-electrode system on the substrate, the substrate is a three-layer step structure. When the side A is a two-electrode system, the substrate is a two-layer step structure.
In the embodiment of the invention, different layers of substrates are insulated from each other, and each electrode is electrically connected with the corresponding PAD through the wires distributed on one substrate (such as the third substrate) , that is, a part of the wire is in contact with the electrode, and the main part of the wire is located under the substrate, which can effectively protect the wire. At the same time, the electrodes are distributed on different layers of substrates. On the one hand, the spacing of electrodes is enlarged, which reduces the influence of the microenvironment on the electrode surface. At the same time, the electrode distribution of the step structure can effectively inhibit the interference of human response on the electrode response. On the other hand, if the electrodes are distributed on different planes, the width of the whole sensor can be further reduced on the premise that the effective area of each electrode is unchanged. The width of step structure sensor can be reduced by about half on the basis of plane structure sensor.
Correspondingly, side B and side A are symmetrical step structures. The in vitro part X is paved with PADs, which correspond to the electrode one-by-one and are electrically connected through the wire, that is, the working PAD 2111 corresponding to the working electrode 2131 is electrically connected through the wire 2121. The counter PAD 2211 corresponding to the counter electrode 2231 is electrically connected through wire 2221. And the reference PAD 2311 corresponding to the reference electrode 2331, which is electrically connected through wire 2321. Different PADs, wires and electrodes are insulated from each other to prevent electrical signals from interfering.
The working electrode 2131, counter electrode 2231 and reference electrode 2331 are laid as an electrode-group on the obverse side A of the sensor. On the other hand, another electrode-group is laid on the reverse side B of the sensor. The electrode-group can be a two-electrode system, a three-electrode system or a double working electrode. Preferably, it is consistent with the electrode-group on the obverse side A, comprising the working electrode 2132, counter electrode 2232 and reference electrode 2332. Similarly, PADs are also laid on the side B. The PADs correspond to the electrodes on the side B one-by-one and are electrically connected through wires, that is, the fourth PAD 2112 corresponding to the working electrode 2132 is electrically connected through wires 2122. The fifth PAD 2212 corresponding to the counter electrode 2232 is electrically connected through wire 2222. And the sixth PAD 2312 corresponding to the reference electrode 2332, which is electrically connected through wire 2322. In this way, when the service life of any electrode on side A terminates or fails in advance, the electrode with the same name on side B can take over to enter the working state, improve the reliability of the parameter data of the detected analyte, and extend the service life of the sensor.
Those skilled in the art should understand that there is no restriction on the sequence and position of the PADs, wires and electrodes laid on the side A And side B of the sensor. The PADs, wires and electrodes on the two sides can be symmetrically or asymmetrically arranged. The corresponding PADs, wires and electrodes are laid on the same side or on different sides. Preferably, the corresponding PADs, wires and electrodes are laid on the same side for the convenience of wire routing. For example, the working electrode 2131 on the side A can be replaced with the counter electrode 2231, or the counter electrode 2231 on the side A can be replaced with the reference electrode 2332 on the side B. No matter how the order and position of the PADs, wires and electrodes on the side A And side B change, just make the PADs, wires and electrodes have a one-to-one correspondence and insulation relationship with each other.
In other embodiments of the invention, although the step structure sensor only has the opposite side A and side B, it can also increase the number of electrode-groups by increasing the sensor area or reducing the electrode-area, so as to further increase the service life of the sensor. However, too large sensor area may increase the host’s rejection response and cause host discomfort. Too small electrode-area will reduce the sensitivity of electrode and reduce the reliability of detection parameters. Too many electrode-groups will also increase the complexity of the processing process, such as the wiring of the wire will become very dense. Therefore, it is preferred that the number of electrode-groups is two.
In other embodiments of the invention, each electrode-group can also be distributed on the same side of the sensor, such as side A or side B, which is not limited here.
In the embodiment of the invention, the first substrate 211, the second substrate 221 and the third substrate 231 are materials with excellent insulation properties, mainly from inorganic non-metallic ceramics, silica glass and organic polymers. At the same time, considering the application environment of the implanted electrode, the substrate material is also required to have high water permeability and mechanical strength. Preferably, the material of the substrate is selected from one or more combinations of poly-tetrafluoroethylene (Teflon) , poly-ethylene (PE) , poly-vinyl chloride (PVC) , acrylonitrile butadiene styrene copolymer (ABS) , poly-methyl methacrylate (PMMA) , poly-carbonate (PC) , poly-imide (PI) , etc.
In an embodiment of the invention, the working electrode (auxiliary electrode) , counter electrode and reference electrode at least comprise an electron conduction layer a’, an anti-interference layer b’, an enzyme layer c’, an adjustment layer d’ and a biocompatible layer e’, the properties of each layer and their related descriptions can be seen in embodiment 1, and will not be repeated here.
Implementation example 3
Cylindrical structure sensor
Fig. 7 is a schematic diagram of the cylindrical structure of the sensor in the embodiment of the invention. Fig. 8 is the V-V’ sectional view of the cylindrical structure of the sensor in the embodiment of Fig. 7.
The columnar sensor 31 is divided by the dotted line on the figure, and its substrate 311 is divided into the in vitro part X and the in vivo part Y. The in vitro part X is planar or cylindrical, preferably planar. The in vivo part Y comprises the substrate 311, which is cylindrical, and each electrode is surrounded on the surface of the substrate. Compared with the planar electrode, the electrode with ring structure does not have sharp edges, which reduces the irritation to human tissues and human rejection reaction, which is conducive to achieving implantable long-term detection and improving the service life of the sensor.
The in vivo part Y comprises at least one working electrode 3131 and at least one additional electrode. Obviously, in this embodiment, the additional electrode comprises a counter electrode 3231 and a reference electrode 3331, thereby forming a three-electrode system. The counter electrode 3231 is the other electrode relative to the working electrode 3131, forming a closed loop with the working electrode 3131, so that the current on the electrode can be normally conducted. The reference electrode 3331 is used to provide the reference potential of the working electrode 3131, therefore, the detection potential can be effectively controlled. In another embodiment of the invention, the additional electrode can also only comprise the counter electrode 3231, thus forming a two-electrode system. Compared with the three-electrode system, the effective area of the working electrode 3131 and the counter electrode 3231 can be increased on the limited area of the in vivo part Y, thereby extending the service life of the electrode. Moreover, because there is less one electrode, the processing process is simpler, however, the working electrode 3131 does not have the detection potential of the reference electrode as a reference, and the reliability of the analyte detection information will be reduced. In another embodiment of the invention, there are two working electrodes 3131, one of which is used to detect the response signal of the interferents or background solution in the host body fluid by electro redox reaction with the analyte to be detected, and the other electrode is the auxiliary electrode.
Continuing to refer to Fig. 7, the in vitro part X is paved with PADs, which correspond to the electrode one-by-one and are electrically connected through wires, that is, the working PAD 3111 corresponding to the working electrode 3131 is electrically connected through wire 3121. The counter PAD 3211 corresponding to the counter electrode 3231 is electrically connected through wire 3221. And the reference PAD 3311 corresponding to the reference electrode 3331 are electrically connected through the wire 3321. The working electrode 3131, the counter electrode 3231 and the reference electrode 3331 form an electrode-group. Different PADs, wires and electrodes are insulated from each other to prevent electrical signals from being disturbed.
Each electrode is laid on the in vivo part Y in a semi surrounded manner, so there can be two electrodes at the same place to form an enclosure for the in vivo part Y. Specifically, with reference to Fig. 8, at the V-V’ of the in vivo part Y, the reference electrodes 3331 and 3332 are semicircular rings, respectively, whose inner diameter is equal to the outer diameter of the in vivo part Y, and are in insulated contact with each other, maximizing the obverse side Area of the in vivo part Y.
In other embodiments of the invention, the working electrode 3131 or counter electrode 3231 of the same electrode-group, or the working electrode (not shown in the figure) or counter electrode (not shown in the figure) of other electrode-groups can form an enclosure with the reference electrode 3331, so that in the case of termination or early failure of any electrode, its corresponding electrode of the same name can take over and enter the working state, improve the reliability of the parameter data of the detected analytes and extend the service life of the sensor.
Those skilled in the art should understand that the sequence and position of the PADs, wires and electrodes laid on the substrate 311 are not limited. The PADs, wires and electrodes can be symmetrically or asymmetrically arranged. No matter how the order and position of the PADs, wires and electrodes change, it is only necessary to make the PADs, wires and electrodes have a one-to-one correspondence and insulation relationship with each other.
In other embodiments of the invention, the number of electrode-groups can also be increased by increasing the sensor area or reducing the electrode-area, thereby further increasing the service life of the sensor. However, too large sensor area may increase the host’s rejection response and cause host discomfort. Too small electrode-area will reduce the sensitivity of electrode and reduce the reliability of detection parameters. Too many electrode-groups will also increase the complexity of the processing process, such as the wiring of the wire will become very dense. Therefore, it is preferred that the number of electrode-groups is two.
In the embodiment of the invention, the substrate 311 is a material with excellent insulation performance, mainly from inorganic non-metallic ceramics, silica glass, organic polymers, etc. at the same time, considering the application environment of the implanted electrode, the substrate material is also required to have high impermeability and mechanical strength. Preferably, the material of the substrate is selected from one or more combinations of poly-tetrafluoroethylene (Teflon) , poly-ethylene (PE) , poly-vinyl chloride (PVC) , acrylonitrile butadiene styrene copolymer (ABS) , poly-methyl methacrylate (PMMA) , poly-carbonate (PC) , poly-imide (PI) , etc.
In the embodiment of the invention, the outer diameter of the in vivo part Y of the substrate 311 and the inner diameter of the electrode are 0.01～100um, preferably 10～50um. The electrode can be a half ring, a 1/3 ring, a 1/4 ring or other proportion of the ring.
In an embodiment of the invention, the working electrode (auxiliary electrode) , counter electrode and reference electrode at least comprise an electron conduction layer a”, an anti-interference layer b”, an enzyme layer c”, an adjustment layer d”, and a biocompatible layer e”, the properties of each layer and their related descriptions can be seen in embodiment 1, and will not be repeated here.
Those skilled in the art can understand that the in vivo part Y of the sensor is not necessarily limited to the shape of the above three embodiments. For example, in other embodiments, it can be circular, semi-circular, conical, spiral and other shapes, and the shape of the electrode arranged on it also changes based on the shape of the in vivo part Y. As long as the electrode can be easily laid on the in vivo part Y, there is no limitation here.
Fig. 9 is a schematic diagram of a continuous analyte detection device 100 according to an embodiment of the invention. The continuous analyte detection device 100 comprises a bottom shell 101 for mounting on the surface of the host skin. The sensor unit 102 comprises a substrate 1021 and a micro analyte sensor 11 (21/31) as previously described. The micro analyte sensor 11 (21/31) is fixed on the substrate, and the sensor unit 102 is installed on the bottom shell 101 through the substrate. The transmitter unit 103 comprises an in vivo circuit 1031, a transmitter 1032, and an electrical connection area 1033. The electrical connection area 1033 is electrically connected with the sensor unit 102. The in vivo circuit 1031 stores the predetermined conditions for switching electrodes described above. The transmitter 1032 is used to send analyte parameter information to the outside world. The battery 104 is used to provide electric energy. The receiver 105, which is used to receive analyte parameter information and indicate to the user.
Fig. 10a to Fig. 10o are the schematic diagrams of different schemes of the sensor in the embodiment of the invention.
Referring to Fig. 10a, in order to easily and clearly show the structural characteristics of the sensor 41, the length, width, thickness and curve characteristics of the sensor are expressed in exaggerated form in Fig. 10a. The actual length, width, thickness and curve characteristics of the sensor may be different from those shown in the figure.
In other illustrations in this invention, the length, width, thickness and curve characteristics of the sensor are expressed in the same exaggerated form. The actual length, width, thickness and curve characteristics of the sensor may be different from those in the illustration, and will not be repeated below.
Similarly, the wires, PADs and electrodes described earlier and later are also expressed in the figure in exaggerated form. The wires, PADs and electrodes in the Fig. are only used as auxiliary examples to express the scheme of the invention, and are not completely equivalent to the wires, PADs and conductors in the actual sensor. For example, the wire in the actual sensor is a flat wire with a certain width, which is shown in the form of lines in the illustration.
In some embodiments of the invention, the substrate 411 of the sensor 41 is generally a flexible material, such as one or more combinations selected from poly-tetrafluoroethylene, poly-ethylene, poly-vinyl chloride, acrylonitrile butadiene styrene copolymer, poly-methyl-methacrylate, poly-carbonate, poly-imide, which has good electrical insulation characteristics, and the electrode and electrode, wire and wire set on it can be insulated from each other. In the preferred embodiment of the invention, the substrate 411 is made of poly-imide, which has good adaptability to human physiology and will not suffer from excessive rejection due to penetration into the subcutaneous skin.
In some embodiments of the invention, after the sensor 41 is penetrated into the subcutaneous skin, the substrate 411 is generally soft in order to adapt to the repeated peristalsis of the muscle, and the soft substrate is repeatedly bent during the repeated peristalsis of the muscle. The substrate 411 is easy to reach the extreme fatigue early (not reaching the design service life of the sensor 41, such as 14 days) , resulting in damage or even fracture, which will make the electrode set on the substrate 411 The wire is exposed and short circuited, or directly broken and damaged, affecting the detection reliability of sensor 41. In order to improve the detection reliability of the sensor 41, the mechanical strength of the substrate 411 needs to be strengthened to extend the time for the substrate 411 to reach the limit fatigue and meet the design service life of the sensor 41.
In some embodiments of the invention, insulating materials used to strengthen the mechanical strength of the substrate 411 can be post manufactured some areas of the substrate 411. Here, "post manufacture" refers to that after the sensor 41 is manufactured, that is, electrodes, PADs and wires are set on the substrate to form a complete sensor 41, and then at least one layer of insulating material is set on the substrate 411. Obviously, with the addition of insulating materials, the mechanical strength of the substrate 411 in the corresponding area will be improved, and the time to reach the ultimate stress fatigue will also be extended.
In some embodiments of the invention, the number of layers of insulating material behind the substrate 411 can be multiple layers, such as 2, 3 or more layers, which can further increase the mechanical strength of the substrate 411, but the setting of multiple layers of insulating material will cause the substrate in the corresponding area to become soft, and the user’s discomfort will be increased after being penetrated subcutaneously. Similarly, the thicker the insulating material is set, the mechanical strength of the substrate 411 can also be increased, but too thick insulating material will also cause the substrate in the corresponding area to become soft, which will increase the user’s discomfort after being stabbed under the skin. Therefore, it is necessary to control the number and thickness of insulating materials.
In the preferred embodiment of the invention, the number of layers of insulating material is 1-10, and the thickness of each layer is 0.1um-200um.
In the preferred embodiment of the invention, the number of layers of insulating material is 1, and its thickness is 25um. During the processing of sensor 41, setting multiple layers of insulating material will increase the complexity of the processing process. Therefore, 1 layer of insulating material can not only enhance the mechanical strength of substrate 411, but also will not lead to too complex processing process. Setting its thickness to 25um can maintain sufficient softness of substrate 411, it will not increase the user’s discomfort after the substrate penetrates into the user’s subcutaneous skin.
In some embodiments of the invention, the insulating material can be one or more combinations of poly-tetrafluoroethylene, poly-ethylene, poly-vinyl chloride, acrylonitrile butadiene styrene copolymer, poly-methyl-methacrylate, poly-carbonate and poly-imide. The characteristics of the above materials have been described previously and will not be repeated here. Preferably, the material of the insulating material is poly-imide, which is consistent with the material of the substrate 411 and has the same physical properties. When the extension, contraction, bending and other actions occur, the insulating material of the same material and the substrate 411 have the same extension, contraction or bending scale, which will not cause the insulating material to wrinkle or fall off due to the stress concentration on the substrate 411 due to the different scale.
In some embodiments of the invention, the insulating material can be set on the substrate 411 by coating. When the insulating material is poly-imide, the poly-imide can be heated to liquid state first, and then coated on the substrate 411.
In other embodiments of the invention, the insulating material can be set on the substrate 411 by pasting. When the insulating material is poly-imide, the poly-imide precursor can be used as the pasting material. After the poly-imide precursor is cured, its physical properties are consistent with the poly-imide substrate, and it is consistent in extension, contraction and bending, the insulation material will not bulge, fold or fall off on the substrate 411 due to stress concentration or uneven stress, which improves the yield of the sensor.
In the above process of setting the insulating material on the substrate 411 by coating or pasting, it is necessary to ensure that the electrodes, PADs and wires on the substrate 411 have established a good electrical connection, and there is good insulation between electrodes, PADs and PADs, wires and wires, so as to effectively realize the sensor function.
In some embodiments of the invention, when the insulating material is set on the substrate 411, the central conductive area of the PAD and electrode should be avoided, otherwise the function of the sensor 41 will not be realized.
In some embodiments of the invention, the area where the insulating material is set after comprises at least one of the reverse area 412 of the PAD-area a or the reverse area 413 of the electrode-area b. preferably, both the PAD-reverse-area 412 and the electrode reverse area 413 are provided with insulating materials.
In other embodiments of the invention, the area where the insulating material is post manufactured can also comprise the area near the electrodes and PADs, avoiding the central conductive area of the electrodes and PADs. In this case, the insulating material can cover the edge of the electrode and PAD, increase the adhesion degree of the electrode and PAD with the substrate, prevent the edge of the electrode and PAD from warping, and further prevent the electrode and PAD from being damaged or even falling off.
In some embodiments of the invention, the PAD-reverse-area 412 and the electrode reverse area 413 can be two independent areas as shown in Fig. 10a. In other embodiments of the invention, the PAD-reverse-area 412 and the electrode reverse area 413 can also be connected into a coherent area.
In other embodiments of the invention, the sensor 41 may be installed in the analyte detection device in the form of bending, that is, the in vitro part X is bent relative to the in vivo part Y, or the in vivo part Y is bent relative to the in vitro part X. Since the in vitro part X is fixed in the analyte detection device, and the in vivo part Y penetrates into the subcutaneous layer and moves with the user’s muscle peristalsis, the in vivo part Y is also frequently bent relative to the in vitro part X. It is also necessary to set insulating materials after the bending-obverse-area 414 of the in vivo part Y relative to the in vitro part X bending-area c. Setting insulating materials after bending the obverse area 414 can not only increase the mechanical strength of the substrate of the corresponding area, but also cover the conductors in the corresponding area and provide additional insulation and protection for the conductors.
In some embodiments of the invention, the sensor 41 adopts a three-electrode system, comprising a working electrode 4141, a counter electrode 4241 and a reference electrode 4341, and their corresponding working PAD 4111, a counter PAD and a reference PAD 4311, as well as the wires 4121/4221/4321 connecting each PAD and electrode. In other embodiments of the invention, the sensor 41 can also adopt a two-electrode system, which does not comprise the reference electrode 4341 and the corresponding PADs and wires. This is a common general knowledge in the art and will not be described here.
In some embodiments of the invention, the wires 4121/4221/4321 can be set on the surface or inner of the substrate 411 through etching, laser welding and other processes. When the wires 4121/4221/4321 are arranged on the inner of the substrate 411 and are electrically connected with the PADs or electrodes arranged on the surface of the substrate 411, holes 4141/4241/4341 are opened at the corresponding positions of the electrical connection on the substrate 411, and the electrical connection ends of the wires 4121/4221/4321 are led out to the surface of the substrate 411 through holes 4141/4241/4341 to establish electrical connections with the electrodes 4131/4231/4331 respectively. Similarly, the other end of wire 4121/4221/4321 is electrically connected with PAD 4111/4211/4311 through a hole (not shown in the figure) . When conductors 4121/4221/4321 are set in the inner layer of substrate 411, substrate 411 can provide insulation protection for each conductor to avoid signal loss or instability caused by short circuit between conductors, but the processing technology is relatively complex.
In some embodiments of the invention, the substrate 411 is a single-layer side as shown in Fig. 10a.
In other embodiments of the invention, the substrate 411 may also be a multilayer side as shown in Fig. 10b. The substrate 411 can be composed of multiple layers of secondary-substrates, such as the first substrate 411d, the second substrate 411e, and/or the third substrate 411f. At least one electrode and at least one wire can be arranged on each layer of substrate 411d/411e/411f. The electrodes 4131/4231/4331 are respectively set on the secondary-substrates 411d/411e/411f of different layers. On the one hand, it can increase the distance between electrodes, reduce the signal interference between electrodes, and improve the detection reliability. On the second hand, the electrode on the secondary-substrate of each layer can be set with a larger area. The electrode with a larger area has more sufficient contact with body fluid, the signal is more stable, and the detection reliability can be improved. On the third hand, since the electrode is set on the secondary-substrate of different layers, the wires 4121/4221/4321 electrically connected with the electrode can also be routed on different secondary-substrates, so the secondary-substrate can also electrically insulate the wires 4121/4221/4321. Based on this, the wires 4121/4221/4321 can be routed on the surface of the substrates 411d/411e/411f at all levels, simplifying the wire processing technology. On the fourth hand, although the conductors 4121/4221/4321 can be laid on the surface of the secondary-substrate 411d/411e/411f of different layers, once the substrate of a certain layer is damaged, the conductors of the adjacent two layers may contact and short circuit. Therefore, when laying the conductors 4121/4221/4321 on the secondary-substrate 411d/411e/411f, the conductors 4121/4221/4321 can be staggered as shown in the top view of Fig. 10b to form a stepped distribution of conductors, even if the substrate of a certain layer is damaged, the conductors of two adjacent layers will not be short circuited due to contact, which improves the detection reliability. On the fifth hand, compared with the single-layer substrate, the substrate composed of multi-layer substrate has higher mechanical strength, is not easy to be broken or damaged, and extends and improves the detection reliability.
The setting of each electrode on the secondary-substrate is not fixed. In some embodiments of the invention, as shown in Fig. 10b, the reference electrode 4331 can be set on the secondary-substrate 411f of the top layer. The cost of the reference electrode 4331 is higher than that of the working electrode 4131 and the counter electrode 4231. The reference electrode 4331 on the secondary-substrate 411f of the top layer is manufactured in the final process, which can protect the reference electrode 4331 from damage. In other embodiments of the invention, the reference electrode 4331 can also be set on the secondary-substrate 411d of the bottom layer. The reference electrode 4331 is thicker than the working electrode and the counter electrode 4231, and is located on the secondary-substrate 411d of the bottom layer, which can improve the thickness consistency of the sensor 41 without making the sensor 41 have too large thickness difference, which is convenient for the storage and use of the sensor 41. In Fig. 10b, the thicknesses of the secondary-substrates 411d/411e/411f and electrodes 4131/4231/4331 of each layer are expressed in exaggerated form. It is understandable that this does not affect the description of this scheme.
In some embodiments of the invention, the secondary-substrates 411d/411e/411f of each layer can be manufactured layer by layer, that is, after the bottom layer substrate 411d is manufactured, the middle layer substrate 411e is manufactured on the basis of the bottom layer substrate 411d. Similarly, after the middle layer substrate 411e is manufactured, the top layer substrate 411f is manufactured. In the normal manufacture process, the substrate materials, such as poly-imide, are coated on the mold layer by layer after heating to form a complete secondary-substrate after curing. However, during the curing process, there may be insufficient curing of the materials in some areas, or the curing degree of the substrate materials on different secondary-substrates is inconsistent, or the curing degree of the substrate materials on different secondary-substrates is inconsistent, the substrate will be brittle during subsequent use, which will cause the electrodes, wires and PADs on the substrate to be short circuited to each other or even damaged, affecting the detection reliability of the sensor.
Referring to Fig. 10c, based on the existing problem that brittle fracture failure may occur in the substrate, in other embodiments of the invention, the secondary-substrates 411d/411e/411f of each layer can be prefabricated first. Here, the prefabrication completion refers to that after the substrate material of each layer of substrates 411d/411e/411f is fully cured, the electrodes, wires or PADs are manufactured on the substrate. According to the design requirements of sensor 41, the electrodes, wires or PADs set on the secondary-substrate of each layer The wires or PADs may or may not be the same. After prefabrication, the secondary-substrates 411d/411e/411f of each layer are combined into a whole by pasting. For example, when the secondary-substrate 411d/411e/411f material is selected as poly-imide, the precursor of poly-imide can be used to paste the substrates 411d/411e/411f of each layer, and finally a complete substrate of sensor can be obtained. Since the substrates 411d/411e/411f of each layer are pasted as a whole after being fully cured, it can not only avoid the embrittlement problem caused by insufficient curing of materials in the substrate of the same layer, but also avoid the embrittlement problem caused by insufficient curing of materials between secondary-substrate of different layers, which improves the detection reliability of the sensor. In addition, since the substrates 411d/411e/411f of each layer can be prefabricated independently and then assembled into a whole, the manufacturing efficiency of the sensor 41 can also be increased in the manufacturing process.
It is worth pointing out that in some embodiments of the invention, on the secondary-substrate 411f of the top layer, the PADs 4111/4211/4311 corresponding to each electrode 4131/4231/4331 also need to be prefabricated to make the function of the sensor 41 complete. After the secondary-substrate 411d/411e/411f of each layer is pasted, the wires on the secondary-substrate 411d/411e are led to the secondary-substrate 411f of the top layer by drilling to establish an electrical connection with the PADs on the secondary-substrate 411f.
In some embodiments of the invention, the thickness of each layer of substrate 411d/411e/411f can be 0.1～200um. Compared with the single-layer substrate scheme shown in Fig. 10a, the thickness of each layer of substrate 411d/411e/411f is a little thinner. Otherwise, the superposition of several layers of substrate will make the overall thickness too thick, not enough softness, and will increase the user’s discomfort when stabbing into the user’s subcutaneous. Therefore, it is preferred that the thickness of each layer of substrate 411d/411e/411f is 0.1～200um. Further preferred, the thickness of each layer of substrate 411d/411e/411f is about 10um, and the thickness of the whole is about 25～35um. This thickness will not be easily damaged or broken because it is too thin, nor will it increase the discomfort of users because it is too thick. Those skilled in the art can understand that the actual thickness of the secondary-substrate 411d/411e/411f of each layer may deviate due to the error of the processing technology.
In some embodiments of the invention, the material of the substrates 411d/411e/411f at all levels is preferably poly-imide. In order to paste the substrates 411d/411e/411f at all levels into a whole, the bonding material can preferably be poly-imide precursor. After curing, the poly-imide precursor and poly-imide can maintain the consistency of physical properties. Such a bonding method can prevent the substrates 411d/411e/411f at all levels from peeling off or even falling off due to stress concentration or uneven stress.
In some embodiments of the invention, after the substrates 411d/411e/411f of each layer are combined to form a whole, insulating materials can still be set on the surface of the substrate to further strengthen its mechanical strength. Referring to Fig. 10a and Fig. 10b, similarly, the areas where insulating materials can be set comprise the PAD-reverse-area 412 of PAD-area a, the electrode reverse area 413 of electrode-area b, and the bending-obverse-area of bending-area c. In other embodiments of the invention, the insulating material located in the reverse area 412 of the PAD and the reverse area 413 of the electrode in the electrode-area b can be connected into a piece to form a coherent area. In the embodiment of the invention, the thickness and the number of layers of the insulating material are the same as those previously described, and will not be repeated here.
Referring to Fig. 10d, in some embodiments of the invention, at least one electrode may be set on the reverse side B of the substrate 411. In this case, an electrode obverse area 415 will be left on the obverse side A of the substrate 411. Insulating materials can also be set on this area to improve the mechanical strength of the electrode obverse area 415. Correspondingly, the electrode arranged on the reverse side B of the substrate 411 will occupy an area, and the insulating material needs to avoid this area to form the reverse area 413 of the electrode as shown in Fig. 10d. The area 413 on the reverse area of the electrode may be the area disconnected from the middle. This area is provided with electrodes or may be a continuous area. The electrodes are set on the side of this area (not shown in the figure) . The continuous insulating material can reduce the manufacturing process steps.
In some embodiments of the invention, the electrode arranged on the reverse side of the substrate 411 may be a counter electrode 4231. Setting the counter electrode 4231 on the opposite side of the substrate 411, on the one hand, can increase the relative distance between the counter electrode 4231 and the working electrode 4131, reduce the current crosstalk between the counter electrode 4231 and the working electrode 4131, and reduce the noise. On the other hand, the area of the counter electrode 4231 can be maximized, so as to reduce the electrochemical polarization and improve the accuracy and sensitivity of the detection signal.
In other embodiments of the invention, the electrode arranged on the reverse side of the substrate 411 may be a reference electrode 4331. The reference electrode 4331 is set on the opposite side of the substrate 411. On the one hand, during the manufacturing process, the reference electrode 4331 can be manufactured separately, which will not affect the working electrode 4131 and the counter electrode 4231, improving the yield of finished products. On the other hand, it can reduce the circuit risk caused by the migration of ag/cl substance of reference electrode 4331 and improve the detection reliability.
In other embodiments of the invention, the electrode arranged on the reverse side of the substrate 411 may be the working electrode 4131. The working electrode 4131 is set on the opposite side of the substrate 411. If the counter electrode 4231 and the reference electrode 4331 are short circuited, the three-electrode system will become a two-electrode system, which will not affect the detection current, and the detection signal will not change suddenly, improving the detection stability.
Referring to Fig. 10e, in some embodiments of the invention, because the electrodes are respectively set on the obverse side and reverse side of the substrate 411, the obverse side and reverse side of the substrate 411 need to be manufactured to set electrodes, wires, etc., which will inevitably cause damage to the other side in the processing process. Based on this, the obverse side and reverse side of the substrate 411 can be manufactured separately, that is, the obverse side A and reverse side B of the substrate 411 are manufactured respectively, and then the obverse side A and reverse side B are assembled into a whole, forming a complete sensor can improve the integrity of the double-sided substrate.
In some embodiments of the invention, electrodes, wires and PADs are manufactured on the substrate 411a of obverse side A, while electrodes and wires are manufactured on the reverse side B of the substrate 411b. The setting positions of the above electrodes, wires and PADs on the substrate 411a and substrate 411b are not limited. In order to strengthen the mechanical strength of substrate 411a and substrate 411b, after processing the electrode, wire and PAD, another layer of insulating material can be manufactured. The setting position of insulating material can refer to the above description, avoiding the PAD-area and electrode-area.
In some embodiments of the invention, the substrate 411a and the substrate 411b can be combined into a whole by pasting. For example, the materials of the substrate 411a and the substrate 411b are poly-imide, and the substrate 411a and the substrate 411b are pasted together using the precursor material of poly-imide. Refer to Fig. 10c and its description for relevant technical details.
Although the mechanical strength of the substrate 411 can be enhanced by setting insulating materials on the substrate 411 to reduce the possibility of electrode damage, in actual use, with the increase of user movement and other reasons, the substrate 411 may be bent repeatedly or the degree and times of bending may exceed the expectation, and the electrode may still be damaged. Therefore, some necessary measures can be taken to prevent the electrode from being damaged.
Referring to Fig. 10f, in some embodiments of the invention, changing the whole electrode into an electrode unit array composed of smaller electrode units can prevent the whole electrode from being damaged and improve the detection reliability of the sensor. For example, the original working electrode 4131 is cut into smaller working electrode units 4131a, and then the working electrode units 4131a are assembled into an array to form a working electrode array. Each unit in the working electrode array jointly realizes the detection function of the working electrode 4131, and its function is almost the same as that of the original working electrode 4131. All working electrode units 4131a are laid on wire 4121, and the current of each working electrode unit 4131a during the detection of analytes is transmitted through wire 4121. After the whole electrode is made into an electrode unit array, even if the substrate 411 is repeatedly bent with the user’s muscle, the array composed of electrode units can be bent to a certain extent, without breaking and losing the detection performance, which improves the detection reliability. In Fig. 10f, only the content schematic of the technical scheme is expressed, and the relative size and relative position relationship of the structure are not actually expressed.
In some embodiments of the invention, because the electron conduction layer is a hard layer and other structural layers are soft layers, when the working electrode 4131 is damaged due to bending, the probability is that the electron conduction layer is bent and broken. Therefore, the working electrode unit 4131a can make the original whole electron conduction layer into an electron conduction layer unit with a smaller area. These electron conduction layer units share an anti-interference layer, an enzyme layer, an adjustment layer and a biocompatible layer.
In other embodiments of the invention, each working electrode unit 4131a can independently realize the detection function, that is, each working electrode unit 4131a contains an independent electron conduction layer, an anti-interference layer, an enzyme layer, an adjustment layer and a biocompatible layer.
In some embodiments of the invention, the electrode unit is a cubic structure as shown in Fig. 10f, which has dimensions of length (L) about 10～100um, width (K) about 1～50um, thickness (H) about 0.05～10um, and the adjacent two electrode units are arranged at intervals of 1～20um.
In some embodiments of the invention, each electrode may contain 10-500 electrode units, which depends on the area of the electrode, the area of the single electrode unit and the spacing of the electrode units. The specific number of electrode units in each electrode is not specially limited here.
In some embodiments of the invention, the area of each electrode in the sensor 41 is different, and there are different numbers of electrode units in the working electrode array, counter electrode array and reference electrode array. For example, there can be 25-120 working electrode units in the working electrode array, 50-150 counter electrode units in the counter electrode array and 15-75 reference electrode units in the reference electrode array.
In other embodiments of the invention, the electrode unit can be other three-dimensional structures, such as cylinder structure, prism structure, cone structure, etc.
In the preferred embodiment of the invention, the length*width*thickness of the electrode unit is 50um*30um*0.2um, there are 75 working electrode units 4131 in the working electrode array, 110 counter electrode units 4231 in the counter electrode array, 35 reference electrode units 4331 in the reference electrode array, and the spacing of each electrode unit is 10um. If more advanced laser etching technology is adopted, the area of electrode units and the spacing between electrode units can be made smaller, so that the possibility of electrode units being damaged becomes smaller and the detection performance is better.
In some embodiments of the invention, after each electrode unit is assembled into an electrode array, the approximate size of each electrode array is: the length*width*thickness of the working electrode array is 1.08mm*0.18mm*0.2um, the length*width*thickness of the counter electrode array is 1.52mm*0.18mm*0.2um, and the length*width*thickness of the reference electrode array is 0.51mm*0.18mm*0.2um.
In some embodiments of the invention, after changing the whole electrode into an array composed of electrode units, the insulating material that enhances the mechanical strength of the substrate can still be set in the corresponding area on the substrate 411. The setting method and setting area have been described in detail previously, and will not be repeated here.
In some embodiments of the invention, the electrode unit array can be shown in Fig. 10b. The substrate 411 can comprise a multi-layer substrate, and the electrode unit array is respectively set on the secondary-substrate of different layers. In some embodiments of the invention, when the electrode unit array is respectively set on the secondary-substrate of different layers, as shown in Fig. 10c, the substrates of each layer can be prefabricated first and then combined into a whole. In some embodiments of the invention, the electrode unit array can be set on the obverse side A and the reverse side B of the substrate 411, respectively, as shown in Fig. 10d. In other embodiments of the invention, when the electrode unit array is set on the obverse side A and reverse side B of the substrate 411, the substrate 411a of obverse side and the substrate 411b of reverse side can also be prefabricated first and then combined into a whole as shown in Fig. 10e.
Referring to Fig. 10g, in some embodiments of the invention, because the depth of the substrate 411 penetrating into the user’s subcutaneous skin is fixed, the area where the substrate 411 repeatedly bends with muscle creep is also fixed, or the area where the bending amplitude and frequency are relatively large on the substrate 411 is fixed, such as the easy-bending-area 416 in Fig. 10g. Generally, the flexible area 416 on the substrate 411 will preferentially reach the limit fatigue and be damaged compared with other areas. Therefore, the electrodes located on the substrate 411 can be distributed in a predetermined manner to avoid the flexible area 416, so as to prevent the electrodes from being damaged.
In some embodiments of the invention, the easy-bending-area 416 is not limited to one easy-bending-area 416 shown in Fig. 10g, but there may also be multiple easy-bending-areas, which are mainly determined by the material of the substrate 411 and the depth of penetration into the subcutaneous skin. Secondly, it is also related to the location of the substrate penetration into the user’s subcutaneous skin, the user’s movement mode, the thickness of the substrate and other reasons. Generally speaking, for the same substrate material, the penetration depth, the areas with large bending amplitude on the substrate 411 are fixed, and the electrodes should be set away from these easy-bending-areas.
In some embodiments of the invention, the easy-bending-area 416 is the middle section of the in vivo part Y. For example, when the penetration depth of in vivo part Y into the subcutaneous skin is 5mm, the easy-bending-area 416 is about 2.5mm away from the end of the substrate 411. In some embodiments of the invention, the easy-bending-area 416 may be an area 2.1～2.8mm away from the end of the in vivo part Y. The above values are for illustrative purposes only.
In some embodiments of the invention, when the substrate 411 comprises a multi-layer substrate or a double-sided substrate, there will also be some easy-bending-areas, which should be avoided when setting electrodes. In some embodiments of the invention, when at least one electrode is arranged on the reverse side of the substrate 411, the electrode arranged on the reverse side of the substrate 411 also avoids these bending-areas.
In some embodiments of the invention, while avoiding the easy-bending-area 416, the electrode can still be provided with an insulating material to enhance the mechanical strength of the substrate in the corresponding area on the substrate 411. The setting method and setting area have been described in detail previously, and will not be described here.
Referring to Fig. 10h and Fig. 10i, in some embodiments of the invention, the PAD 4111/4211/4311 corresponding to the electrode 4131/4231/4331 may be set on the reverse side B of the substrate 411, while the electrode 4131/4231/4331 is still set on the obverse side A of the substrate 411, or the PAD 4111/4211/4311 is set on the obverse side A of the substrate 411, and the electrode 4131/4231/4331 is set on the reverse side B of the substrate 411, that is, electrode 4131/4231/4331 and PAD 4111/4211/4311 are respectively set on the opposite side of substrate 411. Compared with electrode 4131/4231/4331 and PAD 4111/4211/4311 are respectively set on the same side of substrate 411, when sensor 41 is used, its in vitro part X may have different bending directions relative to the in vivo part Y. Based on this, the setting of insulating material on substrate 411 needs to be changed. For example, when the PADs 4111/4211/4311 are set on the reverse side B of the substrate 411, the in vitro part X is bent clockwise relative to the in vivo part Y. this bending way makes the sensor 41 need to be installed in the analyte detection device in a flip chip manner. For the technical scheme and application of the flip chip of the sensor 41, see the public patent pct/cn2022/0845, and will not be repeated here.
In some embodiments of the invention, the insulating material is also set in one of the PAD-reverse-area 412 of the PAD-area a or the electrode reverse area 413 of the electrode-area b. preferably, both the PAD-reverse-area 412 and the electrode reverse area 413 are set with insulating material. Unlike the above, the PAD-reverse-area 412 is located in the obverse side A of the substrate 411.
Referring to Fig. 10h, in some embodiments of the invention, the in vitro part X is bent clockwise relative to the in vivo part Y, and the insulating material can also be set in the bending-reverse-area 414 of the easy-bending-area c. In the embodiment of the invention, the bending-obverse-area 414 can be connected with the electrode reverse area 413 to form a coherent area (not shown in the figure) .
Referring to Fig. 10i, in other embodiments of the invention, the in vitro part X is bent counterclockwise relative to the in vivo part Y, and the insulating material can also be set in the bending-obverse-area 414 of the easy-bending-area c. In the embodiment of the invention, the bending-obverse-area 414 can be connected with the PAD-reverse-area 412 to form a coherent area (not shown in the figure) .
Referring to Fig. 10j, in some embodiments of the invention, not all PADs are located on the obverse side A or reverse side B of the substrate 411, but some PADs are located on the obverse side A of the substrate 411, while the rest PADs are located on the reverse side B of the substrate 411. On the one hand, the number of PADs on one side of the substrate 411 can be reduced, so as to increase the area of a single PAD. The PADs with larger area are better electrically connected with the circuit, the detection reliability of the sensor is improved. On the other hand, if an electrode is set on the reverse side B of the substrate 411, the PAD corresponding to this electrode should also be set on the reverse side B of the substrate 411, so that the wire can run on the reverse side B of the substrate 411.
In some embodiments of the invention, if the PADs are located on the opposite side of the substrate 411, for the circuit, it is necessary to design the electrical connection area for the PADs on the two sides of the substrate 411, which will increase the complexity of the circuit. Based on this, although some PADs are set on the reverse side B (obverse side A) of the substrate 411, the PADs of the reverse side B (obverse side A) can still be guided to the obverse side A (reverse side B) of the substrate 411, it is connected to the circuit with other PADs on the obverse side A (reverse side B) to simplify the complexity of the circuit.
In some embodiments of the invention, taking Fig. 10j as an example, the counter PAD 4211 corresponding to the counter electrode 4231 and the reference PAD 4311 corresponding to the reference electrode 4331 are set on the obverse side A of the substrate 411, while the working PAD 4111 corresponding to the working electrode 4131 is set on the reverse side B of the substrate 411. In addition, the first secondary-PAD 4111’ corresponding to the working PAD 4111 is also set on the obverse side A of the substrate 411, the first secondary-PAD 4111’ is connected to the circuit instead of the working PAD 4111 to simplify the complexity of the circuit, or the working PAD 4111 and the first secondary-PAD 4111’ are connected to the circuit at the same time to improve the reliability of the electrical connection between the PAD and the circuit.
In some embodiments of the invention, when the first secondary-PAD 4111’ is electrically connected to the circuit, the working PAD 4111 and the first secondary-PAD 4111’ need to establish an electrical connection to connect the working electrode 4131 to the circuit. In the general scheme, the area covered by the first secondary-PAD 4111’ and the working PAD 4111 at the same time on the substrate 411 is punched (not shown in the figure) , and conductive material is coated or sprayed in the hole. The first secondary-PAD 4111’ and the working PAD 4111 can be electrically connected, but this process requires that the first secondary-PAD 4111’ and the working PAD 4111 be aligned on the substrate 411, at least part of the first secondary-PAD 4111’ and the working PAD 4111 coincide on the substrate 411, otherwise the conductive material in the hole cannot contact the first secondary-PAD 4111’ and the working PAD 4111 at the same time, resulting in the failure of the fabrication of the sensor 41, which is common in the fabrication process of the sensor 41.
In view of the above problems, in some embodiments of the invention, a conductive material 4111” is arranged on the surface of the substrate 411 to establish an electrical connection between the first secondary-PAD 4111’ and the working PAD 4111, without the need to drill holes on the substrate 411. Specifically, the conductive material 4111” is set on the obverse side A, reverse side B and side of the substrate 411 through coating, spraying and other processes. The conductive material 4111” on the obverse side A and reverse side B is connected through the side of the substrate 411. The conductive material 4111” on the obverse side A is electrically connected with the first secondary-PAD 4111’, and the conductive material 4111” on the reverse side B is electrically connected with the working PAD 4111, in this way, the first secondary-PAD 4111’ and working PAD 4111 are electrically connected for the first time. In this scheme, the alignment of the first secondary-PAD 4111’ and the working PAD 4111 is not required, which simplifies the manufacturing difficulty of the sensor 41 and improves the manufacturing yield of the sensor 41.
In some embodiments of the invention, the conductive material 4111” located on the obverse side A of the substrate 411 and the conductive material 4111” located on the reverse side B are connected through the "side" of the substrate 411, where "side" refers to any edge of the substrate 411.
In some embodiments of the invention, the conductive material 4111” can be some common solder, such as solder, or some conductive metal or alloy, such as copper zinc alloy, platinum, etc.
In some embodiments of the invention, because PADs are set on the obverse side A and reverse side B of the substrate 411, the PAD-area a may not be set with insulating material, or as shown in Fig. 10j, the area 412 with a very small area is set with insulating material. Insulating materials can still be set in the reverse area 413 of the electrode and the bending-obverse-area 414.
Referring to Fig. 10k, in some embodiments of the invention, when the PADs are located on the opposite sides of the substrate 411, the obverse side A and reverse side B of the substrate 411 can be prefabricated first and then combined into a whole. Specifically, on the obverse side A of the substrate 411, the specific production scheme has been described in detail previously, and will not be repeated here.
Referring to Fig. 10l, in some embodiments of the invention, before setting the insulating material on the substrate 411, a protective layer 417 can also be set on the substrate 411. The protective layer 417 covers the whole of the substrate 411, but exposes the central area of PADs 4111/4211/4311 and electrodes 4131/4231/4331 and covers the edges of PADs 4111/4211/4311 and electrodes 4131/4231/4331. On the first hand, the protective layer 417 can enhance the mechanical strength of the substrate 411 and prolong the time when the substrate 411 is damaged. On the second hand, the protective layer 417 covers the edges of PADs 4111/4211/4311 and electrodes 4131/4231/4331 to prevent irregular edges from being exposed to cause signal noise and improve the stability of the detection signal. On the third hand, the electron conduction layer a of electrode 4131/4231/4331 is fixed on the substrate 411. Because the substrate 411 is repeatedly bent during use, the metal film of electron conduction layer a is inevitably separated from the substrate 411 and appears edge warping, bubbling or even falling off. After setting the protective layer 417, the protective layer 417 can also enhance the adhesion between the metal film of electron conduction layer a and the substrate 411, avoid edge warping and bubbling of the metal film, and improve the reliability of the sensor.
In some embodiments of the invention, the protective layer 417 has a thicker thickness than the electrode 4131/4231/4331, such as 1～25um. In this way, after coating the protective layer 417, pits are formed on the electrode 4131/4231/4331. The anti-interference layer, enzyme layer, adjustment layer, biocompatible layer and other structural layers of the electrode 4131/4231/4331 are located in the pits. The pits can accommodate more anti-interference layer, enzyme layer, adjustment layer and biocompatible layer, the sensitivity of electrode 4131/4231/4331 was improved. In the preferred embodiment of the invention, the thickness of the protective layer 417 is 0.1～200um. In a further preferred embodiment of the invention, the thickness of the protective layer 417 is 1～20um. The excessively thick protective layer 417 will reduce the softness of the substrate 411 and increase the user’s discomfort after penetrating into the user’s skin, while the excessively thin protective layer 417 is easy to be damaged.
In some embodiments of the invention, the protective layer 417 is made of one or more combinations of poly-tetrafluoroethylene, poly-ethylene, poly-vinyl chloride, acrylonitrile butadiene styrene copolymer, poly-methyl-methacrylate, poly-carbonate and poly-imide.
In some embodiments of the invention, the material of the protective layer 417 is poly-imide. After the poly-imide is properly heated to form a liquid, it is coated on the substrate 411 which is also poly-imide material, and the protective layer 417 can be formed after curing. The protective layer 417 of the same material has the same physical characteristics as the substrate 411, which can prevent the protective layer 417 from being damaged or falling off due to uneven stress or stress concentration on the substrate 411.
In some embodiments of the invention, after the protective layer 417 is made, the insulating material can also be set on the surface of the protective layer 417. The setting area and setting method of the insulating material have been described in detail previously, and will not be repeated here. Referring to Fig. 10m, in some embodiments of the invention, one or more of the working electrode 4131, the counter electrode 4231, and the reference electrode 4331 may have additional electrodes of the same name. For example, the working electrode 4131 comprises the first working electrode 4131α and the second working electrode 4131β. For another example, the working electrode 4131 comprises a first working electrode 4131α and the second working electrode 4131β at the same time, the counter electrode 4231 also comprises the first counter electrode 4231αand the second counter electrode 4231β.
In some embodiments of the invention, each electrode may have multiple electrodes with the same name, which can enrich and improve the functions of the sensor 41. For example, the first working electrode 4131α and the second working electrode 4131βcan be used relay when the first working electrode 4131α the second working electrode 4131β as a redundant electrode, it can replace the first working electrode 4131α by connecting the circuit and continuing the detection function, the service life of the sensor 41 is extended and the detection reliability is improved. For another example, the first working electrode 4131α and the second working electrode 4131β can be different enzyme layers to detect different analytes in the user’s body, such as blood glucose and blood ketone. For another example, the first working electrode 4131α and the second working electrode 4131β can be connected to the circuit at the same time, and its detection data are calibrated with each other, which improves the detection reliability. For another example, the first working electrode 4131α and the second working electrode 4131β can be used alternately, reducing the consumption of each electrode enzyme layer during use, and can extend the first working electrode 4131α and the second working electrode 4131β and further, the service life of sensor 41 is extended. For another example, the first working electrode 4131α and the second working electrode 4131β be connected to the circuit at the same time, and the analyte parameter signal is detected at the same time. After the detection signals of the two electrodes are superimposed, a stronger signal can be obtained, which enhances the anti-interference of the signal and improves the detection reliability.
In some embodiments of the invention, each electrode has at least one electrode with the same name. The first working electrode, the first counter electrode, and the first reference electrode form the first electrode-group, and the second working electrode, the second counter electrode, and the second reference electrode form the second electrode-group. With this push, each electrode-group can complete the blood glucose or other analyte detection function completely and independently. When using the sensor 41, each electrode-group can be used simultaneously or separately.
In some embodiments of the invention, the electrode with the same name is added on the substrate 411, which means that the corresponding PAD is also added. As shown in Fig. 10m, the first working PAD 4111α、the second working PAD 4111β、the counter PAD 4211 and the reference PAD 4311 are set on the PAD-area a. The area of PAD-area a is limited, and the larger the number of PADs means the smaller the area of each PAD, which will affect the reliability of the electrical connection between the PAD and the circuit. Based on this, with reference to Fig. 10j, part of the PADs are set on the reverse side B of the substrate 411, effectively using the limited area of the obverse side A and the reverse side B of the PAD-area a.
In some embodiments of the invention, when the first working electrode 4131α and the second working electrode 4131β stack the detection signal, the first working PAD 4111α and the second working PAD 4111β are simultaneously connected to the circuit. At this time, if it set electrical connection area the first working PAD 4111α and the second working PAD 4111β on the circuit, which will increase the complexity of the circuit, so the first working PAD 4111α and the second working PAD 4111β can establish electrical connection on the sensor 41 directly, and the circuit only needs to connect with one of the first working PAD 4111α and the second working PAD 4111β to achieve the function of the sensor 41, which will reduce the complexity of the circuit. The electrical connection between the first working PAD 4111α and the second working PAD 4111βshould refer to Fig. 10j and its corresponding description, and will not be repeated here.
Referring to Fig. 10n, in some embodiments of the invention, the first working electrode 4131α and the second working electrode 4131β share the PAD. Specifically, the first working electrode 4131α and the second working electrode 4131β electrically connect with the working PAD 4111 through wire 4121α and wire 4121βrespectively, and the detection signals of the first working electrode 4131α and the second working electrode 4131β are transmitted through the working PAD 4111, which can realize the function of signal enhancement.
Referring to Fig. 10o, in some embodiments of the invention, the first working electrode 4131α and the second working electrode 4131β share the wire. Specifically, the first working electrode 4131α and the second working electrode 4131β are electrically connected with the working PAD 4111 through the wire 4121, and the detection signals of the first working electrode 4131α and the second working electrode 4131β are transmitted through wire 4121 and PAD 4111, which can realize the function of signal enhancement. The first working electrode 4131α shares the wire 4121 with the second working electrode 4131β can reduce the number of wires set on the substrate 411, reduce the possibility of short circuit between wires, and improve the detection reliability.
In some embodiments of the invention, the electrode with the same name can be set on the same side of the substrate 411, which can reduce the manufacturing process steps and complexity.
In other embodiments of the invention, electrodes with the same name can be set on the opposite side of the substrate 411 to reduce the signal interference between electrodes with the same name.
In some embodiments of the invention, the shape of the insulating material on the substrate 411 is not limited to those shown in Fig. 10a to Fig. 10o, and the figure is only for illustration. All simple shape transformation, position transformation, material transformation, quantity transformation, layer number transformation, size transformation, etc. should be comprised in the protection scope of the scheme.
In some embodiments of the invention, the area where the "avoid" PAD and electrode mentioned above are located can refer to the structural area where the PAD and electrode need to be conductively connected, or the obverse side Area where the PAD and electrode are set on the substrate.
In some embodiments of the invention, the schemes involved in different illustrations may be applicable to each other. For example, the electrode unit array scheme involved in Fig. 10f can be applied to the double-sided electrode scheme involved in Fig. 10e, the substrate protective layer scheme involved in Fig. 10l, or other schemes, without limitation here.
To sum up, the invention discloses a highly reliability analyte sensor. The electrode is distributed on the surface of the in vivo part in a predetermined manner, avoiding the easy-bending-area on the substrate. When the substrate is repeatedly bent, the possibility of electrode breaking is reduced. At the same time, at least one layer of insulating material is post manufactured at least one area on the substrate, avoiding the area where the PAD and electrode are located, increasing the mechanical strength of the substrate of sensor, after the sensor is penetrated into the subcutaneous skin, when it bends with the muscle creep, the time for the substrate to reach the limit fatigue is extended, thus extending the service life of the sensor and improving the detection reliability of the sensor.
Although some specific embodiments of the invention have been detailed through examples, technicians in the field should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Persons skilled in the field should understand that the above embodiments may be modified without departing from the scope and spirit of the invention. The scope of the invention is limited by the attached claims.