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HK1125019B - Analytical contrivance with sterile protection for the lancet and test chamber - Google Patents

Analytical contrivance with sterile protection for the lancet and test chamber
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Publication number
HK1125019B
HK1125019BHK09103371.4AHK09103371AHK1125019BHK 1125019 BHK1125019 BHK 1125019BHK 09103371 AHK09103371 AHK 09103371AHK 1125019 BHK1125019 BHK 1125019B
Authority
HK
Hong Kong
Prior art keywords
lancet
needle
protective cover
tip
chamber
Prior art date
Application number
HK09103371.4A
Other languages
Chinese (zh)
Other versions
HK1125019A1 (en
Inventor
Fritz Hindelang
Karin Schwind
Original Assignee
F. Hoffmann-La Roche Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from EP05022830Aexternal-prioritypatent/EP1776925A1/en
Application filed by F. Hoffmann-La Roche AgfiledCriticalF. Hoffmann-La Roche Ag
Publication of HK1125019A1publicationCriticalpatent/HK1125019A1/en
Publication of HK1125019BpublicationCriticalpatent/HK1125019B/en

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Description

Analytical aid with a lancet and a test chamber
The invention relates to an analytical aid comprising a sterile-protected lancing device and an analytical test chamber. The invention further relates to a method for producing such an analysis aid.
Testing of blood samples in clinical diagnostics enables early and reliable identification of pathological conditions and targeted and informed control of physical conditions. The acquisition of a blood sample of an individual to be examined is always a prerequisite for a medical diagnosis of blood. While in the past several milliliters of blood of the person to be examined were often obtained by venipuncture for the analysis at a clinic or resident doctor for the purpose of carrying out several laboratory tests, today it is often sufficient to take few blood samples of less than one microliter for a single analysis for a single parameter. Such a small blood volume does not require laborious and painful venipuncture. In order to obtain a blood sample, it is sufficient to obtain a blood sample of a few microliters or less for analysis by puncturing the skin of the person to be examined, for example the finger pad or the earlobe, by means of a sterile and sharp lancet. This method is particularly suitable if the blood sample can be analysed immediately after the blood sample has been taken.
In the field of so-called "home monitoring", in other words, simple blood analysis by non-medical professionals themselves and at home, blood collection by diabetics on a regular basis several times a day for controlling blood glucose levels, lancers and devices adapted thereto (so-called blood collection devices, blood collection devices or-as described below-lancing aids) are provided, which make painless and reproducible blood collection possible. Furthermore, the use of these lancing devices with a lancing aid should also reduce the psychological difficulty in lancing the body of the user. This is particularly important for children who have diabetes and who regularly have blood glucose tests.
As examples of lancers and lancing aids, commercially available devices (lancing aids) are Glucolet from Bayer AG and Softclix from Roche Diagnostics. Such lancers and devices (lancing aids) are for example the subject of WO-A98/48695, EP-A0565970, US4,442,836 or US 5,554,166.
Today the hands-on determination of blood glucose (so-called "home monitoring") has become a worldwide common approach in diabetes management. The prior art blood glucose meters, for example the Accu-Chek Sensor (roche diagnostics) are formed by a measuring device into which a test element (test strip, Sensor) is inserted. This test strip is in contact with the drop of blood. The blood drop is previously taken from the finger belly or another body part by means of a puncture aid. The large number of system components (lancet, lancing aid, test strip and measuring device) requires a lot of space and results in a relatively complex operation. There are also systems with a higher degree of integration, and therefore the operation is simpler. For example, Accu Chek Compact (of Roche Diagnostics), Glucometer Dex (of Bayer Diagnostics) and Sift-Sense (of Medisense) belong thereto. In the first two systems described above, the test strip is stored in the measuring device for testing use.
The next step in achieving miniaturization is to combine multiple functions or multiple functional components into a single analytical aid (Disposable). By suitably combining the lancing process with the sensor-based concentration analysis on the test strip, the process sequence can be significantly simplified, for example. In this respect, the following examples are given in the prior art:
EP-B0199484 (Audio Bionics) describes an analytical aid ("Disposable", abbreviated to Dispo), which has an integrated lancing device, which is implemented in a device (see FIG. 9). The lancet is again pulled back after lancing by a special spring-mounted lancet mechanism ("spring-mounted lancet means"). The analytical aids comprise so-called Wick means ("Wick means") by which the sample liquid is guided from the body surface to the analysis region, i.e. the test field of the optical analysis.
One method is described in US6,143,164 (e.heller & Comp.). In this method, a body opening is created (for example by a small puncture or incision in the skin), and the body fluid is subsequently conveyed into the sensor, where the presence of the analyte is tested. For this purpose, US6,143,164 discloses an analysis aid. In this analytical aid, the lancing device is arranged on the sensor test strip. The sample liquid is transported from the body opening to the actual detection element of the sensor, for example again by the "wick method" or also by the capillary blood gap/channel.
US4,627,445 describes an integrated system. The system has only one opening for both the lancet to extend out and for blood to be drawn into the instrument. However, in this invention, no sterility protection is used to seal off the lancet tip and opening.
Furthermore, the integration of the test element has led to the development of new protective components for the lancet. Because the use of a lancet in an integrated system is not the same as the operational flow of a manual lancet, a possibility must be found that can maintain the sterility of the lancet, but can provide ready access. In an integrated system, there is no longer any need to remove the sterile protection device by the user before use, as is the case with conventional manual lancets. In this respect, the prior art has the following solutions:
US 2003153939 describes a protection mechanism for a lancet or a lancet tip thereof. The retention mechanism keeps the tip sterile until the puncturing procedure and is then responsible for hygienic preservation. The protective means is penetrated during the puncturing process and the lancet is surrounded by the protective body again after the puncturing process, so that no contamination of the environment is formed by the use of the lancet.
US 2003050573 relates to a lancet protection device in an integrated system. The protective device maintains the sterility of the lancet tip until the lancing process. In which case the sterile lancet exits the outlet. This outlet is located separate from the opening from which the blood sample is taken.
A disadvantage of the known analytical aids is the lack of a combination of different functions, such as sterility protection of the lancet, sterility protection of the test chamber, as short a stroke as possible for the delivery of the blood sample and the patient not having to participate. Thus, while there are some aspects of the individual aspects, there is no combination of all of these requirements. For example, in the prior art, the sealing material is penetrated when the housing opening is sealed. And because the closure material is not removable, an additional opening must be created to receive the blood sample. This requires a complex structure for the integrated system to work with sterility protection measures. This complex structure provides for the puncturing process and the blood sample reception to be spatially separated, thus forcing the patient to actively participate in the blood sampling process. This means a great loss in comfort and creates great difficulties for patients with poor vision.
The object of the invention is therefore to eliminate these disadvantages of the prior art. In particular, the object of the invention is to provide an analytical aid (or its synonym "disposables", abbreviation "Dispos") which does not have the disadvantages of the prior art. In particular, it should be ensured that the sterility of the lancet during use is ensured by the analytical aid according to the invention while the lancet and the test element are combined. It is also intended to ensure the shortest possible path of the liquid to be analyzed from the opening of the analytical aid to the test element. This system has a high level of operational comfort for the patient, who does not have to be careful about taking blood after the puncture.
It is also an object of the invention to provide an analytical aid having a lancet. In these auxiliary devices, at least the lancet tip is stored aseptically, i.e., sterilely, until the time of use, in the unused state, and hygienically also in the used state. It is desirable to accomplish this task without requiring the user to take separate steps in order to hygienically preserve them. Furthermore, the user is prevented from unintentionally pricking himself with the lancet, in particular with a used lancet. In addition, the transport of the blood sample from the blood collection site to the blood testing site can also be simplified.
These objects are achieved by the subject matter of the present invention as set forth in the independent claims. Preferred embodiments are the subject of the dependent claims.
A first subject of the invention is an analytical aid comprising a lancet having a lancet needle with a tip and a protective cap as preferred components. The protective cap completely surrounds the lancet needle at least in the region of the tip. In which case the lancet needle may move relative to the protective shield. Wherein the protective cover may be constructed of different materials that are pierceable and into which the sharp end of the lancet needle may be embedded. The analytical support device also comprises an analytical test element, which is formed by a chamber. The chamber includes a detection element having a reagent system. This chamber has an opening. The lancet is moved through the opening during lancing. This opening is closed by a protective cover of the lancet needle.
Finally, the method for producing these analytical aids is the subject of the present invention.
The solution according to the invention is preferably formed by a miniaturized analytical aid. Three of these functions, namely the lancing, the delivery of the blood sample from the wound created by the lancing to the test element, and the detection of the analyte, are integrated into one entity.
The base body of the analytical aid according to the invention is formed by a rigid plastic body, preferably with a cavity, the outer shape of which is adapted accordingly to the purpose of closing the housing opening. In this plastic material, the lancet needle is embedded in such a way that its tip preferably does not protrude beyond the front edge of the base body. This base body can therefore also be called a protective cover. In a preferred embodiment, the base body has tabs. These tabs serve to fix the needle in the base body and to guide it during the puncturing process. However, it is preferred that the main part of the needle is not connected to the base body to reduce the friction of the puncturing movement. It is preferable to minimize the contact area of the needle and the protective cover and to appropriately perform a pretreatment such as silicidation.
The analysis assisting mechanism is composed of a housing. In this housing, a lancet needle with a protective cap and a test element are arranged. At least one electrode can optionally be arranged in the test chamber during the electrochemical measurement. In a preferred embodiment the housing is formed by two housing parts. The housing parts can be produced from different plastics by injection molding. The polymer can be selected from polyesters, polycarbonates, polyvinyl chloride, plexiglass, copolyesters and mixtures thereof, without being restricted thereto. In the case of an optical analysis test element, a part of the housing is composed of a transparent material.
The lancets according to the present invention are designed for single use and may therefore be referred to as disposable lancets or disposable lancets. The lancet of the present invention comprises a needle (lancet needle) having a pointed end. This needle typically has a length of several millimeters (mm) to several centimeters (cm) and has an elongated shape. Typically such needles have a cylindrical shape, since such needle shapes can be manufactured particularly well. However, differently shaped needle shapes are also possible. The tip region of the needle comprises the needle tip. The needle tip penetrates into the tissue when the lancet is used as intended. The tip of the lancet needle is thus part of the lancet, it comes into contact with the skin of the individual to be punctured and, if necessary, scratches the skin and thus causes the outflow of body fluids, in particular blood, or fluids in the interstitial spaces of the tissue.
The tip of the lancet needle may be, for example, rotationally symmetric, as is typically the case in pins. It has however proved advantageous if one or more abrasion sites are provided on the needle tip. The edge extending toward the tip, which is inclined to the longitudinal axis of the needle, which edge is present in this case acts as a sharp blade during the puncture and makes the puncture procedure less painful than a needle without a burr.
The lancet needle of the lancet according to the present invention is made of a material that is sufficiently rigid to withstand mechanical stresses or other stresses that may occur during the process steps during the lancing process without deforming. Furthermore, efforts must be made so that the material must not break off into small particles or flake off during the piercing process. Finally, the material of the needle should also be such that the needle tip is sufficiently sharp and the edge of the needle tip can also be sharpened sufficiently sharply. Materials suitable for use as lancet needles are primarily metals, particularly high quality steel. If the properties of the lancet as a level gauge and counter electrode are abandoned, it is also conceivable for the needle to be composed of silicon, ceramic or plastic. Particularly preferred are high grade steel needles.
In an embodiment according to the invention, at least the tip of the lancet needle of the lancet according to the invention is surrounded by a protective cover. The main feature is that the protective cap is made of a material that is penetrable by the lancet tip in the region of the tip of the lancet needle. If the protective cover is made of an elastic material, it preferably completely surrounds the lancet tip. Such that the lancet tip is isolated from the environment. The advantage of those elastic materials of the protective cover which may form the protective cover in different embodiments completely or partly is that they are soft, deformable, can be penetrated by the lancet needle with its tip and do not injure the tip. When the protective cover is non-elastic, it is preferred that the lancet tip is surrounded by the protective cover such that a cavity exists between the lancet tip and the protective cover wall. The wall thickness of the protective cap material is designed such that no deformation or abrasion of the sharpened edge of the lancet tip occurs during the puncturing operation.
During the puncturing process, the lancet needle is moved along its longitudinal axis relative to the protective cap and exits the housing with its tip through the protective cap in order to penetrate into the skin of the individual to be tested for blood removal.
The resilient material of the protective cover that completely encloses the tip of the lancet needle ensures sterility prior to use of the lancet needle, preferably until immediately prior to use. The elastic material is therefore germ-tight against the ingress or leakage of pathogenic bacteria when the lancet needle is not in use. The resilient material also provides a mechanical protection for the lancet tip and thus prevents inadvertent damage to the lancet tip.
Suitable elastic materials for the production of the protective cover according to the invention are rubber, raw rubber, silicon, elastomers, in particular thermoplastic elastomers. These materials have basic characteristics for use in the present invention: it is soft, deformable, easily pierced by a lancet needle without damaging the tip, and sealingly encompasses the unused lancet tip. In addition, these materials are suitable for use in the die casting process for mass production of lancets.
Thermoplastic elastomers, also known as elastoplastics or thermoplastics or thermoplastic green rubbers, ideally have a combination of the service properties of elastomers and the processing properties of thermoplastics. Examples of such thermoplastic elastomers are styrene-Oligoblock copolymers (so-called TPE-S), thermoplastic polyolefins (TPE-O), thermoplastic polyurethanes (TPE-u), thermoplastic copolyesters (TPE) and thermoplastic copolyamides (TPE-A). In particular, thermoplastic elastomers based on styrene-ethylene-butylene-styrene polymers (SEBS polymers, for example Evoprene from Evode Plastics, or Thermolast K from Gummiwerk Kraiburg) have proven suitable as elastomers.
The lancet needle moves relative to the protective shield during the lancing process. In this case, the protective cap is preferably fixed in its position by the puncture aid or the puncture device. The lancet needle may be specially shaped for its actuation. For example, it can have a needle at its end opposite the tip, or, in addition to a protective cap surrounding the tip, another lancet body or a lancet holder, which can be grasped by the drive element of the puncture-assisting mechanism. The needle or an additional lancet holder can interact in a suitable manner with a corresponding drive in the lancing device (lancing auxiliary mechanism). These mechanisms are commonly referred to as needle drives. Such drive devices are sufficiently familiar to the person skilled in the art, for example from patent applications US6,783,537B 1 or EP 1336375.
In order to increase the stability of the elastic material, the elastic material can be connected to a rigid material, for example a rigid plastic. The resilient material may be secured, for example, on its outer side which contacts the tip of the lancet needle, by a layer of rigid material, such as a rigid plastic. It is also possible to manufacture the protection of the lancet only in the region of the lancet tip from an elastic material, while at other locations the envelope of the lancet is manufactured from a conventional rigid plastic. In this case, the elastic material and the rigid material can be bonded to one another or connected to one another by means of a die-casting process, for example a two-component die-casting process. The rigid material of the lancet enclosure in this case has the responsibility of taking care of the mechanical stability of the elastic material during the puncturing process and of facilitating the fixation of the elastic part of the protective cover during the puncturing by the puncturing aid mechanism. The rigid material may also be part of a test element, for example a capillary gap test element, as described in WO 99/29429. In another embodiment the entire boot may be made of a rigid material.
The patient and the protective cover do not contact, or only partially contact, during the puncturing process. Instead, the patient places his finger on an opening of the housing, which is preferably not arranged on the side of the coupling of the drive and of the analytical aid and the measuring device. After the fingers are placed, the patient may actuate a mechanism that causes the lancet to move from a resting state to an active state and back to the resting state.
In this case, the lancet is moved out of the housing with its distal end, i.e. with its tip, through the opening for a short time. During its return to the housing, the lancet pulls back the protective cap, which remains in the housing during the puncturing process, together with the protective cap by means of a gripping device coupled to the lancet body or connected to it.
According to the invention, the transport of blood from the puncture site to the detection site of the wound/lancet is achieved as follows: the blood is preferably delivered virtually "automatically" without the need for the user of the analytical aid according to the invention to manually carry out this. For this purpose, the analytical aids can have means for conveying the sample liquid. Preferably, these means can be designed as capillary-acting gaps or channels, for example, in a rigid matrix or as an absorbent matrix material. These two basic methods can also be combined, for example, by first conducting the blood through a capillary channel and being absorbed by the absorbent matrix material and then being transferred into the test chamber.
It has proven to be particularly suitable for use as an absorbent matrix material in the sense of the present invention for an absorbent felt, paper, cotton core or textile.
In a preferred embodiment, the base body of the analytical aid, preferably the test chamber, has a means for transporting the liquid sample. This mechanism may be a wick (Docht) that is absorbent and opens into the chamber, or preferably a shaped capillary gap. The void also serves as the outlet for the lancet. This measure makes it possible to dispense with the movement of the analytical aids when the blood is being received. The geometry of the inlet is designed such that the formed drop of blood is as easy to receive and inject as possible, for example as a funnel or incision. Capillary action is then used to draw in the desired amount of blood. This blood volume can obviously be below 1 microliter. On this way, the blood enters the chamber and passes to the detection zone, where it reacts with the test detection reagent, wherein an analyzable electrical signal, or a color change, is generated. The capillary gap can be formed into the plastic during casting or inserted into the plastic body afterwards, for example pressed or milled. The suction of the test droplets into the capillary channel is particularly preferably achieved by hydrophilizing the surface exposed by the recesses and directly adjoining the surface-active region at least in the direction of the capillary transport channel.
In this respect, the hydrophilic surface is a water-absorbing surface. Water-like samples, which also include blood, are well distributed on these surfaces. In addition, these surfaces are characterized by the fact that water droplets form sharp edges-or contact angles-on the interface. On the other hand, an obtuse edge angle is formed at the interface between the water droplet and the surface on the hydrophobic, i.e. water-repellent, surface. This property of the capillary tube to absorb liquid arises from the wettability of the channel surface with liquid. For a water sample this means that the capillary should be made of a material whose surface tension is close to or exceeds that of water (72 mN/m).
Materials which are sufficiently hydrophilic for the production of capillaries which rapidly absorb water-like samples are, for example, glass, metal or ceramics. However, these materials are not suitable for use as test carriers because they have several serious disadvantages. For example glass or ceramics, run the risk of breakage or, when large amounts of metal are used, their surface properties change over time. Plastic films or plastic molded parts are therefore often used in the production of test elements. The plastics used in this case generally do not exceed a surface tension of 45 mN/m. Even the most hydrophilic plastics used, such as polymethyl methacrylate (PMMA) or Polyamide (PA), can only enter capillaries which normally form very slow absorption. Capillaries made of hydrophobic plastics such as Polystyrene (PS), polypropylene (PP) or Polyethylene (PE) do not absorb substantially watery samples. The plastic used as the construction material for the test element must therefore be hydrophilically structured, i.e. hydrophilized, with surface-active channels.
Hydrophilization of the capillary channel surfaces can be achieved in an ideal manner by using a hydrophilic material in its production, which material, however, does not absorb or substantially does not absorb the sample liquid itself. Where this is not the case, hydrophilization can be achieved by suitable application of a hydrophilic layer, which is stable and inert with respect to the sample material, to the hydrophobic or only slightly hydrophilic surface, for example by covalent bonding of a hydrophilic polymer formed by photochemical reactions to the plastic surface, by application of a coating containing wetting agents, or by coating the surface with a nanocomposite by means of the Sol-Gel (Sol-Gel) process. Furthermore, the hydrophilicity can be increased by heat treatment, physical or chemical treatment of the surface. For example, plasma treatment of the surface is also included. This can be achieved, for example, by means of energetic oxygen or other polarising media.
It is particularly preferred to achieve hydrophilization by using thin-layer oxidized aluminum. These thin layers are either applied directly to the desired structural parts of the test element, for example by vacuum evaporation of the workpiece with metallic aluminum and subsequent oxidation of the metal, or the test carrier is constructed in the form of a metal film or a metal-coated plastic film, which must also be oxidized in order to achieve the desired hydrophilization. In this case a metal layer thickness of 1 to 500nm is sufficient. The metal layer must then be oxidized in order to form an oxidized form, with the oxidation, in addition to electrochemical anodic oxidation, especially in current steam or poaching oxidation, proving to be a particularly suitable method. The thickness of the oxide layer thus obtained is between 0.1 and 500nm, preferably between 10 and 100nm, depending on the method. Although in principle it is possible to achieve a greater layer thickness, whether it be a metal layer or an oxide layer, this has no other advantageous effect.
In a preferred embodiment, the detection element of the analytical test element according to the invention comprises all the reagents and, if appropriate, auxiliary agents necessary for the detection reaction of the analyte of interest in the sample. The detection element may contain only a portion of the reagent or adjuvant. These reagents and adjuvants are familiar to the skilled worker in the analysis of test elements and diagnostic test carriers. For analytes that should be detected enzymatically, for example, enzymes, enzyme matrices, indicators, buffer salts, inert fillers, and the like are included in the detection element. The detection element may be of a single-layer structure or a multilayer structure, and may include an inert carrier if necessary, which is preferably disposed on the side of the detection element not in contact with the sample. In a particularly preferred case, in which the detection reaction leads to an observable color change, wherein a color change in this respect can be understood as both the appearance of a color and the disappearance of a color, it must be ensured that the support allows visual or optical observation of the detection reaction by taking appropriate measures. For this purpose, the carrier material of the detection element can itself be transparent, for example a transparent plastic film, for example a polycarbonate film, or have transparent recesses on the detection side. In addition to these detection reactions which lead to a color change, the skilled worker is aware of further detection principles which can be implemented with the described test elements, for example electrochemical sensors.
At least one electrode is disposed in the test chamber for electrochemical detection of the analyte. This electrode is connected to the measuring device via a contact on the analytical aid. In which case the lancet may act as the second electrode. This lancet is preferably connected to the measuring device by spring contacts. But may also be a rigid contact of the lancet and the measuring device. This measurement can be carried out both with direct current and with alternating current. Furthermore, there is the possibility of using the lancet as a level controller. This is also possible by means of spring contacts. This spring contact allows the lancet to be connected to a measuring device after use of the lancet, and the current strength or voltage changes when the lancet comes into contact with the incoming liquid.
The test chamber includes both the lancet tip with the protective cover and the detection reagents required for the test and the electrodes used in the electrochemical test. The test chamber is dimensioned such that a minimum volume of test liquid is required. Preferably 1. mu.l or less. For optimal delivery of the liquid to the test chamber through the outlet, the test chamber is preferably made of a hydrophilic material.
The test chamber may have different shapes. Thus the chamber may be square or rectangular. The chamber may also be rounded or an elliptical hemisphere. The chamber has at least one opening. The lancet exits through the opening when activated. In the rest state before use, this opening is closed by a protective cap which surrounds the lancet tip. The chamber needs to be further vented after the lancet is activated to gain capillary action into the chamber. This may be ensured by a second opening in the chamber or by a vent hole provided in the lancet holder. This lancet holder is closed by a membrane or other closure prior to use of the lancet. The geometry and volume of the chamber is related to the number of electrodes in the chamber. The number of electrodes is determined according to the use mode of the auxiliary mechanism. At least one electrode is provided in the test chamber for electrochemical analysis, wherein the lancing device can be used as a counter electrode or a reference electrode. Other electrodes may also be supplemented. More than one analyte can be determined independently of each other by adding some other electrode. Among these analytes may be, for example, constituents of the blood such as cholesterol, triglycerides, coagulation factors and other blood parameters. The volume of the chamber is between 100nl and 1000nl, but it can be larger when multiple electrodes are used. In a preferred embodiment, the volume is between 300nl and 600nl, particularly preferably 500 nl. The electrodes and their contacts are made of a conductive material, such as conductive plastic or metal. When using the lancet as an electrode, either the electrode and its contacts or the lancet can be constructed of an electrically conductive material, such as aluminum, lead, iron, gallium, gold, indium, iridium, carbon (e.g., graphite), cobalt, copper, magnesium, nickel, niobium, osmium, palladium, platinum, mercury (used as an amalgam), rhenium, rhodium, selenium, silicon (e.g., highly added polysilicon), silver, tantalum, titanium, uranium, vanadium, tungsten, tin, zinc, zirconium, mixtures thereof or alloys thereof, oxides of the listed elements or mixtures of metals. Preferably the contacts and electrodes comprise gold, platinum, palladium, indium, or mixtures or alloys of these metals. In which case the contact points may be made of a different material than the electrodes. Likewise, the lancet tip may also have a different composition than the remainder of the lancet body. In a preferred embodiment, a silver/silver halide electrode is used as the reference electrode and a (e.g. screen-printed) graphite electrode is used as the workpiece electrode.
In the optical detection of chemical transformations in the test chamber, the housing of the device has at least one optically transparent housing wall. The transparent housing wall is arranged either below or above the test agent. If only optical measurements are to be made, no electrodes need to be provided in the test chamber. It is also possible to combine electrochemical and optical measurements. Light is directed at the test area during optical inspection. The interaction of the test zone and the liquid can be measured in terms of reflection or transmission. When using the transmission measurement method, an optically transparent housing wall is used both on the incident side and on the detection side. The detection element is a component of the test element and contains a detection reagent, which is fixed on the transparent surface of the test chamber during optical detection. The optical characteristic changes when the test liquid reacts with the test agent in the test element, which changes are detectable by means of an optical module. The optical module may be a photosensor or a photomultiplier or an optical sensor unit as is known in the art. The radiation source may also be one of the radiation sources disclosed in the prior art. The retracted lancet can also be used as a level gauge when optical measurement methods are used.
The gripping means for the retraction of the protective cap and/or the retraction of the further seal can have different embodiments. The present invention is embodied in the practice of roughening the surface of the lancet at appropriate locations on the body of the lancet. By this means, sufficient friction is generated when the roughened surface and the sealing body are in contact, so that the sealing body remains attached to it when the lancet is pulled back.
A second embodiment according to the present invention is a grapple. The catch can again have different embodiments. The principle is that when the lancet is extended to its maximum, the sealing body hooks over the barb of the lancet body so that the sealing body is pulled back with the lancet. The catch hook can also consist of a bristle-shaped molding or of the hook of the lancet. These hooks align their orientation with the proximal body end of the lancet. The hooks may be constructed of different, preferably non-deformable materials, such as metals, ceramics or polymers, preferably metals.
Another embodiment of the gripping means is a gripper hook which is movable on the sealing body and which surrounds the sealing body. By surrounding the seal, the seal is caused to return when it is returned after the lancet has been activated. This catch is connected to the lancet body by a fixing member. The catch hook has at least one arm which extends in the direction of the lancet tip and is provided with a hook at the distal end. The hook is rolled to cover the seal when the lancet is maximally deflected. In order to reliably grip these seals, an embodiment is chosen which is preferably provided with at least two arms.
This catch or also the roughened surface on the lancet pulls both the protective cover and the other provided seals back into the housing. The outlet and the other openings for venting the test chamber are opened by the pulled-back seal. This sealing of the test chamber is to prevent contamination of the electrodes and test reagents during storage. The protective cover furthermore prevents the patient from inadvertently coming into contact with the lancet prematurely.
The function of the analytical aids according to the invention is generally described below:
1. the analytical aid is inserted into the receiving device of the (blood glucose) measuring device and is fixed thereto. For the analysis support means of the cassette, the cassette of the analysis support means is inserted into the measuring device.
2. The drive mechanism of the puncture unit is tensioned and coupled to the drive means of the analytical aid.
3. When the analysis aid is fixed to the measuring device, the contacts of the analysis aid come into contact with the power supply in the measuring device.
4. The user touches the opening of the analytical aid with a finger or with the body part to be measured.
5. During the triggering of the puncturing process the needle is moved forward and in this case from the opening through the protective cap at high speed. The whole puncturing process is completed in the range of less than a few milliseconds.
6. The needle is pulled back again after the skin penetration is completed. In this case, the gripping device provided on the lancet pulls the protective cap and, if necessary, the further sealing element back together. The drive is also decoupled if necessary.
a) When the lancet is used as a counter electrode, the lancet is connected to an additional spring contact. This spring contact may be integrated into the drive unit.
(additionally) the user contacts the opening of the auxiliary device on his receiving device, so that the suction port (e.g. capillary tube) can absorb the drop of blood.
8. The blood in the analysis assistance device is conveyed by the suction effect of the device for conveying the sample liquid into the region of the test chamber in which the test element with the detection element is arranged.
9. The blood component to be detected and the detection reagent react in the test element. This reaction is detected, for example, photometrically or electrochemically.
10. The measurement results are calculated from the electronic data and displayed to the user optically or acoustically.
11. For the analysis support mechanism of the cartridge, the cartridge is first set. For disposable analytical aids, the used analytical aids are discarded or removed by hand.
Measuring devices known to the skilled person, which have different features, such as algorithms for analysis, and different power supplies for supplying power to the analysis aids, are described in the following applications: U.S.4,963,814; U.S.4,999,632; U.S.4,999,582; U.S.5,243,516; U.S.5,352,351; U.S.5,366,609; U.S.5,405,511; U.S.5,438,271.
The production of the analytical aids according to the invention can in principle be carried out in the following simple steps:
1. the housing parts are die cast.
2. A die-cast base body (protective cap) with an embedded lancet (possibly together with a "needle", i.e. a thickened portion that can be grasped by the lancing device).
3. The needle tip was injection molded with soft plastic.
4. The "raw analytical aids" are sterilized, for example, by means of ion radiation.
Preferably, these "raw analytical aids" are present as strips which are to be separated into individual analytical aids by, for example, cutting or punching.
5. The electrodes are mounted (sprayed, pressed, etc.) or embedded (laser ablation, acid etching, die casting, etc.) into the housing.
6. A test element with a detection element is mounted on the electrodes in the housing.
7. The test is carried out, i.e. the "raw analytical aids" are connected to the housing.
8. The housing is closed and packaged.
Whether the "raw analytical aids" according to the invention are produced as a web or strip in a continuous production process, either in batches or in single pieces, the lancet and the housing are connected to one another before or after the lancet is sterilized. Sterilization after installation allows the test reagents to be adequately covered during sterilization, otherwise damage to the reagents may occur.
Finally, the subject matter of the invention is the use of a plastic material as a component of a lancet of an analytical aid, wherein this plastic material is used to maintain the sterility of at least the tip of the lancet needle in the unused state.
The use of an elastic material to protect the tip of the lancet needle according to the present invention may ensure sterility of the unused lancet tip.
Sterility of the lancet in the unused state can be achieved by taking suitable measures, such as treatment with ionizing radiation. The lancet tips can also be kept sterile by corresponding protective caps, which also contain an elastic material.
The use of a protective cap according to the invention enables at least an additional sealing of the opening of the test chamber. The at least one opening serves both as an outlet for the lancet and as an inlet for body fluid.
The invention has the following advantages:
in all embodiments the lancet needle tip is pathogen protected in the unused state, i.e. the germs cannot reach the lancet tip until just before the use of the lancet. The lancet tip is aseptically stored for long periods of time after proper sterilization.
The sterility of the lancet tip is also ensured in later manufacturing steps, such as the connection of the lancet and the test element. Including protection of sensitive needle tips against mechanical influences (bending, etc.).
-preventing the user of the analytical aid according to the invention from being accidentally injured by an unused lancet needle. This also applies to other people.
The test chamber is sealed prior to use of the lancet.
The opening of the test chamber is closed only by the protective cover or in combination with another seal.
The analytical aids according to the invention can be produced in large quantities in a cost-effective manner by conventional production methods.
The analytical support according to the invention is already largely miniaturized, so that it is suitable for use in compact automation systems.
Known versions of electrochemical or optical sensors can be used as analytical test elements.
In electrochemical measurements, the lancet (when it is made of an electrically conductive material) can be used as a level gauge and/or as a counter electrode.
Brief description of the drawings
FIG. 1 (a-c): a schematic side view of an analytical aid with 2 electrodes in an unused state, an active state and a measuring state;
FIG. 1 d: a schematic top view of an analytical aid with 4 electrodes;
FIG. 2 (a-d): schematic representation of the grasping means (roughened surface) on the lancet needle, before (a) and after (b) use, and before (c) and after (d) use with an additional seal;
fig. 2(e, f): a schematic view of another grasping device (grasping bristles) on the lancet needle, before (e) and after (f) use;
FIG. 3 (a-d): schematic representation of a lancet with a protective cover and a catch (a, b) and a lancet with a protective cover, a seal and a catch (c, d), in a rest state (a, c) and in a use state (b, d);
fig. 3(e, f): schematic contact of a lancet holder, wherein (a) is a side view before actuation and (b) is a top view after actuation;
FIG. 4 (a-c): schematic representation of the use of the lancet as a level controller (a) or as a counter electrode (b) or a combination of level measurement and counter electrode (c);
FIG. 5 (a-d): schematic representation of different geometries of the test chamber, such as rectangular (a), fully elliptical (b), or semi-elliptical (c);
FIG. 6: a schematic view of a protective cover with additional sealing function to the second opening.
Description of the drawings
Fig. 1a-c show three different operating states of the analytical aids. Fig. 1a shows the analytical aid (1) with the lancet (2) in the unused state. Wherein the tip (12) of the lancet is surrounded by a protective cover (5). In this case, the lancet tip (12) and the at least one electrode (3) are located in the test chamber (8). The contact (4) forms the connection of the electrode (3) to the measuring device. The test chamber (8) has at least two openings (9, 10), wherein the opening (9) is sealed by a protective cap (5), and the opening (10) is either also sealed by the protective cap (5) or is sealed by a further seal (6). Fig. 1b shows the analytical aid in use. The fastening element (13) has a recess (13a) on one side, which serves to ensure the connection to a drive (not shown here). In this case, the lancet (2) exits the housing through the opening (9). Fig. 1c shows the lancet (2) after use in the analytical aid (1). In this case, the lancet (2) pulls the protective cap (5) and the sealing element (6) together to such an extent that both the opening (9) and the opening (10) are open. In this state the proximal end of the lancet is connected to the contact (7). Fig. 1d shows an analytical support (1) with a plurality of electrodes (3). In this case there are 4 electrodes in total. More electrodes may also be provided. They are used for carrying out controlled measurements or, more generally, for measuring analytes in sample liquids. In this embodiment, the geometry of the test chamber is varied, so that the lancet holder (13) additionally has a recess (13 a). This recess (13a) is used to ensure venting of the test chamber after lancet action. In this embodiment the fixing element (13) has a vent channel (not shown here) from the recess (13a) to the test chamber. The sterility of the test chamber is ensured by the closure of this recess (13a) prior to the lancet action. This closure (not shown here) is removed or broken when activated.
Fig. 2a-f also show different states of action of the lancet (2). The operating principle of the gripping device (11) is shown here in different gripping methods. Fig. 2a shows the lancet (2) with the gripping device (11) in a resting state. The gripping device is arranged between the proximal body end and the distal body end of the lancing device (2). It is arranged such that it reaches the protective cap (5) when the lancet (2) is actuated, since the protective cap (5) has a larger diameter than the housing opening (9) and therefore further forward movement of the protective cap (5) is prevented. The catching device (11) reaches the protective cap (5) when the lancet (2) is maximally deflected, and the protective cap (5) is also pulled back together by the interaction of the catching device (11) and the protective cap (5) when the lancet (2) is pulled back. The gripping means (11) preferably has a rough surface. Due to friction, the protective cap (5) and also the second seal (6) may hang on this surface, as shown in fig. 2a to 2d, for example. Fig. 2c shows the second seal (6). The seal (6) is a second opening (10) for closing the test chamber prior to actuation of the lancet. Fig. 2e shows a further embodiment of the gripping device (11). This gripping device is realized here by gripping the bristles. Another embodiment of the gripping device (11) is a gripper hook. Figure 3a shows such a grapple. This catch is fixed to the lancet by means of a fixing element (13) and has an opening (11a) towards the lancet tip (12). The opening (11a) has such a shape that it grips the protective cap (5) when the lancet (2) is maximally deflected and is also fed back when the lancet (2) is pulled back. The grapple has at least one arm (11b) with a barb disposed at a distal end of the arm. The barb moves on the protective cover (5) when the lancet (2) is actuated and thus grips the protective cover (5). Fig. 3b and 3d show this grasping device after the lancet (2) has been activated. In these figures, the catch is associated with two catch arms (11b) and can therefore enclose the protective cap (5) and the seal (6) on both sides. The grapple may have more than 2 grapple arms (11 b). Fig. 3c and 3d show the principle of this catch with at least one arm (11b) with an additional seal (6). Wherein figure 3c shows the lancet in a resting state prior to activation. Fig. 3d shows the condition of the lancet together with the retracted protective cap (5) and sealing member (6) after priming.
Fig. 3e and 3f show the contact of the lancet (2) after activation. In this state, the spring contact (7) engages in a recess (13a) of the lancet holder (13). In this case, the bent tip (15a) of the spring contact (7) comes into contact with the lancet (2). Fig. 4a to 4c show the case where the lancet (2) is used as a level controller or as a counter electrode.
For level measurement, fig. 4a shows that the potential that changes between the lancet (2) and the electrode (3) is measured. The injection of the test chamber (8) can be detected by measuring the current when a direct or alternating voltage is used. The lancet can additionally be used as a measuring electrode. This is shown in fig. 4 b. The lancet (2) is also shown connected to the contact (7) after retraction, and a direct or alternating voltage (14) is applied between the working electrode (3) in the chamber and the lancet (2). In this way, the current change due to the reaction of the sample liquid with the detection reagent on the electrode (3) is measured. In which case only one electrode is required in the test chamber. Fig. 4c shows two additional features of the lancet (2), namely the combination of the level measurement and the counter electrode. In this case two separate circuits are provided on the lancet (2) and the electrode (3).
Fig. 5a shows a front view of the analytical aid (1), wherein the protective cap (5) is arranged in the opening (9) together with the lancet (2). Figure 5b shows a side view of the test chamber. In this figure, the extension of the lancet (2) in the testing chamber (8) can be seen.
Figure 5c shows an oval shaped test chamber. The test chamber extends over the electrodes up to the protective cover (5). Fig. 5d shows an alternative test chamber, in which the oval chamber is delimited by a boundary on the side of the electrode facing, so that a smaller chamber volume is achieved.
Fig. 6 shows a system in which the protective cover (5) additionally serves as a closure mechanism for the second opening (10). In this case this second opening is a vent hole in the membrane cover. In the system, electrodes (3) are visible, which extend into the chamber (8), and a protective cover (5) is also visible, which protective cover (5) seals the chamber and the lancet tip (12) and encloses the rest of the lancet (3). A lancet holder (13) is provided at the proximal end of the lancet (3). A gripping means (11) is provided in front of the lancet holder towards the distal end of the lancet (3).

Claims (12)

1. An analysis assisting mechanism comprising
I) A lancing device comprising
A lancet needle with a tip and a protective cap, which completely surrounds the lancet needle at least in the region of the tip,
wherein the lancet needle is movable relative to the protective cap and the lancet interacts with the protective cap in such a way that the lancet pulls the protective cap back together when the lancet is pulled back, and
II) a test element with a chamber containing a reagent system, wherein the chamber has a first opening which is closed by a protective cover.
2. The analytical aid of claim 1, wherein the material of the protective cover is an elastomer.
3. An analytical aid according to claim 1 or 2 wherein the protective shield aseptically encloses the needle tip.
4. Analytical aid according to claim 1 or 2, wherein the analytical aid has means for transporting the sample liquid.
5. Analytical aid according to claim 4, wherein the means for transporting the sample liquid is a capillary gap, a capillary channel or a wick made of an absorbent material or a tab made of an absorbent material.
6. An analytical aid according to claim 1 or 2 wherein the aid has a second opening sealed by a seal movable relative to the lancet and relative to the aid.
7. The analytical aid of claim 6 wherein the protective cover seals the first and second openings.
8. An analytical aid according to claim 1 or 2 wherein gripping means or surface formations are provided on the lancet which pull back the protective cover penetrated by the lancet together when the lancet is pulled back.
9. The analytical aid mechanism according to claim 8 wherein upon retraction of the lancet, the retracted protective cover retracts the seal movable relative to the lancet together and opens the vent.
10. Analytical aid according to claim 1 or 2, wherein the lancet has means for sample liquid level measurement and/or for use as a counter electrode.
11. Method for producing an analytical aid, comprising the following steps:
providing a lancet in which the tip of the lancet needle is located in a protective cover;
a gripping device is arranged on the lancet, and when the lancet is pulled back, the gripping device pulls back the protective cover together;
providing a test element having a chamber, containing a reagent system and an opening in the chamber, and
sterilizing the lancet;
the lancet is inserted into the chamber such that the protective cover closes the opening of the chamber.
12. An analysis system having an analysis assisting mechanism according to any one of claims 1 to 10.
HK09103371.4A2005-10-202006-10-14Analytical contrivance with sterile protection for the lancet and test chamberHK1125019B (en)

Applications Claiming Priority (3)

Application NumberPriority DateFiling DateTitle
EP05022830.32005-10-20
EP05022830AEP1776925A1 (en)2005-10-202005-10-20Analyzing means with lancet and test element
PCT/EP2006/009944WO2007045411A1 (en)2005-10-202006-10-14Analytical contrivance with sterile protection for the lancet and test chamber

Publications (2)

Publication NumberPublication Date
HK1125019A1 HK1125019A1 (en)2009-07-31
HK1125019Btrue HK1125019B (en)2011-07-15

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