A fully implantable sensor and method of making the same

Abstract

The application provides a fully implanted sensor and a preparation method thereof, relates to the field of electrochemical detection, and the fully implanted sensor is prepared by arranging a conductive contact as a lead wire on a shell, arranging an independent conductive layer on the conductive contact, and arranging electrodes on the conductive layer, and the electrodes are prepared without an insulating layer, the preparation method is simple, and the cost is low. The conductive layer is insulated and one-to-many by cutting a conductive coating, a plurality of independent conductive layers are divided from one conductive coating, and the conductive layers are used for preparing detection electrodes to meet test requirements. Each functional layer can be realized through printing, dip coating and other processes, and steps such as a complex mask, photoresist and photoresist development are not needed, so that the operation is simple, and large-scale preparation can be realized.

Description

Technical Field

[0001] This application relates to the field of electrochemical detection, and in particular to a fully implantable sensor and its preparation method. Background Technology

[0002] Blood glucose monitoring is an important part of the treatment and management of diabetes. It not only helps to assess the degree of glucose metabolism disorder in diabetic patients, develop reasonable blood glucose lowering plans, and reflect the blood glucose lowering effect, but also helps to prevent hypoglycemia.

[0003] In June 2018, the U.S. FDA approved the Eversense implantable continuous glucose monitoring system developed by Senseonics. This system utilizes a fluorescent polymer that interacts with glucose, generating a fluorescent signal under a specific wavelength of light. This signal is then converted into an electrical signal by a micro-photosensitive element integrated within the chip, thereby monitoring glucose concentration. However, the fluorescence generated by the reaction of the fluorescent substance with glucose in tissue fluid is collected by a receiver through the photosensitive element of the internal chip, raising concerns about biological and individual variability. Furthermore, the selectivity of the synthesized fluorescent polymer for glucose in tissue fluid is not as high as the specificity of glucose oxidase for glucose, making it difficult to eliminate background interference when glucose concentration is low.

[0004] Based on this, a fully implantable blood glucose monitoring system based on electrochemical testing of highly specific oxidoreductases has been developed. The sensor is one of the core components of the fully implantable blood glucose monitoring system. However, in the existing technology, the preparation of the sensor is technically difficult, mass production is difficult, the cost is high, and the manufacturing method is complex. Summary of the Invention

[0005] The purpose of this application is to provide a fully implantable sensor that addresses the problems of high technical difficulty, mass production difficulty, high cost, and complex manufacturing methods in the fabrication of existing sensors.

[0006] To achieve the above objectives, this application provides a fully implantable sensor, comprising:

[0007] A housing, wherein a circuit board is disposed within the housing;

[0008] At least two conductive contacts are disposed on the housing and electrically connected to the circuit board;

[0009] The detection electrodes are each independently covered on the at least two conductive contacts.

[0010] Preferably, the detection electrode comprises:

[0011] The counter electrode includes a conductive layer covering the conductive contact and an electrode layer disposed on the conductive layer;

[0012] The working electrode includes a conductive layer covering the conductive contact and an enzyme layer disposed on the conductive layer.

[0013] Preferably, the conductive contacts are at least three, and the detection electrode further includes:

[0014] A reference electrode, the reference electrode comprising a conductive layer covering the conductive contact.

[0015] This application also provides a method for fabricating a fully implantable sensor, comprising:

[0016] At least two conductive contacts are provided on the housing;

[0017] At least two conductive layers are provided, each independently covering the at least two conductive contacts;

[0018] An electrode layer is disposed on any of the conductive layers to serve as a counter electrode;

[0019] An enzyme layer is disposed on at least one of the conductive layers outside the counter electrode to serve as a working electrode.

[0020] Preferably, the provision of at least two conductive layers, each independently covering the at least two conductive contacts, includes:

[0021] A conductive coating is prepared on the housing, the conductive coating covering the at least two conductive contacts;

[0022] The conductive coating is cut into at least two independent portions, such that the conductive coating in each portion covers one of the conductive contacts.

[0023] Preferably, the at least two conductive contacts are disposed on the side wall of the housing, which may be close to one end of the housing or close to both ends of the housing; the at least two conductive contacts are arranged along the length of the housing.

[0024] Preferably, there are three conductive contacts and three conductive layers, and the electrode layer is disposed on the conductive layer near the end of the housing or on the conductive layer near the center of the housing as a counter electrode;

[0025] The enzyme layer is disposed on the conductive layer opposite to the counter electrode spacing, serving as the working electrode;

[0026] The conductive layer between the counter electrode and the working electrode serves as a reference electrode.

[0027] Preferably, the method for preparing the conductive coating is selected from any one of sputtering, vapor deposition, chemical vapor deposition, electroplating, dip coating, screen printing, and spraying.

[0028] The conductive coating has a thickness of 1~1000nm and a width of 5~10mm; the conductive coating is selected from any one of silver, platinum, gold, palladium, and their oxides.

[0029] Preferably, the cutting method for the conductive coating is selected from any one of laser cutting, roll cutting, and plasma etching;

[0030] The cutting depth of the conductive coating is greater than or equal to the thickness of the conductive coating, but not greater than the thickness of the shell, and the cutting width is 1~100nm.

[0031] Preferably, the electrode layer comprises an Ag / AgCl layer; the thickness of the Ag / AgCl layer is 1~1000 nm; the preparation method of the electrode layer is selected from any one of dip coating, screen printing, sputtering, vapor deposition, chemical vapor deposition, electroplating, and spraying.

[0032] Preferably, the enzyme layer is prepared by any one of screen printing, sputtering, vapor deposition, chemical vapor deposition, electroplating, dip coating, and spraying; the enzyme layer is selected from any one or more of glucose oxidase, uricase oxidase, lactate dehydrogenase, glucose dehydrogenase, peroxidase, β-hydroxybutyrate dehydrogenase, and sarcosine oxidase.

[0033] Preferably, the preparation method further includes:

[0034] An outer film is prepared to cover the entire conductive layer region; the covering method is selected from any one of sputtering, evaporation, chemical vapor deposition, electroplating, spraying, dip coating, and screen printing.

[0035] The outer membrane material is selected from any one or more of polyamide, polyurethane, polyvinyl alcohol, polysulfate, and cellulose acetate;

[0036] The permeability of the outer membrane is 10% to 70%.

[0037] Compared with the prior art, the beneficial effects of this application include:

[0038] The fully implantable sensor and its fabrication method provided in this application use conductive contacts on the housing as wires, independent conductive layers on the conductive contacts, and electrodes on the conductive layers. No insulating layer is required between the electrodes. The fabrication method is simple and low in cost.

[0039] This conductive layer achieves insulation and multi-functionality by cutting a conductive coating. A single conductive coating is divided into multiple independent conductive layers for fabricating detection electrodes, thus meeting the testing needs of various substances. Each functional layer can be fabricated through processes such as printing and dip coating, eliminating the need for complex steps like photomasks, photoresists, and photolithography development. The process is simple, low-cost, and allows for large-scale fabrication. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0041] Figure 1 This is a schematic diagram showing the installation of conductive contacts on the housing.

[0042] Figure 2 This is a schematic diagram showing the conductive coating applied to the conductive contact.

[0043] Figure 3 This is a schematic diagram of the conductive coating after cutting according to an embodiment;

[0044] Figure 4 This is a schematic diagram showing the preparation of an Ag / AgCl layer in one of the conductive layers;

[0045] Figure 5 This is a schematic diagram showing the enzyme layer after preparation on another conductive layer.

[0046] Figure 6 This is a schematic diagram after enzyme cross-linking;

[0047] Figure 7 This is a schematic diagram after the outer membrane has been prepared;

[0048] Figure 8 This is a schematic diagram of the conductive coating after cutting, according to another embodiment;

[0049] Figure 9 for Figure 8 A schematic diagram showing the unfolded side view after cutting the conductive coating;

[0050] Figure 10 This is a schematic diagram of the fabrication process of the fully implantable sensor in this application;

[0051] Figure 11 This is a schematic diagram of the fabrication process of the conductive layer;

[0052] Figure 12 This is a quarter-section view of the fully implantable sensor of this application;

[0053] Figure 13 This is a schematic diagram of the conductive element of the fully implantable sensor in this application.

[0054] Figure label:

[0055] 100 - Fully implantable sensor; 10 - Housing; 12 - Conductive contact; 20 - Detection electrode; 22 - Counter electrode; 221 - Electrode layer; 24 - Working electrode; 241 - Enzyme layer; 26 - Reference electrode; 30 - Conductive coating; 32 - Conductive layer; 40 - Circuit board; 50 - Conductive element; 52 - Base; 54 - Elastic bond; 56 - Conductive contact. Detailed Implementation

[0056] As used in this article:

[0057] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0058] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0059] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0060] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0061] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0062] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0063] This application provides a method for fabricating a fully implantable sensor, which includes a housing, a detection circuit, and detection electrodes. This fully implantable sensor can be used to measure any one of the following indicators: blood glucose, uric acid, lactic acid, blood ketones, or creatinine, or any combination of multiple indicators therein. Please refer to... Figure 10 The preparation method includes:

[0064] S100: At least two conductive contacts are provided on the housing.

[0065] Specifically, the shell, as the implant material, can be made of materials such as polyimide, polyester, polyurethane, and polyethylene. The shell provides a substrate for the electrochemical sensor and fixes and protects the circuit board. After implantation, the electrochemical sensor connects to the circuit board inside the shell via conductive contacts, preventing direct contact between the circuit board and tissue fluid and improving the lifespan of the fully implantable sensor. The shell can be rectangular, cubic, or cylindrical, or any other shape. A hollow cylinder is preferred for better biocompatibility and to prevent square or other sharp-angled shells from damaging internal tissues or causing severe allogeneic reactions after implantation. The preferred shell dimensions are an outer diameter of 5mm, an inner diameter of 3mm, and a height of 20mm. The space between the outer and inner diameters can be solid or form a space to accommodate the circuit board. It is understood that the shell dimensions can be set according to actual use and are not limited to these dimensions.

[0066] Conductive contacts are embedded in the housing. These contacts can penetrate the inner and outer surfaces of the housing, or only the outer surface, to connect the circuit board and the detection electrode inside and outside the housing. The conductive contacts can be made of conductive plastics, conductive rubber, metals, graphite, or other conductive materials. The number of conductive contacts can be two, three, four, or more. For electrochemical detection, the detection electrode should have at least one counter electrode and one working electrode, forming a conventional two-electrode system. Three conductive contacts can also be used, forming a three-electrode system, including a counter electrode, a working electrode, and a reference electrode. Multiple working electrodes can be used, allowing for the simultaneous detection of multiple indicators, thus increasing the number of conductive contacts accordingly.

[0067] Please see Figure 1 , Figure 1 This is a schematic diagram of an embodiment in which conductive contacts 12 are provided in the housing 10. In this embodiment, there are three conductive contacts 12, which are disposed on the side wall of the housing 10 and near one end of the housing 10, and the three conductive contacts 12 are arranged vertically. It can be understood that in other embodiments, the conductive contacts 12 may also be disposed on the end face of the housing 10, or in the middle of the side wall of the housing 10, or may be arranged horizontally.

[0068] In a preferred embodiment, please refer to Figure 1 The at least two conductive contacts 12 are disposed on the side wall of the housing 10 and close to one end of the housing 10; the at least two conductive contacts 12 are arranged along the length of the housing 10. This arrangement of the conductive contacts 12 facilitates the preparation of subsequent functional layers using a dip-coating method, which is simpler and less costly.

[0069] S200: Provide at least two conductive layers, each independently covering the at least two conductive contacts.

[0070] Specifically, the conductive layer can be any of silver, platinum, gold, palladium, or their oxides. The conductive layer independently covering the conductive contact means that the conductive layers are not spatially connected, thus providing spatial insulation. This eliminates the need for separate insulating layers between the conductive layers, simplifying the fabrication process. The conductive layer can be fabricated using processes such as sputtering, evaporation, chemical vapor deposition, electroplating, dip coating, and screen printing.

[0071] In a preferred embodiment, please refer to Figure 11 Step S200: The provision of at least two conductive layers, each independently covering the at least two conductive contacts, includes:

[0072] S210: A conductive coating is prepared on the housing, the conductive coating covering the at least two conductive contacts.

[0073] For details, please refer to Figure 2 Conductive coating 30 covers Figure 1 All conductive contacts 12 shown can be coated with conductive coating 30, which can be any of the conductive materials such as silver, platinum, gold, palladium and their oxides. The conductive coating 30 can be prepared by processes such as sputtering, evaporation, chemical vapor deposition, electroplating, dip coating, screen printing, spraying, etc. By preparing conductive coating 30 to cover all conductive contacts 12, only one preparation of conductive coating is required, which can simplify the preparation process.

[0074] Understandable Figure 2 The conductive coating 30 shown covers the conductive contact 12 around the housing 10. In other embodiments, the conductive coating 30 may only cover the conductive contact 12 without surrounding the housing 10. For example, the conductive coating 30 may be prepared only on the surface of the half of the housing 10 where the conductive contact 12 is provided.

[0075] The thickness of the conductive coating 30 is 1~1000 nm, for example, it can be (1, 3, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900 or 1000) nm. The width of the conductive coating 30 is 5~20 mm, for example, it can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or 20 mm, and the width of the conductive coating 30 is equivalent to its height in the length direction of the housing 10.

[0076] S220: The conductive coating is cut into at least two independent parts, such that the conductive coating in each part covers one of the conductive contacts.

[0077] The conductive coating can be cut using any of the following methods: laser cutting, roll cutting, or plasma etching. By cutting the conductive coating, it is spatially divided into independent parts. The cutting depth of the conductive coating should ensure that there is no connection between the independent conductive coating parts, thereby forming spatial isolation and insulation. Cutting allows multiple conductive layers to be obtained by preparing the conductive coating only once, simplifying the preparation method.

[0078] The cutting depth of the conductive coating is greater than or equal to the thickness of the conductive coating, but not greater than the thickness of the shell. The cutting depth can be, for example, 1~1000 nm, specifically (1, 3, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000) nm. Preferably, the cutting depth of the conductive coating is the same as the thickness of the conductive coating. The cutting width is 1~100 nm, specifically (1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100) nm. The cutting width refers to the width of the cutting grooves in the conductive coating, that is, the distance between each individual conductive coating layer.

[0079] In one embodiment, please refer to Figure 2 and Figure 3 The conductive coating 30 is cut in a circumferential manner along the housing 10. For the case of three conductive contacts, two cuts are required to completely separate the conductive coating 30 and form conductive layers 32. Each conductive layer 32 is independent of the others and covers one conductive contact. For the case of two conductive contacts, only one cut is required.

[0080] In another embodiment, please refer to Figure 8 and Figure 9 For three or more conductive contacts, the conductive coating can be cut using a spiral cut. A spiral cut only requires one cut to completely separate the conductive coating.

[0081] S300: An electrode layer is disposed on any of the conductive layers as a counter electrode.

[0082] The electrode layer can be disposed on any conductive layer, and the electrode layer can be an Ag / AgCl layer; the thickness of the Ag / AgCl layer is 1~1000nm; the electrode layer can be prepared by any one of dip coating, screen printing, sputtering, evaporation, chemical vapor deposition, electroplating, and spraying.

[0083] The counter electrode and the working electrode form a circuit to ensure that the current flows smoothly on the working electrode, so as to ensure that the reaction under study occurs on the working electrode.

[0084] For details, please refer to Figure 3 and Figure 6An electrode layer 221 is disposed on the uppermost conductive layer 32 near the center of the housing 10 to form a counter electrode 22. In other embodiments, the electrode layer 221 can also be disposed on the middle conductive layer 32 or the lowermost conductive layer 32 near the end of the housing 10. For a three-electrode system, preferably, the counter electrode is disposed on the uppermost conductive layer 32 near the center or end of the housing 10, or the lowermost conductive layer 32 near the end of the housing 10. Therefore, when preparing the electrode layer 221, only one side of the conductive layer 32 needs to be blocked, making the preparation method simpler.

[0085] S400: An enzyme layer is disposed on at least one of the conductive layers outside the counter electrode to serve as a working electrode.

[0086] The working electrode and the counter electrode do not overlap. One enzyme layer corresponds to one working electrode. For example, if only one indicator needs to be detected, one enzyme layer is set on one conductive layer to obtain one working electrode. If two indicators need to be detected, one enzyme layer is set on each of the two conductive layers to obtain two working electrodes.

[0087] The enzyme layer is prepared by any one of screen printing, sputtering, vapor deposition, chemical vapor deposition, electroplating, dip coating, and spraying; the enzyme layer is selected from any one or more of glucose oxidase, uricase oxidase, lactate dehydrogenase, glucose dehydrogenase, peroxidase, β-hydroxybutyrate dehydrogenase, and sarcosine oxidase.

[0088] Preferably, please refer to Figures 3 to 6 The enzyme layer 241 is disposed on the conductive layer 32, which is spaced apart from the counter electrode 22, and serves as the working electrode 24. Figure 5 The enzyme layer 241 shown can be prepared by dip coating, a simple and controllable process. In other embodiments, the enzyme layer 241 can also be disposed in the intermediate conductive layer 32.

[0089] The conductive layer 32 between the counter electrode 22 and the working electrode 24 serves as the reference electrode 26.

[0090] Furthermore, after preparing enzyme layer 241, the implant material can be placed in a sealed cavity filled with cross-linking agent gas for cross-linking. Optionally, the cross-linking agent can be glutaraldehyde solution, perfluorosulfonic acid resin solution, etc.

[0091] Furthermore, the preparation method further includes:

[0092] For the fabrication of an outer film covering the entire conductive layer area, please refer to [link to documentation]. Figure 7 This includes insulating gaps between conductive layers; the outer film coating method can be any one of sputtering, vapor deposition, chemical vapor deposition, electroplating, spraying, dip coating, or screen printing.

[0093] The outer membrane material is selected from one or more of polyamide, polyurethane, polyvinyl alcohol, polysulfate, and cellulose acetate.

[0094] The permeability of the outer membrane is 10% to 70%, for example, it can be 10%, 20%, 30%, 40%, 50%, 60% or 70%. The permeability of the outer membrane in each conductive layer region can be the same or different, mainly depending on the indicators to be detected.

[0095] Because the detection ranges of in vivo test substances vary—for example, blood glucose ranges from 2.2 to 27.8 mmol / L, blood ketone ranges from 0.1 to 8.0 mmol / L, and uric acid ranges from 0.179 to 1.190 mmol / L—the preparation of the outer membrane can be adjusted according to the concentration of the test substance to provide a suitable permeability for long-term detection of different substances in vivo. For example, the outer membrane permeability might be 10% for blood glucose testing, 50% for blood ketone testing, and 70% for uric acid testing. When preparing the outer membrane for different test substances, the outer membrane composition can be adjusted, such as by preparing outer membrane solutions of different concentrations or polymer types, and then coating different areas with the outer membrane using spraying, dotting, or spin coating methods. Alternatively, the same outer membrane composition can be used with different operating steps to achieve different permeability levels, such as by increasing or decreasing the number of coating operations.

[0096] Through the above steps, the fully implantable sensor electrode area is prepared. The test circuit board is then installed into the hollow cavity of the implant material. The shell is made of two or more parts. After sealing and sterilizing the shell, a single fully implantable sensor can be obtained. Alternatively, the shell can be integrally formed, and the fully implantable sensor electrode area can be prepared on the shell.

[0097] A fully implantable sensor is obtained according to the above-described method for fabricating the sensor. Please refer to [link / reference]. Figure 1 and Figure 7 Its structure includes: a housing 10, in which a circuit board is disposed; at least two conductive contacts 12, disposed on the housing 10 and electrically connected to the circuit board; and detection electrodes 20, each independently covering the at least two conductive contacts 12.

[0098] In Embodiment 1, the detection electrode 20 includes: a counter electrode 22, which includes a conductive layer 32 covering the conductive contact 12 and an electrode layer 221 disposed on the conductive layer 32; and a working electrode 24, which includes a conductive layer 32 covering the conductive contact 12 and an enzyme layer 241 disposed on the conductive layer 32.

[0099] The detection electrode 20 consists only of the counter electrode 22 and the working electrode 24, and its structure is simpler, easier to prepare, and lower in cost.

[0100] In Embodiment 2, there are at least three conductive contacts 12, and the detection electrode 20 further includes a reference electrode 26, which includes a conductive layer 32 covering the conductive contacts 12.

[0101] In Embodiment 3, the conductive contact 12 is at least four, and the detection electrode also includes a second working electrode. By preparing an enzyme layer different from the first working electrode on the second working electrode, and coating the enzyme layer with an outer membrane with a different permeability than the first working electrode, the simultaneous monitoring of two substances in the body can be achieved.

[0102] The reference electrode 26 can eliminate the large error in electrode potential caused by polarization current, making the detection structure more accurate.

[0103] When performing multi-index testing, since the two working electrode areas are independent and the test paths are separate, different test voltages and corresponding test times can be set. Through algorithm optimization, mutual interference between the two substances during testing is avoided.

[0104] The electrical connection between the detection electrode 20 and the circuit board 40 can be achieved through... Figure 12 and Figure 13 The conductive element 50 shown is implemented. The conductive element 50 includes: a base 52, which is fixed on the circuit board 40; a spring key 54, which is disposed within the base 52; and a conductive contact 56, which is disposed on the spring key 54.

[0105] The base 52, the elastic key 54, and the conductive contact 56 all have conductive properties, and the elastic key 54 can be a spring. After the conductive element 50 is installed into the housing 10 along with the circuit board 40, the conductive element 50 is squeezed by the housing 10 and comes into contact with the conductive contact 12, realizing electrical conduction between the circuit board 40 and the detection electrode 20.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0107] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A fully implantable sensor, characterized in that, include: Housing (10), wherein a circuit board (40) is disposed inside the housing; At least two conductive contacts (12) are disposed on the housing (10) and electrically connected to the circuit board (40). The conductive contacts (12) are embedded in the housing (10) and penetrate the inner and outer surfaces of the housing (10) or only penetrate the outer surface. The detection electrodes (20) are each independently covered on the at least two conductive contacts (12); The detection electrode includes: The counter electrode (22) includes a conductive layer (32) covering the conductive contact (12) and an electrode layer (221) disposed on the conductive layer. The working electrode (24) includes a conductive layer (32) covering the conductive contact (12) and an enzyme layer (241) disposed on the conductive layer.

2. The fully implantable sensor according to claim 1, characterized in that, The conductive contacts (12) are at least three, and the detection electrode (20) further includes: The reference electrode (26) includes a conductive layer (32) covering the conductive contact (12).

3. A method for fabricating a fully implantable sensor, characterized in that, include: At least two conductive contacts are provided on the housing, the conductive contacts are embedded in the housing, and the conductive contacts penetrate the inner and outer surfaces of the housing or only penetrate the outer surface; A conductive coating is prepared on the housing, the conductive coating covering the at least two conductive contacts; The conductive coating is cut into at least two independent parts, such that the conductive coating in each part covers one of the conductive contacts, to obtain at least two conductive layers. An electrode layer is disposed on any of the conductive layers to serve as a counter electrode; An enzyme layer is disposed on at least one of the conductive layers outside the counter electrode to serve as a working electrode.

4. The preparation method according to claim 3, characterized in that, The at least two conductive contacts are disposed on the side wall of the housing; the at least two conductive contacts are arranged along the length of the housing.

5. The preparation method according to claim 3 or 4, characterized in that, There are three conductive contacts and three conductive layers. The electrode layer is provided on the conductive layer near the end of the housing or on the conductive layer near the center of the housing as a counter electrode. The enzyme layer is disposed on the conductive layer opposite to the counter electrode spacing, serving as the working electrode; The conductive layer between the counter electrode and the working electrode serves as a reference electrode.

6. The preparation method according to claim 3, characterized in that, The method for preparing the conductive coating is selected from any one of sputtering, vapor deposition, chemical vapor deposition, electroplating, dip coating, screen printing, and spraying. The conductive coating has a thickness of 1~1000nm and a width of 5~10mm; the conductive coating is selected from any one of silver, platinum, gold, palladium, and their oxides.

7. The preparation method according to claim 3, characterized in that, The cutting method for the conductive coating is selected from any one of laser cutting, roll cutting, and plasma etching; The cutting depth of the conductive coating is greater than or equal to the thickness of the conductive coating, but not greater than the thickness of the shell, and the cutting width is 1~100nm.

8. The preparation method according to claim 3, characterized in that, The electrode layer includes an Ag / AgCl layer; the thickness of the Ag / AgCl layer is 1~1000 nm; the preparation method of the electrode layer is selected from any one of dip coating, screen printing, sputtering, vapor deposition, chemical vapor deposition, electroplating, and spraying.

9. The preparation method according to claim 3, characterized in that, The enzyme layer is prepared by any one of screen printing, sputtering, vapor deposition, chemical vapor deposition, electroplating, dip coating, and spraying; the enzyme layer is selected from any one or more of glucose oxidase, urate oxidase, lactate dehydrogenase, glucose dehydrogenase, peroxidase, β-hydroxybutyrate dehydrogenase, and sarcosine oxidase.

10. The preparation method according to claim 3, characterized in that, The preparation method further includes: An outer film is prepared to cover the entire conductive layer area; the covering method is selected from any one of sputtering, evaporation, chemical vapor deposition, electroplating, spraying, dip coating, and screen printing; The outer membrane material is selected from any one or more of polyamide, polyurethane, polyvinyl alcohol, polysulfate, and cellulose acetate; The permeability of the outer membrane is 10% to 70%.

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