阅读说明：本技术 一种三电极皮下植入式葡萄糖传感器及其制作方法 (Three-electrode subcutaneous implanted glucose sensor and manufacturing method thereof ) 是由 章锋 祝军 孙华春 徐恒 顾华良 于 2020-07-24 设计创作，主要内容包括：一种三电极皮下植入式葡萄糖传感器及其制作方法,本发明的传感器采用工作电极、参考电极和辅助电极的三电极形式,测试的微电流从工作电极和辅助电极通过,参考电极基本没有电流通过,从而延长参考电极的使用寿命；通过对传感器电极制作工艺的改进,使得工艺变的简单、质量可控,并且保持了工作电极葡萄糖氧化酶的稳定性,确保传感器测试数据准确；此外,取消了牛血清白蛋白等载体,采用戊二醛和硅烷双功能偶联的方式保证葡萄糖氧化酶的活性和稳定性,降低了对人体的安全隐患,减轻了人体的排异反应；通过发射器和传感器可拆装的卡合连接方式,使得传感器和发射器能够方便分离,实现更换传感器后发射器还能够重复使用,降低了用户的使用成本。(The invention relates to a three-electrode subcutaneous implanted glucose sensor and a manufacturing method thereof, wherein the sensor adopts a three-electrode form of a working electrode, a reference electrode and an auxiliary electrode, a tested micro-current passes through the working electrode and the auxiliary electrode, and the reference electrode basically has no current, so that the service life of the reference electrode is prolonged; by improving the manufacturing process of the sensor electrode, the process is simple, the quality is controllable, the stability of the working electrode glucose oxidase is kept, and the accuracy of the test data of the sensor is ensured; in addition, carriers such as bovine serum albumin and the like are cancelled, the activity and the stability of the glucose oxidase are ensured by adopting a mode of bifunctional coupling of glutaraldehyde and silane, the potential safety hazard to a human body is reduced, and the rejection reaction of the human body is lightened; through the dismantled and assembled block connected mode of transmitter and sensor for sensor and transmitter can conveniently separate, realize changing behind the sensor transmitter and can also used repeatedly, have reduced user's use cost.)

1. A three-electrode subcutaneously implantable glucose sensor, comprising: the device comprises a needle-shaped working electrode (1), a reference electrode (2) and an auxiliary electrode (3), wherein the working electrode (1), the reference electrode (2) and the auxiliary electrode (3) are fixed on a sensor seat (4);

the working electrode (1) comprises a first conductive substrate (11), a first metal transition layer (12), a first noble metal layer (13), an inner coupling layer (14), an immobilized enzyme layer (15), an outer coupling layer (16) and a first polymer film layer (17) from inside to outside;

the reference electrode (2) comprises a second conductive substrate (21), a second metal transition layer (22), a silver \ silver chloride layer (23) and a second polymer film layer (24) from inside to outside;

the auxiliary electrode (3) comprises a third conductive substrate (31), a third metal transition layer (32), a second noble metal layer (33), a coupling layer (34) and a third high molecular film layer (35) from inside to outside.

2. The three-electrode subcutaneously implantable glucose sensor of claim 1, wherein: the sensor seat (4) comprises a plastic base body (41), three metal connection points (42) which are arranged in a triangular mode are located in the middle of the plastic base body (41), a mounting hole is formed in the middle of each metal connection point (42), and the needle tail ends of the working electrode (1), the reference electrode (2) and the auxiliary electrode (3) penetrate through the mounting holes and then are connected and conducted with the metal connection points (42).

3. The three-electrode subcutaneously implantable glucose sensor of claim 2, wherein: the three metal connecting points (42) are arranged in a regular triangle, and the side length of the regular triangle is 3-6 mm.

4. A three-electrode subcutaneously implantable glucose sensor according to claim 3, wherein: the working electrode (1), the reference electrode (2) and the auxiliary electrode (3) are all arranged perpendicular to the plastic substrate (41).

5. The three-electrode subcutaneously implantable glucose sensor of claim 2, wherein: the sensor seat (4) further comprises at least three metal contacts (43) positioned on the plastic base body (41), the metal contacts (43) are respectively communicated with the metal connecting points (42), and the plastic base body (41) is provided with a clamping mechanism (411) connected with the emitter.

6. The three-electrode subcutaneously implantable glucose sensor of claim 5, wherein: an operational amplifier is installed in the transmitter, the reference electrode (2) is electrically connected with the reverse input end of the operational amplifier through the metal connecting point (42) and the metal contact (43), and the auxiliary electrode (3) is electrically connected with the output end of the operational amplifier through the metal connecting point (42) and the metal contact (43).

7. The three-electrode subcutaneously implantable glucose sensor of claim 1, wherein: the first conductive substrate (11) is made of stainless steel, the first metal transition layer (12) is made of gold, the first precious metal layer (13) is made of platinum, the inner coupling layer (14) and the outer coupling layer (16) are made of silane, the immobilized enzyme layer (15) is made of glucose oxidase, and the first polymer film layer (17) is made of polyurethane and/or polyethylene glycol.

8. The three-electrode subcutaneously implantable glucose sensor of claim 1, wherein: the second conductive substrate (21) is made of stainless steel, the second metal transition layer (22) is made of silver, and the second polymer film layer (24) is made of polyurethane and/or polyethylene glycol.

9. The three-electrode subcutaneously implantable glucose sensor of claim 1, wherein: the third conductive substrate (31) is made of stainless steel, the third metal transition layer (32) is made of gold, the second noble metal layer (33) is made of platinum, the coupling layer (34) is made of silane, and the third high-molecular film layer (35) is made of polyurethane and/or polyethylene glycol.

10. A manufacturing method of a three-electrode subcutaneous implantation type glucose sensor is characterized by comprising the following steps: the sensor comprises a needle-shaped working electrode (1), a reference electrode (2) and an auxiliary electrode (3), wherein the working electrode (1), the reference electrode (2) and the auxiliary electrode (3) are fixed on a sensor seat (4);

the working electrode (1) comprises a first conductive substrate (11), a first metal transition layer (12), a first noble metal layer (13), an inner coupling layer (14), an immobilized enzyme layer (15), an outer coupling layer (16) and a first high polymer film layer (17) from inside to outside, wherein the first conductive substrate (11) is made of stainless steel, the first metal transition layer (12) is gold, the first noble metal layer (13) is platinum, the inner coupling layer (14) and the outer coupling layer (16) are made of silane, the immobilized enzyme layer (15) is glucose oxidase, and the first high polymer film layer (17) is made of polyurethane and/or polyethylene glycol;

the reference electrode (2) comprises a second conductive substrate (21), a second metal transition layer (22), a silver \ silver chloride layer (23) and a second polymer film layer (24) from inside to outside, wherein the second conductive substrate (21) is made of stainless steel, the second metal transition layer (22) is made of silver, and the second polymer film layer (24) is made of polyurethane and/or polyethylene glycol;

the auxiliary electrode (3) comprises a third conductive substrate (31), a third metal transition layer (32), a second noble metal layer (33), a coupling layer (34) and a third high molecular film layer (35) from inside to outside, wherein the third conductive substrate (31) is made of stainless steel, the third metal transition layer (32) is made of gold, the second noble metal layer (33) is made of platinum, the coupling layer (34) is made of silane, and the third high molecular film layer (35) is made of polyurethane and/or polyethylene glycol;

the first metal transition layer (12) of the working electrode (1) is covered on the outer layer of the first conductive substrate (11) by adopting an electrochemical deposition method; the first noble metal layer (13) is covered on the outer layer of the first metal transition layer (12) by adopting a cation etching method or an electrochemical deposition method; the inner coupling layer (14) is covered on the outer layer of the first noble metal layer (13) in a dipping or coating mode; the immobilized enzyme layer (15) is attached to the outer layer of the inner coupling layer (14) by an enzyme solution in a dipping or coating mode; the outer coupling layer (16) is covered on the outer layer of the immobilized enzyme layer (15) in a dipping or coating mode; the first polymer film layer (17) is covered on the outer layer of the outer coupling layer (16) in a dipping or coating mode.

11. The method for manufacturing a three-electrode subcutaneously implantable glucose sensor of claim 10, wherein: the second metal transition layer (22) of the reference electrode (2) is covered on the outer layer of the second conductive substrate (21) by adopting an electrochemical deposition method; the silver/silver chloride layer (23) is formed by chlorination of the second metal transition layer (22); the second polymer film layer (24) is covered on the outer layer of the silver/silver chloride layer (23) in a dipping or coating mode.

12. The method for manufacturing a three-electrode subcutaneously implantable glucose sensor of claim 10, wherein: the third metal transition layer (32) of the auxiliary electrode (3) is covered on the outer layer of the third conductive substrate (31) by adopting an electrochemical deposition method; the second noble metal layer (33) is covered on the outer layer of the third metal transition layer (32) by adopting a cation etching method or an electrochemical deposition method; the coupling layer (34) is covered on the outer layer of the second noble metal layer (33) in a dipping or coating mode; the third high molecular film layer (35) is covered on the outer layer of the coupling layer (34) in a dipping or coating mode.

13. The method for manufacturing a three-electrode subcutaneously implantable glucose sensor of claim 10, wherein: the solute of the enzyme solution is glucose oxidase, the solution is phosphoric acid buffer solution, and the concentration of the glucose oxidase is 0.02 g/ml-0.2 g/ml.

14. The method for manufacturing a three-electrode subcutaneously implantable glucose sensor of claim 13, wherein: the glucose oxidase is crosslinked and solidified through glutaraldehyde.

15. The method of claim 14, wherein the method comprises: the cross-linking temperature of the glucose oxidase and the glutaraldehyde is 25-35 ℃, and the single cross-linking time is 20-60 min.

16. The method of claim 15, wherein the method comprises: the times of dipping or coating the glucose oxidase and the glutaraldehyde on the working electrode (1) are not less than 3.

Technical Field

The invention relates to the field of needle-shaped sensors for monitoring blood sugar of diabetics in real time, in particular to a three-electrode subcutaneously implanted glucose sensor and a manufacturing method thereof.

Background

The dynamic blood glucose monitoring system (RGMS) is a new type of continuous dynamic blood glucose monitoring system that has been put into clinical use in recent years by attaching one or more probes, like needles, for placement in the subcutaneous tissue. The diameter of the probe is very small, and the patient does not feel pain or discomfort obviously when the probe is placed in the body. The instrument receives an electric signal reflecting blood sugar change from the probe at a certain time interval, and converts the average value of the electric signals collected for a plurality of times into the blood sugar value to be stored. Several hundred blood glucose values can be recorded per day. The dynamic blood glucose monitor can also simultaneously store the time of eating, moving, taking medicine and the like. Therefore, the patient can not suffer from acupuncture every day, and the blood glucose monitoring system can provide a daily blood glucose graph, a multi-day blood glucose graph fluctuation trend analysis and a summary of daily blood glucose data, and is a new breakthrough of blood glucose detection.

In order to improve the accuracy of blood glucose monitoring, the detection needle of the dynamic blood glucose monitor, i.e. the electrode, usually needs the working electrode and the reference electrode to be used in cooperation. The invention patent with publication number CN101530328B, "subcutaneous implanted glucose sensor and manufacturing method thereof" discloses a dual-electrode subcutaneous implanted glucose sensor with a working electrode and a reference electrode, which improves and optimizes the performance, mutual compatibility and consistency of the actual glucose sensor. Although the performance and stability of the sensor are guaranteed to a certain extent, the reference electrode can pass current, and the silver chloride contained in the reference electrode can react with electrons to AgCl + e^-→Ag+Cl^-So that the silver chloride in the silver/silver chloride layer is continuously consumed, and the service life of the reference electrode is influenced; in addition, the sensor electrode is made of more biochemical materials, too complex in process, not beneficial to the control of the electrode quality, high in rejection rate and higher in sensor cost; in particular, the crosslinking of glucose oxidase requires the use of bovine serum albumin or human serum albumin as a carrier, which has a certain biological safety hazard to the human body and increases the possibility of human rejection.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a three-electrode subcutaneous implanted glucose sensor and a manufacturing method thereof, the three-electrode subcutaneous implanted glucose sensor adopts a three-electrode form of a working electrode, a reference electrode and an auxiliary electrode, a tested micro-current passes through the working electrode and the auxiliary electrode, the reference electrode only measures voltage, and basically no current passes through, so that the service life of the reference electrode is prolonged, namely the service life of the sensor is prolonged, and the three-electrode subcutaneous implanted glucose sensor can be implanted and worn for a plurality of days from the original state to half a month to one month; through the improvement of the manufacturing process of the sensor electrode and the simplification of biochemical materials, the complex process becomes simple and the quality is controllable, the cost of the sensor is reduced, the stability of the glucose oxidase of the working electrode is kept through the process improvement, and the accuracy of the test data of the sensor is ensured; in addition, a carrier of glucose oxidase such as bovine serum albumin or human serum albumin is cancelled, the activity and stability of the glucose oxidase are ensured by adopting a mode of coupling double functions of glutaraldehyde and silane, the potential biochemical safety hazard to a human body is reduced, and the rejection reaction of the human body is lightened; through the dismantled and assembled block connected mode of transmitter and sensor for sensor and transmitter can conveniently separate, realize changing behind the sensor transmitter and can also used repeatedly, have reduced user's use cost.

The specific technical scheme of the invention is as follows: a three-electrode subcutaneous implantation type glucose sensor comprises a needle-shaped working electrode, a reference electrode and an auxiliary electrode, wherein the working electrode, the reference electrode and the auxiliary electrode are fixed on a sensor seat;

the working electrode comprises a first conductive substrate, a first metal transition layer, a first noble metal layer, an inner coupling layer, an immobilized enzyme layer, an outer coupling layer and a first polymer film layer from inside to outside;

the reference electrode comprises a second conductive substrate, a second metal transition layer, a silver/silver chloride layer and a second polymer film layer from inside to outside;

the auxiliary electrode comprises a third conductive substrate, a third metal transition layer, a second noble metal layer, a coupling layer and a third polymer film layer from inside to outside.

The sensor used for continuous blood sugar monitoring of the diabetic patient is a consumable product and needs to be replaced regularly, the most key factor influencing the service life of the sensor is the loss of a reference electrode, and when electrons pass through the reference electrode, the silver chloride contained in the reference electrode reacts with the electrons to generate AgCl + e^-→Ag+Cl^-The silver chloride in the silver/silver chloride layer is continuously consumed to influence the service life of the reference electrode, and most of electrons can pass through the auxiliary electrode by adding the auxiliary electrode, so that the consumption of the silver/silver chloride layer is reduced, and the service life of the sensor is prolonged; the working electrode is an electrode which plays a main electrochemical reaction, a biological enzyme which reacts with human blood glucose exists in the working electrode, namely, the immobilized enzyme layer and the first polymer film layer which is used for limiting the reaction amount of the glucose and the biological enzyme are arranged on the outer layer of the immobilized enzyme layer, the immobilized enzyme layer is usually fixed on a carrier in order to improve the stability and keep the activity of the biological enzyme, the immobilized enzyme layer and the first polymer film layer are coupled by adopting a coupling agent, and the carrier usually uses bovine serum albumin or human serum albumin, so that certain biological potential safety hazards exist for a human body.

Preferably, the sensor seat comprises a plastic substrate, three metal connection points which are arranged in a triangular shape and are positioned in the middle of the plastic substrate, a mounting hole is formed in the middle of each metal connection point, and the tail ends of the working electrode, the reference electrode and the auxiliary electrode respectively penetrate through the mounting holes and then are connected and conducted with the metal connection points.

The working electrode, the reference electrode and the auxiliary electrode are arranged on the plastic substrate in a triangular shape, so that the distance among the three electrodes is short, and the monitoring value of blood sugar is more accurate.

Preferably, the three metal connection points are arranged in a regular triangle, and the side length of the regular triangle is 3-6 mm.

When the distance between the working electrode, the reference electrode and the auxiliary electrode is too short, the resistance of the implanted human body is large, when the distance is long, the data deviation of blood glucose monitoring is large, the implanted human body can be smoothly implanted when the distance is 3-6 mm, and the data accuracy of the sensor can be guaranteed.

Preferably, the working electrode, the reference electrode and the auxiliary electrode are all mounted perpendicular to the plastic substrate.

The working electrode, the reference electrode and the auxiliary electrode are implanted into the human body vertically and smoothly, and particularly when an auxiliary wearing tool is used, the vertical implantation is very easy, the human body basically does not have pain, after the vertical implantation, the plastic substrate and the implanted surface of the human body are well attached, and the stability of the implanted sensor can be ensured.

Preferably, the sensor holder further comprises at least three metal contacts on the plastic substrate, the metal contacts are respectively conducted with the metal connection points, and the plastic substrate is provided with a clamping mechanism connected with the emitter.

The emitter provides voltage required by working for the sensor and receives current generated by the sensor electrode, the metal contact is opposite to the contact on the emitter, and when the emitter is clamped and connected with the sensor seat, the metal contact is conducted with the contact on the emitter to realize transmission of current data; the sensor is the consumer, needs the periodic replacement, the transmitter can be used for a long time, through block mechanism can make things convenient for the sensor with the separation of transmitter realizes the used repeatedly of transmitter.

Preferably, an operational amplifier is installed in the transmitter, the reference electrode is electrically connected to an inverting input terminal of the operational amplifier through the metal connection point and the metal contact, and the auxiliary electrode is electrically connected to an output terminal of the operational amplifier through the metal connection point and the metal contact.

The reference electrode is connected with the inverting input end of the operational amplifier, the auxiliary electrode is connected with the output end of the operational amplifier, so that most of current passes through the auxiliary electrode, and the reference electrode has almost no currentThe current flows, i.e. no electrons pass, and the reaction AgCl + e is weakened^-→Ag+Cl^-The service life of the reference electrode is prolonged.

Preferably, the first conductive base material is stainless steel, the first metal transition layer is gold, the first noble metal layer is platinum, the inner coupling layer and the outer coupling layer are silane, the immobilized enzyme layer is glucose oxidase, and the first polymer membrane layer is polyurethane and/or polyethylene glycol.

The first conductive base is preferably made of 304 stainless steel or 316 stainless steel, so that the toughness is good, the human rejection reaction is small, and the safety is high; the immobilized enzyme layer is glucose oxidase which can effectively catalyze glucose + O₂→ gluconic acid + H₂O₂The first polymer film layer is made of polyurethane and/or polyethylene glycol, glucose can be limited from entering the immobilized enzyme layer to participate in the reaction, and sufficient oxygen is guaranteed to participate in the reaction, so that the concentration of the glucose is H₂O₂A factor determining the amount of production; the first metal transition layer is made of gold, and the first noble metal layer is made of platinum and can effectively catalyze H₂O₂→O₂+2H⁺+2e^-Reaction takes place with H₂O₂The generated quantity is converted into an electron generated quantity, electrons pass through the working electrode to generate micro current, and the gold and the platinum can reduce the signal to noise ratio so that the micro current and the glucose concentration are in a linear positive correlation; the inner coupling layer and the outer coupling layer are preferably selected from silane, so that a good coupling effect can be achieved, the stability of the immobilized enzyme layer is improved, the process is simplified, and the quality of the working electrode is controllable.

Preferably, the second conductive base material is stainless steel, the second metal transition layer is silver, and the second polymer film layer is polyurethane and/or polyethylene glycol.

The second conductive substrate is preferably made of 304 stainless steel or 316 stainless steel, so that the toughness is good, the human rejection reaction is small, and the safety is high; the second metal transition layer is silver, and the silver/silver chloride layer is transited outside the silver layer, so that the accuracy and the stability are high.

Preferably, the third conductive base material is stainless steel, the third metal transition layer is gold, the second noble metal layer is platinum, the coupling layer is silane, and the third polymer film layer is polyurethane and/or polyethylene glycol.

The third conductive substrate is preferably made of 304 stainless steel or 316 stainless steel, so that the toughness is good, the human rejection reaction is small, and the safety is high; the third metal transition layer is made of gold, and the second noble metal layer is made of platinum, so that the current signal-to-noise ratio can be reduced, and the current stability after the third metal transition layer and the working electrode form a loop is ensured.

The invention also discloses a manufacturing method of the three-electrode subcutaneous implanted glucose sensor, which comprises the following steps:

the sensor comprises a needle-shaped working electrode, a reference electrode and an auxiliary electrode, wherein the working electrode, the reference electrode and the auxiliary electrode are fixed on a sensor seat;

the working electrode comprises a first conductive base body, a first metal transition layer, a first noble metal layer, an inner coupling layer, an immobilized enzyme layer, an outer coupling layer and a first high polymer film layer from inside to outside, wherein the first conductive base body is made of stainless steel, the first metal transition layer is made of gold, the first noble metal layer is made of platinum, the inner coupling layer and the outer coupling layer are made of silane, the immobilized enzyme layer is glucose oxidase, and the first high polymer film layer is made of polyurethane and/or polyethylene glycol;

the reference electrode comprises a second conductive substrate, a second metal transition layer, a silver/silver chloride layer and a second polymer film layer from inside to outside, wherein the second conductive substrate is made of stainless steel, the second metal transition layer is made of silver, and the second polymer film layer is made of polyurethane and/or polyethylene glycol;

the auxiliary electrode comprises a third conductive base body, a third metal transition layer, a second noble metal layer, a coupling layer and a third high molecular film layer from inside to outside, wherein the third conductive base body is made of stainless steel, the third metal transition layer is made of gold, the second noble metal layer is made of platinum, the coupling layer is made of silane, and the third high molecular film layer is made of polyurethane and/or polyethylene glycol;

the first metal transition layer of the working electrode is covered on the outer layer of the first conductive matrix by adopting a cation etching method; the first noble metal layer is covered on the outer layer of the first metal transition layer by adopting a cation etching method or an electrochemical deposition method; the inner coupling layer is covered on the outer layer of the first noble metal layer in a dipping or coating mode; the immobilized enzyme layer is attached to the outer layer of the inner coupling layer by an enzyme solution in a dipping or coating mode; the outer coupling layer is covered on the outer layer of the immobilized enzyme layer in a dipping or coating mode; the first polymer film layer is covered on the outer layer of the outer coupling layer in a dipping or coating mode.

The working electrode is characterized in that a gold layer is electroplated on the outer layer of the stainless steel needle, a platinum layer is deposited on the outer layer of the gold layer by a cation etching method or an electrochemical deposition method, silane is soaked or coated on the outer layer of the platinum layer, then glucose oxidase is soaked or coated on the outer layer, silane is soaked or coated on the outer layer of the enzyme layer, and finally polyurethane and/or polyethylene glycol is soaked or coated on the outer layer of the enzyme layer.

Preferably, the second metal transition layer of the reference electrode covers the outer layer of the second conductive substrate by a cation etching method; the silver/silver chloride layer is formed by chlorination of the second metal transition layer; the second polymer film layer is covered on the outer layer of the silver/silver chloride layer in a dipping or coating mode.

The reference electrode is used as the reference electrode and can ensure the voltage stability.

Preferably, the third metal transition layer of the auxiliary electrode covers the outer layer of the third conductive substrate by a cation etching method; the second noble metal layer is covered on the outer layer of the third metal transition layer by adopting a cation etching method or an electrochemical deposition method; the coupling layer is covered on the outer layer of the second noble metal layer in a dipping or coating mode; the third high molecular film layer is covered on the outer layer of the coupling layer in a dipping or coating mode.

The auxiliary electrode is equivalent to the working electrode, the glucose oxidase layer is removed, other structures and manufacturing methods are the same as those of the working electrode, and the stability of current after the auxiliary electrode and the working electrode form a loop is guaranteed.

Preferably, the solute of the enzyme solution is glucose oxidase, the solution is a phosphate buffer solution, and the concentration of the glucose oxidase is 0.02-0.2 g/ml.

The glucose oxidase has better activity under the condition that the concentration of the glucose oxidase in the phosphoric acid buffer solution is 0.02 g/ml-0.2 g/ml, and has better effect on the blood sugar catalytic reaction of a human body.

Preferably, the glucose oxidase is cross-linked and cured by glutaraldehyde.

Mixing glutaraldehyde and glucose oxidase solution in a certain proportion, covering the silane layer by adopting a dipping or coating mode, and dipping or coating the silane layer on the outer layer; free glucose oxidase is coupled through double functions of glutaraldehyde and silane, a sandwich layer similar to a sandwich is formed through crosslinking and curing, and free enzyme is combined into an aggregate, so that active sites of the enzyme are denser, the stability is high, and the stable and durable reaction capability is realized in continuous glucose monitoring.

Preferably, the crosslinking temperature of the glucose oxidase and the glutaraldehyde is 25-35 ℃, and the single crosslinking time is 20-60 min.

The glucose oxidase and the glutaraldehyde are crosslinked for 20-60 min at the temperature of 25-35 ℃, so that the enzyme activity is stable, the aggregation is better, and the effect of the blood glucose catalytic reaction of a human body is ensured.

Preferably, the glucose oxidase and the glutaraldehyde are impregnated or coated on the working electrode for not less than 3 times.

Through repeated dipping or coating, the glucose oxidase is more uniformly distributed on the working electrode, the thickness of the immobilized enzyme layer is thicker, the continuous glucose monitoring of a human body is more stable and durable, and the service life of the working electrode is prolonged.

In conclusion, the invention has the following beneficial effects:

1. the three-electrode type sensor is characterized in that a working electrode, a reference electrode and an auxiliary electrode are adopted, the tested micro-current passes through the working electrode and the auxiliary electrode, the reference electrode only measures voltage, and basically no current passes through the reference electrode, so that the service life of the reference electrode is prolonged, namely the service life of the sensor is prolonged, and the sensor is prolonged from being originally implanted and worn for a few days to being implanted and worn for a half month to a month;

2. through the improvement of the manufacturing process of the sensor electrode and the simplification of biochemical materials, the complex process becomes simple and the quality is controllable, the cost of the sensor is reduced, the stability of the glucose oxidase of the working electrode is kept through the process improvement, and the accuracy of the test data of the sensor is ensured;

3. the carrier of glucose oxidase such as bovine serum albumin or human serum albumin is cancelled, the activity and stability of the glucose oxidase are ensured by adopting a mode of coupling double functions of glutaraldehyde and silane, the potential biochemical safety hazard to the human body is reduced, and the rejection reaction of the human body is lightened;

4. through the dismantled and assembled block connected mode of transmitter and sensor for sensor and transmitter can conveniently separate, realize changing behind the sensor transmitter and can also used repeatedly, have reduced user's use cost.

Drawings

FIG. 1 is a perspective view of a sensor of the present invention with the tip side of the sensor electrode facing up;

FIG. 2 is a perspective view of the sensor of the present invention with the tip of the electrode facing downward;

FIG. 3 is a schematic diagram of the construction of the working electrode of the sensor of the present invention;

FIG. 4 is a schematic diagram of a reference electrode of the sensor of the present invention;

FIG. 5 is a schematic diagram of the structure of the auxiliary electrode of the sensor according to the present invention;

FIG. 6 is a schematic diagram of a reference electrode and an auxiliary electrode of a sensor in conjunction with an operational amplifier according to the present invention;

FIG. 7 is a line graph showing the linear correlation variation of the three-electrode sensor and the two-electrode sensor according to the present invention;

FIG. 8 is a comparative graph of a three electrode sensor reference electrode and a two electrode sensor reference electrode test of the present invention;

in the figure, 1-working electrode, 11-first conductive substrate, 12-first metal transition layer, 13-first noble metal layer, 14-inner coupling layer, 15-immobilized enzyme layer, 16-outer coupling layer, 17-first polymer film layer, 2-reference electrode, 21-second conductive substrate, 22-second metal transition layer, 23-silver/silver chloride layer, 24-second polymer film layer, 3-auxiliary electrode, 31-third conductive substrate, 32-third metal transition layer, 33-second noble metal layer, 34-coupling layer, 35-third polymer film layer, 4-sensor seat, 41-plastic substrate, 411-clamping mechanism, 42-metal connection point and 43-metal contact.

Detailed Description

The invention will be further explained by means of specific embodiments with reference to the drawings.