CN116297746A - All-solid-state glucose detection electrode, preparation method thereof and application thereof in blood detection - Google Patents

Abstract

The invention provides an all-solid-state glucose detection electrode, a preparation method thereof and application thereof in blood detection, and particularly comprises an electrode front surface and an electrode back surface, wherein the electrode front surface comprises a plurality of electrode sites, and a plurality of microelectrodes are modified, and the electrode front surface comprises a reference electrode, a counter electrode, a working electrode and a calibration electrode; the electrode front and/or the electrode back are/is provided with electrode contact sites, the electrode contact sites arranged on the electrode front are correspondingly connected with the electrode sites through leads, the electrode contact sites arranged on the electrode back are connected with the conducting through holes through leads, the electrode contact sites are correspondingly connected with the electrode sites through the conducting through holes, and the conducting through holes are arranged at the connecting positions of the electrode sites. The electrode can realize the rapid detection of glucose in blood.

Description

All-solid-state glucose detection electrode, preparation method thereof and application thereof in blood detection

Technical Field

The invention belongs to the field of biological sensors, and particularly relates to an all-solid-state glucose detection electrode, a preparation method thereof and application thereof in blood detection.

Background

The common blood sugar detection modes mainly comprise venous blood sampling and blood sugar meter detection. Venous blood collection requires venous blood collection to a hospital, and examination of glucose tolerance is one of means for diagnosing whether diabetes is present, and since such examination is free from the influence of venous blood and interstitial fluid, the examination accuracy is high, but requires about 2 hours of examination time.

The blood glucose detector adopts an electrochemical principle, and utilizes the blood glucose detection test strip, when the test strip is contacted with blood drops, a blood sample can be automatically sucked into a reaction area of the test strip, so that the operation is simple, quick and convenient. However, the blood glucose test paper is easily affected by the related factors such as ambient temperature, humidity, illumination, chemical substances and the like, and the accuracy of the blood glucose test can be affected by supercooling, overheating and over-wetting environments and pollution of the test paper. If the test paper expires or the test paper becomes stuck with dust or becomes wet due to storage problems, the measured result may deviate. In addition, when the blood glucose meter is used, the condition that the measurement result is inaccurate often appears, and when the blood glucose is high, the error can be bigger, and the function of automatic calibration can not be performed.

In addition, current blood glucose meters measure a single parameter. Diabetes is not just a problem of blood sugar, but blood pressure, blood fat, blood ketone, blood oxygen, heart rate and the like are all important parameters for preventing complications. Therefore, design and development of portable multiparameter blood detectors are of great importance.

Currently, blood glucose test paper is required to be used for blood glucose detection, and the blood glucose test paper is easily influenced by related factors such as ambient temperature, humidity, illumination, chemical substances and the like, so that the accuracy of detection cannot be ensured. Although some blood glucose meters begin to bind various blood gas parameters such as blood pressure, blood oxygen, blood fat, blood ketone and the like which can be measured at home, corresponding test paper needs to be purchased and replaced, so that the use cost is increased, meanwhile, in the test process, blood samples are repeatedly added, so that the blood sampling amount is increased, health hidden danger exists, and automatic calibration cannot be carried out before blood glucose detection, so that the detection accuracy is low and greatly reduced.

In view of the above, the present invention aims to provide a multi-working electrode, a reference electrode, a counter electrode and a calibration electrode detection system, which adopts a dispensing mode to prepare a reaction active layer and an outer membrane layer on the surface of each substrate layer by layer, and detects the glucose content in serum, plasma, whole blood, undiluted urine and aqueous solution through a current test, specifically, through integrating several common parameters of blood biochemistry on the same electrode sheet, one sample feeding, synchronous measurement and completion of rapid and portable multi-parameter detection are realized.

Disclosure of Invention

The invention aims to solve the problems of realizing accurate and rapid detection of glucose in blood and improving the sensitivity and accuracy of detection. In view of the above, the invention provides an all-solid-state glucose detection electrode, a preparation method thereof and application thereof in blood detection.

The invention aims to provide an all-solid-state glucose detection electrode, which specifically comprises an electrode front surface and an electrode back surface, wherein the electrode front surface comprises a plurality of electrode sites, and a plurality of microelectrodes are modified, and the electrode front surface comprises a reference electrode, a counter electrode, a working electrode and a calibration electrode; the electrode front and/or the electrode back are/is provided with electrode contact sites, the electrode contact sites arranged on the electrode front are correspondingly connected with the electrode sites through leads, the electrode contact sites arranged on the electrode back are connected with the conducting through holes through leads, the electrode contact sites are correspondingly connected with the electrode sites through the conducting through holes, and the conducting through holes are arranged at the connecting positions of the electrode sites.

The surface of the electrode site is provided with a substrate electrode and an all-solid-state modifier on the surface of the substrate electrode, and the all-solid-state modifier comprises a buffer layer (1), conductive polymer gel (2) and a protective layer (3).

The microelectrode adopts a multi-layer ink processing technology to form an ink dam in a concentric circle shape, the diameter of the concentric circle is 0.2-1.5 mm, and the center distance of the concentric circle is 20-150 mu m; the ink box dam is processed by PCB solder resist ink, and the thickness is 20-50 mu m.

The reference electrode includes a base electrode, a silver paste layer, and an outer film layer.

Further, the substrate electrode comprises gold, silver, platinum, carbon.

Further, the silver paste layer is modified on the surface of the substrate electrode.

Further, the outer film layer is modified on the surface of the silver paste layer.

The counter electrode comprises a platinum electrode, a gold electrode and a carbon electrode.

The working electrode comprises a base electrode, a phosphate buffer layer, an enzyme-conductive polymer gel layer and a PVC protective layer.

The PVC protective layer is used as an outer membrane layer to protect the enzyme layer from direct pollution of detection substances, the outer membrane also needs to have certain hydrophilicity and hydrophobicity, so that the detected glucose molecules can enter the sensor through the outer membrane, and meanwhile, oxygen can enter the enzyme layer through the outer membrane to participate in the reaction.

Further, the substrate electrode comprises a platinum electrode, and particularly a platinum layer is modified on the surface of the gold electrode.

The platinum electrode is used as a base electrode of the working electrode, so that the electrode is suitable for current type detection, is more stable and less prone to damage than a pure gold electrode, the current distortion problem is avoided, the electrode stability is enhanced, and the electrode is suitable for glucose biochemical molecular detection.

Referring to fig. 1 and 2, a front view and a back view of an all solid-state glucose electrode according to the present invention are shown.

Five microelectrodes are arranged on the front face of the electrode, namely a reference electrode R, a counter electrode C1, a working electrode W2 and a calibration electrode C2, wherein a microelectrode detection site area is processed by adopting metal Pad points, and the metal Pad points are correspondingly connected with electrode contact sites on the back face of the electrode through metal leads or connected through holes.

The electrode contact sites can be arranged on the front surface or the back surface of the electrode as required, the front surface contact sites can be correspondingly connected with the microelectrode detection sites directly through metal circuits, and the back surface contact sites can be correspondingly connected with the microelectrode detection sites through metal circuit connection via holes.

Fig. 3 is a schematic diagram of the structure of the all-solid-state glucose detection electrode according to the present invention. From the figure, the surface of the substrate electrode is modified with an all-solid-state modifier, which comprises a buffer layer (1), conductive polymer gel (2) and a protective layer (3) from inside to outside, wherein the buffer layer (1) is a potassium ferricyanide and phosphate layer, then the conductive polymer gel (2) is modified, and the surface of the conductive polymer gel is covered with the protective layer (3), namely a PVC protective layer, and all the modified structures adopt all-solid-state structures, so that the overall stability of the electrode can be greatly improved.

Another object of the present invention is to provide a method for preparing an all-solid-state glucose detection electrode, comprising the steps of:

s1, preparing the reference electrode:

(1) Preparation of silver paste layer: selecting a gold electrode, a silver electrode, a platinum electrode or a carbon electrode as a substrate electrode, and spot-coating 1-10 mu L of Ag/AgCl slurry on the surface of the substrate by using a spot gluing machine;

(2) Preparation of the outer film layer: adding 1-5% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain an outer film solution, then dripping 1-10 mu L of the outer film solution on the surface of the silver paste layer, and drying for 2-5 h to obtain a reference electrode;

s2, preparing the working electrode:

(1) Preparation of phosphate buffer layer: selecting a gold electrode, a silver electrode, a platinum electrode or a carbon electrode as a substrate electrode, adding 1-10 mmol/L ferrocene and 100-300 mmol/L NaCl into 10-20 mmol/LPBS solution, performing ultrasonic treatment for 1-5 min to obtain a phosphate buffer solution, dispensing 1-5 mu L of the phosphate buffer solution on the surface of the substrate electrode by using a dispenser, and drying for 2-5 h to form a phosphate buffer layer;

(2) Preparation of enzyme & conductive polymer gel layer: mixing 1-5 mg/L glucose oxidase, 0.05-0.1% PVA (5% mother liquor) and 2-3% polyethylenimine, oscillating for 1-5 min, carrying out ultrasonic treatment for 1-5 min until the glucose oxidase and the polyethylenimine are fully dissolved to obtain a gel solution, then applying 2-10 mu L of the gel solution to the surface of a phosphate buffer layer by using a dispensing machine, and drying for 2-5 h to form an enzyme-conductive polymer gel layer;

(3) Preparation of a PVC protective layer: adding 1-5% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain protective layer solution, then spot-coating 1-10 mu L of the protective layer solution on the surface of enzyme-conductive polymer gel layer by using a dispensing machine, and drying for 2-5 h to obtain the working electrode.

The PVA described above may be replaced with PREDOT: PSS hydrogel layer, PREDOT: the PSS hydrogel layer has good conductivity and large electroactive surface area, and can better realize the conductive effect.

The invention also aims to provide an application of the all-solid-state glucose detection electrode in blood detection, and particularly, the rapid detection of glucose in blood can be realized.

The all-solid-state glucose detection electrode prepared by the invention is a current type sensor, a constant voltage is applied by adopting an instant Current (CA) method, the change of current along with time is tested, and simultaneously, the current is combined with a cyclic voltammetry method to test and verify the performance of the glucose electrode.

And placing the electrode into the solution to be measured, forming a battery by the working electrode and the reference electrode, and measuring the potential difference of the working electrode and the reference electrode. According to the Nernst equation, the potential difference is in linear relation with the logarithm of the concentration of the ions to be detected, so that the concentration of glucose is detected. For ion selective electrodes, the base voltages of the different electrodes tend to be different, and even with the same electrode, the voltage is prone to drift. Calibration is required before actual measurement. The working electrode is calibrated using a calibration electrode.

As shown in figure 4, the cyclic voltammogram of the all-solid-state glucose detection electrode for detecting glucose is shown in the invention, the scanning potential range is specifically set to be-0.4-0.8V, the scanning speed is 0.05V/s, and glucose linear liquids with different concentrations are tested to obtain corresponding graphs of current changing along with the potential, wherein the concentration of the glucose linear liquid is 5mmol/L, 10mmol/L, 15mmol/L, 20mmol/L and 40mmol/L respectively. As can be seen from the graph, as the concentration of glucose increases, the current response of the electrode gradually increases, which proves that the prepared all-solid-state glucose detection electrode has good response performance to glucose with different concentrations.

As shown in FIG. 5, a timing amperometric test chart of the all-solid-state glucose detection electrode for detecting glucose is shown, wherein the constant voltage is specifically set to be 0.65V, the test time is 100s, and a timing amperometric test is adopted to measure a change curve of current and a fitting curve of concentration and current of the electrode prepared by the invention within 100 s. As can be seen from the graph, the response curves of the glucose linear solutions of 5mmol/L, 10mmol/L, 15mmol/L, 20mmol/L and 40mmol/L can reach a stable state within 1s, and the response curves tend to be stable within a test time range of 100s, so that the all-solid-state glucose detection electrode prepared by the invention has good electrochemical performance for detecting glucose.

As shown in FIG. 6, a curve of the timing current versus time for testing glucose for all-solid-state glucose sensing electrodes of the present invention is shown. As can be seen from the graph, the response current and the glucose concentration have good linear relation with the change of the glucose concentration, and the linearity R ² The value is 0.982, which shows that the prepared all-solid-state glucose detection electrode can realize accurate response to glucose.

As shown in FIG. 7, the cyclic voltammogram of the all-solid-state glucose detection electrode for detecting glucose with different concentrations is shown, and specifically, the response performance of the electrode to glucose linear solutions of 5mmol/L, 10mmol/L, 15mmol/L, 20mmol/L and 40mmol/L is tested. As can be seen from the graph, the cyclic voltammogram of the electrode, which scans within the range of-0.4 to 0.8V, shows an obvious oxidation peak at the potential of 0.22V and a reduction peak at the potential of 0.05V, which shows that the all-solid-state glucose detection electrode prepared by the invention has obvious catalytic performance on glucose.

FIG. 8 is a graph showing the stability test of the all-solid-state glucose test electrode of the present invention. As can be seen from the graph, no significant fluctuations in response current occurred in the seven day continuous monitoring. According to calculation, the glucose response signal of the electrode is reduced by 3.41% in seven days compared with the glucose response signal of the electrode in the first day, so that the all-solid-state glucose detection electrode prepared by the invention has good stability.

The beneficial effects of the invention are as follows:

(1) The invention develops the multi-parameter integrated sensing electrode, can simultaneously realize the instant detection of multiple parameters in blood, has small blood sampling amount, realizes one-time sample adding and synchronous measurement, completes the rapid and portable detection of multiple parameters, has accurate test result, simple operation and low cost, and is not influenced by conditions such as ambient temperature, humidity and the like.

(2) According to the invention, the surface of the microelectrode is modified with a multilayer structure, so that the overall detection performance of the electrode for glucose is improved, meanwhile, the selective electrode layer is prepared layer by layer in a dispensing mode, the operation is simple, and the processing cost and the process difficulty are reduced. The three-electrode system is set to be an electrode structure with five microelectrodes integrated to greatly detect the stability of the electrode, and the calibration electrode is set, so that the electrode self-calibration function is realized, the electrode can be automatically calibrated in the test process, the test accuracy is ensured, the service life of the electrode is prolonged, the calibration electrode can be used as a working electrode at the same time, and the stability and the sensitivity of the electrode are greatly improved on the basis of simultaneously detecting a plurality of indexes at one time for single detection of a certain target.

(3) According to the invention, a plurality of microelectrode detection sites are integrated on the surface of the same electrode, and are connected with electrode contact sites in different modes such as lead connection, via connection and the like, so that the chip area is greatly saved, the purpose of microelectrode integration is realized, the structure design of the connection circuit of the microelectrode and a metal pin is simplified, the processing difficulty and cost are reduced, multi-parameter blood gas detection of multiple detection, low cost and trace samples is realized, and a foundation is laid for the integrated low-cost portable multi-parameter sensor application.

Drawings

The invention will be further described with reference to the accompanying drawings, in which embodiments do not constitute any limitation of the invention, and other drawings can be obtained by one of ordinary skill in the art without inventive effort from the following drawings.

FIG. 1 is a schematic front view of an all-solid-state glucose sensing electrode;

FIG. 2 is a schematic rear view of an all-solid-state glucose sensing electrode;

FIG. 3 is a schematic diagram of an all-solid-state glucose sensing electrode structure;

FIG. 4 is a cyclic voltammogram of an all solid state glucose sensing electrode sensing glucose;

FIG. 5 is a chronoamperometric test chart of an all solid-state glucose sensing electrode sensing glucose;

FIG. 6 is a plot of the timing current versus time for an all solid state glucose sensing electrode testing glucose;

FIG. 7 is a cyclic voltammogram of an all solid-state glucose detection electrode detecting glucose at different concentrations;

FIG. 8 is a graph showing stability test of all solid-state glucose test electrodes.

Legend description:

1. a buffer layer; 2. conducting polymer gel; 3. protective layer

Detailed Description

The invention will be further described in detail with reference to the following specific examples, with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the invention more apparent.

Example 1

As shown in fig. 1 and 2, the front surface of the electrode comprises 5 electrode sites, microelectrodes are modified on the electrode sites, and are respectively a reference electrode R, a counter electrode C1, a working electrode W2 and a calibration electrode C2, wherein the working electrode W1 and the working electrode W2 are all solid-state glucose detection electrodes, and the calibration electrode C2 can be set to be of the same electrode structure as the working electrode.

The back of the electrode is provided with an electrode contact site which is connected with the through hole through a lead wire and correspondingly connected with the electrode site through the through hole, and the connecting position of the electrode site is provided with the through hole.

The surface of the electrode site is provided with a substrate electrode and an all-solid-state modifier on the surface of the substrate electrode, and the all-solid-state modifier comprises a buffer layer 1, conductive polymer gel 2 and a protective layer 3.

The reference electrode R, the counter electrode C1, the working electrode W2 and the calibration electrode C are all three-layer ink dams processed by PCB solder resist ink, so that the concentric-circle-shaped ink dams are formed.

The first layer of ink covers the surface of the metal electrode to form an electrode detection area, the diameter is 0.45mm, the second layer of ink covers the first layer of ink to form a concentric circle line surrounding dam, the diameter is 0.55mm, the third layer of ink covers the second layer of ink to form a concentric circle line surrounding dam, the diameter is 0.65mm, and the thickness of each layer of ink is 20-50 mu m.

The reference electrode includes a base electrode, a silver paste layer, and an outer film layer.

Wherein the substrate electrode comprises gold, silver, platinum and carbon; the silver paste layer is modified on the surface of the substrate electrode; the outer film layer is modified on the surface of the silver paste layer.

The counter electrode comprises a platinum electrode, a gold electrode and a carbon electrode.

The working electrode comprises a base electrode, a phosphate buffer layer, an enzyme-conductive polymer gel layer and a PVC protective layer.

The substrate electrode comprises a platinum electrode, and particularly a platinum layer is modified on the surface of the gold electrode; the phosphate buffer layer is modified on the surface of the substrate electrode, the enzyme and conductive polymer gel layer is modified on the surface of the phosphate buffer layer, and the PVC protective layer is modified on the surface of the enzyme and conductive polymer gel layer.

Positioning holes are formed in four corners of the electrode, and the aperture is 0.25mm and used for fixing the electrode.

Example 2

Preparation of all-solid-state glucose detection electrode:

s1, preparing the reference electrode:

(1) Preparation of silver paste layer: selecting a gold electrode as a substrate electrode, and dispensing 1-10 mu L of Ag/AgCl slurry on the surface of the substrate by using a dispenser;

(2) Preparation of an outer film layer, namely adding 1% carboxyl PVC-COOH into cyclohexanone solvent, uniformly stirring to obtain an outer film solution, then dripping 2 mu L of the outer film solution on the surface of a silver paste layer, and drying for 2 hours to obtain a reference electrode;

s2, preparing the working electrode:

(1) Preparation of phosphate buffer layer: selecting a platinum electrode as a substrate electrode, adding 1-10 mmol/L ferrocene and 100-300 mmol/L NaCl into 10-20 mmol/LPBS solution, performing ultrasonic treatment for 1-5 min to obtain a phosphate buffer solution, dispensing 1-5 mu L of the phosphate buffer solution on the surface of the substrate electrode by using a dispenser, and drying for 2-5 h to form a phosphate buffer layer;

(2) Preparing an enzyme & conductive polymer gel layer, namely mixing 1-5 mg/L glucose oxidase, 0.05-0.10% PVA (5% mother liquor) and 2-3% polyethyleneimine, vibrating for 1-5 min, performing ultrasonic treatment for 1-5 min until the mixture is fully dissolved to obtain a gel solution, then spot-coating 2-10 mu L of the gel solution on the surface of a phosphate buffer layer by using a dispensing machine, and drying for 2-5 h to form the enzyme & conductive polymer gel layer;

(3) Preparation of a PVC protective layer: adding 1-5% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain protective layer solution, then spot-coating 1-10 mu L of the protective layer solution on the surface of enzyme-conductive polymer gel layer by using a dispensing machine, and drying for 2-5 h to obtain the working electrode.

Example 3

Preparation of all-solid-state glucose detection electrode:

s1, preparing the reference electrode:

(1) Preparation of silver paste layer: selecting a gold electrode as a substrate electrode, and dispensing 2 mu L of Ag/AgCl slurry on the surface of the substrate by using a dispenser;

(2) Preparation of the outer film layer: adding 5% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain an outer film solution, then dripping 5 mu L of the outer film solution on the surface of the silver paste layer, and drying for 5 hours to obtain a reference electrode;

s2, preparing the working electrode:

(1) Preparation of phosphate buffer layer: selecting a platinum electrode as a substrate electrode, adding 10mmol/L ferrocene and 300mmol/L NaCl into 20mmol/LPBS solution, performing ultrasonic treatment for 5min to obtain a phosphate buffer solution, dispensing 1 mu L of the phosphate buffer solution on the surface of the substrate electrode by using a dispenser, and drying for 5h to form a phosphate buffer layer;

(2) Preparation of enzyme & conductive polymer gel layer: mixing 5mg/L glucose oxidase, 0.10% PVA (5% mother liquor) and 3% polyethylenimine, oscillating for 5min, performing ultrasonic treatment for 5min until the mixture is fully dissolved to obtain a gel solution, then spot-coating 2 mu L of the gel solution on the surface of a phosphate buffer layer by using a dispensing machine, and drying for 5h to form an enzyme-conductive polymer gel layer;

(3) Preparation of a PVC protective layer: adding 5% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain protective layer solution, then applying 5 mu L of the protective layer solution on the surface of enzyme-conductive polymer gel layer by using a dispenser, and drying for 5 hours to obtain the working electrode.

Example 4

Preparation of all-solid-state glucose detection electrode:

s1, preparation of the reference electrode:

(1) Preparation of silver paste layer: selecting a gold electrode as a substrate electrode, and dispensing 2 mu L of Ag/AgCl slurry on the surface of the substrate by using a dispenser;

(2) Preparation of the outer film layer: adding 2% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain an outer film solution, then dripping 5 mu L of the outer film solution on the surface of a silver paste layer, and drying for 3 hours to obtain a reference electrode;

s2, preparing the working electrode:

(1) Preparation of phosphate buffer layer: selecting a platinum electrode as a substrate electrode, adding 5mmol/L ferrocene and 200mmol/L NaCl into 10mmol/LPBS solution, performing ultrasonic treatment for 3min to obtain a phosphate buffer solution, dispensing 2 mu L of the phosphate buffer solution on the surface of the substrate electrode by using a dispenser, and drying for 3h to form a phosphate buffer layer;

(2) Preparation of enzyme & conductive polymer gel layer: mixing 2mg/L glucose oxidase, 0.05% PVA (5% mother liquor) and 2% polyethylenimine, oscillating for 3min, performing ultrasonic treatment for 3min until the mixture is fully dissolved to obtain a gel solution, then spot-coating 3 mu L of the gel solution on the surface of a phosphate buffer layer by using a dispensing machine, and drying for 3h to form an enzyme-conductive polymer gel layer;

(3) Preparation of a PVC protective layer: adding 2% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain protective layer solution, then applying 5 mu L of the protective layer solution on the surface of enzyme-conductive polymer gel layer by using a dispenser, and drying for 3 hours to obtain the working electrode.

Example 5

Preparation of all-solid-state glucose detection electrode:

s1, preparing the reference electrode:

(1) Preparation of silver paste layer: selecting a gold electrode as a substrate electrode, and dispensing 2 mu L of Ag/AgCl slurry on the surface of the substrate by using a dispenser;

(2) Preparation of the outer film layer: adding 3% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain an outer film solution, then dripping 5 mu L of the outer film solution on the surface of a silver paste layer, and drying for 5 hours to obtain a reference electrode;

s2, preparing the working electrode:

(1) Preparation of phosphate buffer layer: selecting a platinum electrode as a substrate electrode, adding 8mmol/L ferrocene and 200mmol/L NaCl into 15mmol/LPBS solution, performing ultrasonic treatment for 5min to obtain a phosphate buffer solution, dispensing 1 mu L of the phosphate buffer solution on the surface of the substrate electrode by using a dispenser, and drying for 5h to form a phosphate buffer layer;

(2) Preparation of enzyme & conductive polymer gel layer: mixing 3mg/L glucose oxidase, 0.08% PVA (5% mother liquor) and 3% polyethylenimine, oscillating for 3min, performing ultrasonic treatment for 3min until the mixture is fully dissolved to obtain a gel solution, then spot-coating 2 mu L of the gel solution on the surface of a phosphate buffer layer by using a dispensing machine, and drying for 5h to form an enzyme-conductive polymer gel layer;

(3) Preparation of a PVC protective layer: adding 3% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain protective layer solution, then applying 5 mu L of the protective layer solution on the surface of enzyme-conductive polymer gel layer by using a dispenser, and drying for 5 hours to obtain the working electrode.

Example 6

The application of the all-solid-state glucose detection electrode in glucose detection:

the electrode performance was measured by cyclic voltammetry using the all solid-state glucose test electrode prepared in example 2.

The glucose solutions with different concentrations are tested by using electrodes, the concentrations are 5mmol/L, 10mmol/L, 15mmol/L, 20mmol/L and 40mmol/L respectively, the scanning potential range is set to be-0.4V-0.8V, the scanning speed is set to be 0.05V/s, and the glucose linear solutions with different concentrations are tested to obtain a graph of corresponding current changing along with potential, namely, figure 4. With the increase of the glucose concentration, the current response of the electrode gradually increases, which shows that the prepared all-solid-state glucose detection electrode has good response performance to glucose with different concentrations.

Example 7

The application of the all-solid-state glucose detection electrode in glucose detection:

the electrode performance was measured by a chronoamperometry using the all solid-state glucose test electrode prepared in example 2.

The glucose solution was tested using electrodes, a constant voltage of 0.65V was set, the test time was 100s, and the test electrodes detected glucose linear solutions of different concentrations, resulting in a corresponding graph of current change over time, i.e. fig. 5. For the glucose linear solutions of 5mmol/L, 10mmol/L, 15mmol/L, 20mmol/L and 40mmol/L, the response curve can reach a stable state within 1s, and the response curve tends to be stable within the test time range of 100s, and the result shows that the prepared all-solid-state glucose detection electrode has good electrochemical response performance and can be used for detecting glucose molecules.

Fitting the time-dependent response current to the glucose concentration gives the graph of fig. 6, which shows a good linear relationship with respect to the glucose concentration with the change in glucose concentration, with the fitting equation y= 5.157 ×10 ^-10 x+1.9×10 ^-8 Wherein R is ² =0.982, indicating that the electrode prepared according to the invention can achieve a precise response to glucose.

Example 8

The application of the all-solid-state glucose detection electrode in glucose detection:

the sensing response performance of glucose was tested by using the all solid-state glucose sensing electrode prepared in example 3.

The electrodes were put into glucose having concentrations of 5mmol/L, 10mmol/L, 15mmol/L, 20mmol/L, and 40mmol/L, respectively, and cyclic voltammetry was performed to obtain FIG. 7. Scanning is carried out within the range of-0.4-0.8V, the cyclic voltammetry curve of the electrode has obvious oxidation peak at the potential of 0.22V and reduction peak at the potential of 0.05V, which shows that the electrode prepared by the invention has obvious catalytic performance on glucose and can realize accurate response on glucose.

Example 9

The application of the all-solid-state glucose detection electrode in glucose detection:

the stability of the all solid-state glucose test electrode prepared in example 3 was tested.

After the electrode was stored at room temperature for 7 days, the change of the response current to glucose was measured, after each measurement was completed, the electrode was washed and dried, and then stored at room temperature, and the change of the response current to 15mM glucose in one week was recorded, to obtain FIG. 8. In a seven day continuous monitoring, no significant fluctuations in response current occurred. By calculation, the electrode was 3.41% lower in glucose response signal after seven days compared to the first day. The invention shows that the prepared all-solid-state glucose detection electrode has good stability.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined appropriately to form other embodiments that will be understood by those skilled in the art. Technical details not described in detail in the present invention may be implemented by any prior art in the field. In particular, all technical features not described in detail in this invention can be realized by any prior art technique.

Claims (9)

1. The all-solid-state glucose detection electrode is characterized by comprising an electrode front surface and an electrode back surface, wherein the electrode front surface comprises a plurality of electrode sites, is modified with a plurality of microelectrodes and comprises a reference electrode, a counter electrode, a working electrode and a calibration electrode; the electrode front and/or the electrode back are/is provided with electrode contact sites, the electrode contact sites arranged on the electrode front are correspondingly connected with the electrode sites through leads, the electrode contact sites arranged on the electrode back are connected with the conducting through holes through leads and are correspondingly connected with the electrode sites through the conducting through holes, and the connecting positions of the electrode sites are provided with the conducting through holes; the electrode site surface is provided with a substrate electrode and an all-solid-state modifier on the surface of the substrate electrode, and the all-solid-state modifier comprises a buffer layer (1), conductive polymer gel (2) and a protective layer (3).

2. The all-solid-state glucose detection electrode according to claim 1, wherein the microelectrode adopts a multi-layer ink processing technology to form an ink dam in a concentric circle shape, the diameter of the concentric circle is 0.2-1.5 mm, and the center distance of the concentric circle is 20-150 μm; the ink box dam is processed by PCB solder resist ink, and the thickness is 20-50 mu m.

3. The all-solid-state glucose sensing electrode of claim 1, wherein the reference electrode comprises a base electrode, a silver paste layer and an outer film layer.

4. An all-solid-state glucose sensing electrode according to claim 3, wherein the base electrode comprises gold, silver, platinum, carbon; the silver paste layer is modified on the surface of the substrate electrode; the outer film layer is modified on the surface of the silver paste layer.

5. An all-solid-state glucose test electrode according to claim 1, wherein the counter electrode comprises a platinum electrode, a gold electrode, a carbon electrode.

6. The all-solid-state glucose test electrode according to claim 1, wherein the working electrode comprises a base electrode, a phosphate buffer layer, an enzyme & conductive polymer gel layer, and a PVC protective layer.

7. The all-solid-state glucose detection electrode according to claim 6, wherein the substrate electrode comprises a platinum electrode, in particular a platinum layer modified on the surface of a gold electrode.

8. A method of making an all-solid-state glucose sensing electrode according to claim 1, comprising the steps of:

s1, preparing the reference electrode:

(1) Preparation of silver paste layer: selecting a gold electrode, a silver electrode, a platinum electrode or a carbon electrode as a substrate electrode, and spot-coating 1-10 mu L of Ag/AgCl slurry on the surface of the substrate by using a spot gluing machine;

(2) Preparation of the outer film layer: adding 1-5% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain an outer film solution, then dripping 1-10 mu L of the outer film solution on the surface of the silver paste layer, and drying for 2-5 h to obtain a reference electrode;

s2, preparing the working electrode:

(1) Preparation of phosphate buffer layer: selecting a gold electrode, a silver electrode, a platinum electrode or a carbon electrode as a substrate electrode, adding 1-10 mmol/L ferrocene and 100-300 mmol/L NaCl into 10-20 mmol/L PBS solution, performing ultrasonic treatment for 1-5 min to obtain a phosphate buffer solution, dispensing 1-5 mu L of the phosphate buffer solution on the surface of the substrate electrode by using a dispenser, and drying for 2-5 h to form a phosphate buffer layer;

(2) Preparing an enzyme & conductive polymer gel layer, namely mixing 1-5 mg/L glucose oxidase, 0.05-0.10% PVA (5% mother liquor) and 2-3% polyethyleneimine, vibrating for 1-5 min, performing ultrasonic treatment for 1-5 min until the mixture is fully dissolved to obtain a gel solution, then spot-coating 2-10 mu L of the gel solution on the surface of a phosphate buffer layer by using a dispensing machine, and drying for 2-5 h to form the enzyme & conductive polymer gel layer;

(3) Preparation of a PVC protective layer: adding 1-5% carboxyl PVC-COOH into cyclohexanone solvent, stirring uniformly to obtain protective layer solution, then spot-coating 1-10 mu L of the protective layer solution on the surface of enzyme-conductive polymer gel layer by using a dispensing machine, and drying for 2-5 h to obtain the working electrode.

9. Use of an all solid state glucose detection electrode according to any one of claims 1-8 for blood detection, wherein the electrode enables rapid detection of glucose in blood.

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