A bifunctional sensor for simultaneous detection of uric acid and glucose, its preparation method and application

Abstract

This invention belongs to the field of biosensor technology, specifically relating to a bifunctional sensor for the simultaneous detection of uric acid and glucose, its preparation method, and its applications. The bifunctional sensor for the simultaneous detection of uric acid and glucose provided by this invention includes a substrate and, disposed on the substrate, a uric acid sensing working electrode, a glucose sensing working electrode, a reference electrode, a counter electrode, electrode interfaces of the aforementioned electrodes, and conductive traces connecting the aforementioned electrodes and electrode interfaces. This bifunctional sensor can simultaneously or selectively measure uric acid and glucose. Through modification of the working electrode, it can achieve high sensitivity and a wide linear detection range, exhibiting linear sensing ranges of 0–2 mM and 0–10 mM for uric acid and glucose, respectively, effectively covering their concentration ranges under physiological conditions. This bifunctional sensor has the advantages of high sensitivity and a wide linear detection range, enabling rapid and accurate detection, and has practical application potential.

Description

Technical Field

[0001] This invention belongs to the field of biosensor technology, specifically relating to a dual-function sensor that simultaneously detects uric acid and glucose, its preparation method, and its application. Background Technology

[0002] Diabetes is one of the most serious chronic diseases threatening human health worldwide, and blood glucose levels are an important criterion for diagnosing diabetes. Furthermore, persistently elevated uric acid levels in the blood lead to hyperuricemia, which can cause gout, hypertension, kidney stones and kidney damage, cardiovascular disease, and other health problems. Elevated blood uric acid levels are also considered one of the best independent predictors of diabetes.

[0003] Currently, the detection of blood glucose levels and uric acid concentrations heavily relies on blood analysis, but blood analysis is an invasive method that inevitably causes pain and psychological stress for subjects. Therefore, monitoring the concentration of molecules related to physiological metabolism in bodily fluids has become a widely adopted health management and treatment strategy. Human bodily fluids (such as sweat, urine, tears, and interstitial fluid) contain abundant physiological information, and sampling them allows for non-invasive detection. For example, uric acid and blood glucose levels in sweat show a good correlation with those in blood. Consequently, extensive research has been conducted on uric acid and glucose detection based on electrochemical platforms.

[0004] Chinese patent document CN215218661U discloses an electrochemical sensor array that can be used to simultaneously detect creatinine, glucose, and uric acid. The basic principle of each working electrode in this novel sensor array is based on the reaction of the target analyte with an enzyme to generate hydrogen peroxide, which is then catalytically reduced by an electron mediator. The resulting sensor array is convenient for the simultaneous detection of creatinine, glucose, and uric acid. However, this sensor cannot guarantee that the detection range for each indicator covers the physiological concentration range. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-function sensor for the simultaneous detection of uric acid and glucose, its preparation method, and its application. The dual-function sensor provided by this invention has high sensitivity and a wide linear detection range.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The present invention provides a dual-function sensor for simultaneously detecting uric acid and glucose, comprising a substrate and a uric acid sensing working electrode, a glucose sensing working electrode, a reference electrode, a counter electrode disposed on the substrate, an electrode interface of the above electrodes, and a conductive trace connecting the above electrodes and the electrode interface.

[0008] The uric acid sensing working electrode comprises a first graphite carbon layer, a first Prussian blue layer, and a uricase layer stacked from bottom to top; the uricase layer comprises uricase, carbon nanotubes, and chitosan.

[0009] The glucose sensing working electrode comprises, from bottom to top, a second graphite carbon layer, a gold layer, a carbon nanotube layer, a second Prussian blue layer, and a glucose oxidase layer.

[0010] Preferably, the substrate is a flexible substrate; the size of the dual-function sensor is 125–200 mm. 2 ;

[0011] The substrate surface is sequentially provided with a uric acid sensing working electrode and its electrode interface and conductive trajectory, a reference electrode and its electrode interface and conductive trajectory, a counter electrode and its electrode interface and conductive trajectory, and a glucose sensing working electrode and its electrode interface and conductive trajectory; the conductive trajectory of the uric acid sensing working electrode, the conductive trajectory of the reference electrode, and the conductive trajectory of the glucose sensing working electrode extend towards the counter electrode at right angles.

[0012] Preferably, the uric acid sensing working electrode is circular; the area of ​​the uric acid sensing working electrode is 2.01–7.065 mm². 2 .

[0013] Preferably, the glucose sensing working electrode is circular; the area of ​​the glucose sensing working electrode is 2.01–7.065 mm². 2 ;

[0014] The raw materials for the glucose oxidase layer include glucose oxidase, glutaraldehyde, and bovine serum albumin.

[0015] Preferably, the reference electrode is an Ag / AgCl electrode; the reference electrode is circular; and the area of ​​the reference electrode is 2.01–7.065 mm². 2 .

[0016] The counter electrode is a graphite electrode; the counter electrode is zigzag-shaped; the total length of the counter electrode is 12-16 mm, and the width is 0.8-1.1 mm.

[0017] The present invention also provides a method for fabricating the dual-function sensor described in the above technical solution, characterized by comprising the following steps:

[0018] Conductive traces and electrode interfaces of a uric acid sensing working electrode, a glucose sensing working electrode, a reference electrode, and a counter electrode are fabricated on the substrate surface.

[0019] The graphite carbon paste is screen-printed at the ends of the conductive traces of the uric acid sensing working electrode, the glucose sensing working electrode and the counter electrode to obtain a first graphite carbon layer, a second graphite carbon layer and a counter electrode.

[0020] A mixed solution of a first iron salt and ferricyanide is coated onto the surface of the first graphite carbon layer, followed by a first deposition and a first activation to obtain a first Prussian blue layer; a uricase solution is then coated onto the surface of the first Prussian blue layer to obtain a uricase layer, which is the uric acid sensing working electrode; the solute of the uricase solution includes uricase, carbon nanotubes and chitosan.

[0021] Metallographic deposition is performed on the surface of the second graphite carbon layer to obtain a gold layer; a carbon nanotube dispersion is coated on the surface of the gold layer to obtain a carbon nanotube layer; a mixed solution of a second iron salt and ferricyanide is coated on the surface of the carbon nanotube layer, and a second deposition and a second activation are performed sequentially to obtain a second Prussian blue layer; a glucose oxidase solution is coated on the surface of the second Prussian blue layer to obtain a glucose oxidase layer, which is the glucose sensing working electrode.

[0022] A second screen printing process is performed on the end of the conductive trace of the reference electrode using silver-silver chloride ink to obtain the reference electrode, thus obtaining the dual-function sensor.

[0023] Preferably, the first deposition and the second deposition are independently electrodeposition; the voltage of the electrodeposition is 0.4 to 0.8 V and the time is 60 to 120 s.

[0024] Preferably, the reagents for the first and second activations are independently a mixed solution of hydrogen chloride and chloride salt; the first and second activations are independently performed using cyclic voltammetry; the voltage of the cyclic voltammetry is -0.2 to 0.6 V, the scan rate is 50 to 100 mV / s, and the number of cycles is 18 to 24.

[0025] Preferably, the mass ratio of uricase, carbon nanotubes and chitosan is 5:2:10 to 42;

[0026] The solutes in the glucose oxidase solution include glucose oxidase, glutaraldehyde, and bovine serum albumin; the mass ratio of glucose oxidase, glutaraldehyde, and bovine serum albumin is 30-60:26:40.

[0027] The present invention also provides the application of the dual-function sensor described in the above technical solution or the dual-function sensor prepared by the preparation method described in the above technical solution in the preparation of wearable products.

[0028] This invention provides a dual-function sensor for simultaneously detecting uric acid and glucose, comprising a substrate and a uric acid sensing electrode, a glucose sensing electrode, a reference electrode, a counter electrode, electrode interfaces of the electrodes, and conductive traces connecting the electrodes and electrode interfaces, all disposed on the substrate. The uric acid sensing electrode comprises a first graphite carbon layer, a first Prussian blue layer, and a uricase layer stacked from bottom to top. The uricase layer comprises uricase, carbon nanotubes, and chitosan. The glucose sensing electrode comprises a second graphite carbon layer, a gold layer, a carbon nanotube layer, a second Prussian blue layer, and a glucose oxidase layer stacked from bottom to top. Compared to traditional sweat-based or other non-invasive biosensors that can only monitor a single analyte at a time, the dual-function sensor provided by this invention employs a four-electrode system, integrating the uric acid and glucose sensors, enabling simultaneous and selective measurement of sweat metabolites—uric acid and glucose—for multi-channel in-situ sweat analysis. The entire sensing process takes only one minute. By utilizing Prussian blue modification, the sensitivity of both bifunctional sensors in this invention is improved. Immobilizing uricase with carbon nanotubes and chitosan not only increases the electrode area but also ensures the activity of uricase. Gold and carbon nanotubes enhance the conductivity of the glucose working electrode, improving the electrode response of the glucose sensor. The sensitivities of the uric acid sensor and glucose sensor of this invention are 1.654 μA / mM and 0.383 μA / mM, respectively, with linear detection ranges of 0–2 mM and 0–10 mM, respectively, which can well cover their concentration range under physiological conditions. Furthermore, the selectivity of the bifunctional sensor of this invention is highly selective, maintaining the independent and selective operation of each individual sensor, which can fully meet industry needs.

[0029] Meanwhile, the dual-function sensor for simultaneous detection of uric acid and glucose provided by this invention is a flexible dual-function sensor belonging to the field of wearable sensors. Compared with traditional biosensors, this invention is not only smaller in size and suitable for wear, but also overcomes the problems of pain, invasiveness, and high cost associated with traditional sensors. Furthermore, this invention solves the problem of poor flexibility, achieving a close fit between the sensor and the skin, and has significant application value.

[0030] The preparation method provided by this invention adopts an integrated dual-function approach, fabricating uric acid and glucose sensors on a flexible substrate using printing technology. The two working electrodes and the counter electrode are formed by printing graphite carbon onto the flexible substrate, while the reference electrode is formed by printing Ag / AgCl ink onto the flexible substrate. This enables a stable sensor-skin contact, providing a low-cost, simple, convenient, and mass-producible method for sensor fabrication. This invention allows for the simultaneous and specific detection of uric acid and glucose without pricking the finger or causing invasiveness, improving the electrochemical performance of the sensor. It offers advantages such as high sensitivity and a wide linear detection range, enabling rapid and accurate detection and possessing practical application potential. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the electrode structure of the dual-function sensor for simultaneous detection of uric acid and glucose as described in this invention, wherein 1 is the uric acid sensing working electrode, 2 is the reference electrode, 3 is the counter electrode, and 4 is the glucose sensing working electrode.

[0033] Figure 2 This is a schematic diagram illustrating the fabrication process of the dual-function sensor for simultaneously detecting uric acid and glucose as described in this invention.

[0034] Figure 3 This is a schematic diagram of the structure of the uric acid sensing working electrode in the dual-function sensor of the present invention, wherein 1 is a graphite carbon layer, 2 is a Prussian blue layer, and 3 is a uricase / carbon nanotube / chitosan composite layer.

[0035] Figure 4 This is a schematic diagram of the glucose sensing working electrode in the dual-function sensor of the present invention, wherein 1 is a graphite carbon layer, 2 is a gold layer, 3 is a carbon nanotube layer, 4 is a Prussian blue layer, and 5 is a glucose oxidase layer.

[0036] Figure 5 This is a schematic diagram illustrating the working concept of the dual-function sensor described in this invention, based on the "contact-sensing" principle.

[0037] Figure 6 This is a schematic diagram of the in vitro detection experimental device for the dual-function sensor described in this invention, wherein 1 is the electrolyte, 2 is the dual-function sensor, and 3 is the electrochemical workstation.

[0038] Figure 7This is a working mechanism diagram of the uric acid sensor in the dual-function sensor described in this invention, wherein 1 is the graphite carbon layer, 2 is the Prussian blue layer, and 3 is the uricase / carbon nanotube / chitosan composite layer.

[0039] Figure 8 This is a comparison graph of cyclic voltammetry of the uric acid sensor in the dual-function sensor obtained in Example 1;

[0040] Figure 9 This is a working mechanism diagram of the glucose sensor in the dual-function sensor described in this invention, wherein 1 is a graphite carbon layer, 2 is a gold layer, 3 is a carbon nanotube layer, 4 is a Prussian blue layer, and 5 is a glucose oxidase layer.

[0041] Figure 10 This is a comparison graph of cyclic voltammetry of the glucose sensor in the dual-function sensor obtained in Example 1;

[0042] Figure 11 The graph shows the electrode response test results of the uric acid sensor in the dual-function sensor obtained in Example 1.

[0043] Figure 12 The graph shows the electrode response test results of the glucose sensor in the dual-function sensor obtained in Example 1.

[0044] Figure 13 The graph shows the selective test results of the uric acid sensor and glucose sensor in the dual-function sensor obtained in Example 1. Detailed Implementation

[0045] The present invention provides a dual-function sensor for simultaneously detecting uric acid and glucose, comprising a substrate and a uric acid sensing working electrode, a glucose sensing working electrode, a reference electrode, a counter electrode disposed on the substrate, an electrode interface of the above electrodes, and a conductive trace connecting the above electrodes and the electrode interface.

[0046] The uric acid sensing working electrode comprises a first graphite carbon layer, a first Prussian blue layer, and a uricase layer stacked from bottom to top; the uricase layer comprises uricase, carbon nanotubes, and chitosan.

[0047] The glucose sensing working electrode comprises, from bottom to top, a second graphite carbon layer, a gold layer, a carbon nanotube layer, a second Prussian blue layer, and a glucose oxidase layer.

[0048] In this invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

[0049] In this invention, the size of the dual-function sensor is preferably 125–200 mm. 2 More preferably, 130–160 mm 2 .

[0050] In this invention, the substrate surface preferably comprises, sequentially arranged, a uric acid sensing working electrode and its electrode interface and conductive trajectory, a reference electrode and its electrode interface and conductive trajectory, a counter electrode and its electrode interface and conductive trajectory, and a glucose sensing working electrode and its electrode interface and conductive trajectory; the conductive trajectories of the uric acid sensing working electrode, the reference electrode, and the glucose sensing working electrode preferably extend towards the counter electrode at right angles. The dual-function sensor electrode designed in this invention is easy to integrate and can be worn.

[0051] In this invention, the substrate is preferably a flexible substrate; the material of the flexible substrate is preferably polyethylene terephthalate or polyimide; the thickness of the substrate is preferably 0.012-0.025 mm, more preferably 0.015-0.02 mm.

[0052] In this invention, the uric acid sensing working electrode is preferably circular; the area of ​​the uric acid sensing working electrode is preferably 2.01–7.065 mm². 2 More preferably 3-5mm 2 The composition of the uricase layer preferably includes uricase, carbon nanotubes and chitosan; the mass ratio of uricase, carbon nanotubes and chitosan is preferably 5:2:10 to 42, more preferably 5:2:20 to 30.

[0053] In this invention, the glucose sensing working electrode is preferably circular; the area of ​​the glucose sensing working electrode is preferably 2.01–7.065 mm². 2 More preferably 3-5mm 2 The raw materials for the glucose oxidase layer preferably include glucose oxidase, glutaraldehyde, and bovine serum albumin; the mass ratio of glucose oxidase, glutaraldehyde, and bovine serum albumin is preferably 30-60:26:40, more preferably 40-50:26:40.

[0054] In this invention, the reference electrode is preferably an Ag / AgCl electrode; the ratio of silver to silver chloride is not particularly limited, and the ratio of silver to silver chloride in silver-silver chloride ink, which is well known to those skilled in the art, can be used; the reference electrode is preferably circular; the area of ​​the reference electrode is preferably 2.01–7.065 mm². 2 More preferably 3-5mm 2 .

[0055] In this invention, the counter electrode is preferably a graphite electrode; the counter electrode is preferably zigzag-shaped; the total length of the counter electrode is preferably 12-16 mm, more preferably 13-15 mm; the width is preferably 0.8-1.1 mm, more preferably 1 mm.

[0056] In this invention, the conductive trace width of the electrodes is preferably 0.3–0.8 mm, more preferably 0.4–0.6 mm; the conductive trace length of the uric acid sensing working electrode and the glucose sensing working electrode is preferably 8–9 mm, more preferably 8.5–9 mm; the conductive trace length of the counter electrode is preferably 2.5–3.5 mm, more preferably 3–3.5 mm; the conductive trace length of the reference electrode is preferably 3.5–4.5 mm, more preferably 4–4.5 mm; the conductive trace is preferably made of silver; the conductive trace also preferably includes an insulating layer on both sides; the width of the insulating layer is preferably 0.5–1 mm, more preferably 0.6–0.9 mm.

[0057] In this invention, the electrode interface is preferably rectangular in shape; its area is preferably 0.64–1.44 mm². 2 More preferably, it is 0.8–1.2 mm. 2 The preferred material for the electrode interface is silver.

[0058] The present invention also provides a method for fabricating the dual-function sensor described in the above technical solution, characterized by comprising the following steps:

[0059] Conductive traces and electrode interfaces of a uric acid sensing working electrode, a glucose sensing working electrode, a reference electrode, and a counter electrode are fabricated on the substrate surface.

[0060] The graphite carbon paste is screen-printed at the ends of the conductive traces of the uric acid sensing working electrode, the glucose sensing working electrode and the counter electrode to obtain a first graphite carbon layer, a second graphite carbon layer and a counter electrode.

[0061] A mixed solution of a first iron salt and ferricyanide is coated onto the surface of the first graphite carbon layer, followed by a first deposition and a first activation to obtain a first Prussian blue layer; a uricase solution is then coated onto the surface of the first Prussian blue layer to obtain a uricase layer, which is the uric acid sensing working electrode; the solute of the uricase solution includes uricase, carbon nanotubes and chitosan.

[0062] Metallographic deposition is performed on the surface of the second graphite carbon layer to obtain a gold layer; a carbon nanotube dispersion is coated on the surface of the gold layer to obtain a carbon nanotube layer; a mixed solution of a second iron salt and ferricyanide is coated on the surface of the carbon nanotube layer, and a second deposition and a second activation are performed sequentially to obtain a second Prussian blue layer; a glucose oxidase solution is coated on the surface of the second Prussian blue layer to obtain a glucose oxidase layer, which is the glucose sensing working electrode.

[0063] A second screen printing process is performed on the end of the conductive trace of the reference electrode using silver-silver chloride ink to obtain the reference electrode, thus obtaining the dual-function sensor.

[0064] The present invention prepares conductive traces and electrode interfaces for a uric acid sensing working electrode, a glucose sensing working electrode, a reference electrode, and a counter electrode on a substrate surface.

[0065] In this invention, the preparation of the conductive traces and electrode interfaces preferably includes cleaning the substrate; the cleaning preferably includes sequential aqueous and alcohol washing; the reagent for the aqueous washing is preferably deionized water; and the reagent for the alcohol washing is preferably anhydrous ethanol.

[0066] In this invention, the conductive traces and electrode interfaces are preferably prepared by printing; the printing material is preferably silver ink.

[0067] After obtaining the conductive traces and electrode interfaces, the present invention performs a first screen printing of graphite carbon slurry at the ends of the conductive traces of the uric acid sensing working electrode, the glucose sensing working electrode and the counter electrode to obtain a first graphite carbon layer, a second graphite carbon layer and a counter electrode.

[0068] In this invention, after the first screen printing, it is preferable to further include preparing an insulating layer on both sides of the conductive trace; the method of preparing the insulating layer is screen printing; the raw material for preparing the insulating layer is preferably insulating ink, more preferably UV-curable insulating ink.

[0069] After obtaining the first graphite carbon layer, the present invention coats the surface of the first graphite carbon layer with a mixed solution of the first iron salt and ferricyanide, and performs the first deposition and the first activation in sequence to obtain the first Prussian blue layer; then coats the surface of the first Prussian blue layer with a uricase solution to obtain the uricase layer, thus obtaining the uric acid sensing working electrode.

[0070] In this invention, the volume of the mixed solution of the first ferric salt and ferricyanide is preferably 80-120 μL, more preferably 100-120 μL; the ferric salt in the mixed solution of the first ferric salt and ferricyanide is preferably ferric chloride, with a concentration preferably 2-2.5 mM, more preferably 2.5 mM; the ferricyanide is preferably potassium ferricyanide, with a concentration preferably 2-2.5 mM, more preferably 2.5 mM; the solute in the mixed solution of the first ferric salt and ferricyanide also preferably includes hydrogen chloride and potassium chloride; the concentration of the hydrogen chloride is preferably 0.01-0.1 M, more preferably 0.05-0.1 M; the concentration of the potassium chloride is preferably 0.01-0.1 M, more preferably 0.05-0.1 M.

[0071] In this invention, the coating method is preferably dripping.

[0072] In this invention, the first deposition method is preferably electrodeposition, more preferably constant voltage in-situ electrodeposition; the voltage of the electrodeposition is preferably 0.4 to 0.8V, more preferably 0.4 to 0.6V; the time is preferably 60 to 120s, more preferably 80 to 100s.

[0073] In this invention, the first deposition is preferably followed by water washing; the water washing reagent is preferably deionized water.

[0074] In this invention, the first activating reagent is preferably a mixed solution of hydrogen chloride and chloride salt; the concentration of hydrogen chloride in the mixed solution of hydrogen chloride and chloride salt is preferably 0.01-0.1M, more preferably 0.05-0.1M; the chloride salt in the mixed solution of hydrogen chloride and chloride salt is preferably potassium chloride; the concentration is preferably 0.01-0.1M, more preferably 0.05-0.1M; the amount of the first activating reagent is preferably 80-120μL, more preferably 100-120μL; the first activation is preferably performed by cyclic voltammetry; the voltage of the cyclic voltammetry is preferably -0.2-0.6V, more preferably -0.2-0.4V, and most preferably -0.1-0.35V; the scan rate is preferably 50-100mV / s, more preferably 50-80mV / s; the number of cycles is preferably 18-24 times, more preferably 20-22 times.

[0075] In this invention, the volume of the uricase solution is preferably 3-6 μL, more preferably 4 μL; the solute of the uricase solution preferably includes uricase, carbon nanotubes, and chitosan; the carbon nanotubes are preferably multi-walled carbon nanotubes; the mass ratio of uricase, carbon nanotubes, and chitosan is preferably 5:2:10-42, more preferably 5:2:20-30; the concentration of uricase in the uricase solution is preferably 1.5-2.5 mg / mL, more preferably 1.5-2 mg / mL; the solute of the uricase solution also preferably includes glacial acetic acid; the mass ratio of glacial acetic acid to chitosan is preferably 1:1-2, more preferably 1:1.5-2; the preferred method for preparing the uricase solution is: carbon nanotubes-glacial acetic acid... The uricase solution is obtained by mixing the carbon nanotube-chitosan solution and the urase phosphate buffer solution. The concentration of carbon nanotubes in the carbon nanotube-acetic acid-chitosan solution is preferably 1-2 mg / mL, more preferably 1.5-2 mg / mL. The mass percentage of acetic acid is preferably 1-1.5%, more preferably 1%. The mass percentage of chitosan is preferably 1-2%, more preferably 1.5-2%. The concentration of uricase in the urase phosphate buffer solution is preferably 1.5-2.5 mg / mL, more preferably 2-2.5 mg / mL. The volume ratio of the carbon nanotube-acetic acid-chitosan solution to the uricase phosphate buffer solution is preferably 1:1-2, more preferably 1:1.5-2.

[0076] In this invention, after coating with the uricase solution, it is preferable to allow the mixture to stand, preferably at a temperature of 4°C for 24 hours.

[0077] After obtaining the second graphite carbon layer, the present invention performs metallographic deposition on the surface of the second graphite carbon layer to obtain a gold layer; a carbon nanotube dispersion is coated on the surface of the gold layer to obtain a carbon nanotube layer; a mixed solution of a second iron salt and ferricyanide is coated on the surface of the carbon nanotube layer, and a second deposition and a second activation are performed sequentially to obtain a second Prussian blue layer; a glucose oxidase solution is coated on the surface of the second Prussian blue layer to obtain a glucose oxidase layer, thus obtaining a glucose sensing working electrode.

[0078] In this invention, the metallographic deposition method is preferably magnetron sputtering.

[0079] In this invention, the volume of the carbon nanotube dispersion is preferably 3-4 μL, more preferably 3 μL; the carbon nanotubes in the carbon nanotube dispersion are preferably multi-walled carbon nanotubes; the concentration of carbon nanotubes in the carbon nanotube dispersion is preferably 0.5-1 mg / mL, more preferably 0.5-0.8 mg / mL; the solute in the carbon nanotube dispersion also preferably includes perfluorosulfonic acid, with a mass percentage preferably of 1.5-2.5%, more preferably 2-2.5%.

[0080] In this invention, the volume of the mixed solution of the second ferric salt and ferricyanide is preferably 80-120 μL, more preferably 100-120 μL; the ferric salt in the mixed solution of the second ferric salt and ferricyanide is preferably ferric chloride, with a concentration preferably 2-2.5 mM, more preferably 2.5 mM; the ferricyanide is preferably potassium ferricyanide, with a concentration preferably 2-2.5 mM, more preferably 2.5 mM; the solute in the mixed solution of the second ferric salt and ferricyanide also preferably includes hydrogen chloride and potassium chloride; the concentration of the hydrogen chloride is preferably 0.01-0.1 M, more preferably 0.05-0.1 M; the concentration of the potassium chloride is preferably 0.01-0.1 M, more preferably 0.05-0.1 M.

[0081] In this invention, the coating method is preferably dripping.

[0082] In this invention, the second deposition method is preferably electrodeposition, more preferably constant voltage in-situ electrodeposition; the electrodeposition voltage is preferably 0.4-0.8V, more preferably 0.6-0.8V; the time is preferably 60-120s, more preferably 100-120s.

[0083] In this invention, the second activating reagent is preferably a mixed solution of hydrogen chloride and chloride salt; the concentration of hydrogen chloride in the mixed solution of hydrogen chloride and chloride salt is preferably 0.01-0.1M, more preferably 0.05-0.1M; the chloride salt in the mixed solution of hydrogen chloride and chloride salt is preferably potassium chloride; the concentration is preferably 0.01-0.1M, more preferably 0.05-0.1M; the amount of the second activating reagent is preferably 80-120μL, more preferably 100-120μL; the second activation is preferably performed by cyclic voltammetry; the voltage of the cyclic voltammetry is preferably -0.2-0.6V, more preferably -0.3-0.6V, and most preferably -0.2-0.5V; the scan rate is preferably 50-100mV / s, more preferably 50-80mV / s; the number of cycles is preferably 18-24 times, more preferably 20-22 times.

[0084] In this invention, the volume of the glucose oxidase solution is preferably 3-6 μL, more preferably 4 μL; the solute in the glucose oxidase solution preferably includes glucose oxidase, glutaraldehyde, and bovine serum albumin; the mass ratio of glucose oxidase, glutaraldehyde, and bovine serum albumin is preferably 30-60:26:40, more preferably 40-50:26:40; the concentration of glucose oxidase in the glucose oxidase solution is preferably 30-60 mg / mL, more preferably 40-50 mg / mL. This invention utilizes the chemical reaction between glutaraldehyde and bovine serum albumin to immobilize glucose oxidase on the electrode surface.

[0085] In this invention, after coating the glucose oxidase solution, it is preferable to allow the mixture to stand, preferably at a temperature of 4°C for a time of 24 hours.

[0086] After obtaining the conductive trace and electrode interface, the present invention performs a second screen printing of silver-silver chloride ink at the end of the conductive trace of the reference electrode to obtain the reference electrode and thus obtain the dual-function sensor.

[0087] The present invention does not impose any special limitations on the thickness of the uric acid sensing working electrode, glucose sensing working electrode, reference electrode, counter electrode, electrode interface of the above electrodes, and conductive trace connecting the above electrodes and electrode interface. The preparation method described in the above technical solution can be used to make the above components have the conventional thickness corresponding to each step of the operation.

[0088] The present invention also provides the application of the dual-function sensor described in the above technical solution or the dual-function sensor prepared by the preparation method described in the above technical solution in the preparation of wearable products.

[0089] The present invention does not impose any special restrictions on the application process of the dual-function sensor in the manufacture of wearable products; any process known to those skilled in the art can be used.

[0090] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, describes the dual-function sensor for simultaneous detection of uric acid and glucose, its preparation method, and its application, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0091] Example 1

[0092] To simultaneously detect two analytes (uric acid and glucose) in a single sample, enabling wearable technology, improved sensor sensitivity, reduced costs, and mass production, this embodiment provides a flexible bifunctional sensor for the simultaneous detection of uric acid and glucose, along with its fabrication method. A schematic diagram of the electrode structure of the flexible bifunctional sensor for the simultaneous detection of uric acid and glucose provided in this embodiment is shown below. Figure 1 Among them, 1 is the uric acid sensing working electrode, 2 is the reference electrode, 3 is the counter electrode, and 4 is the glucose sensing working electrode.

[0093] Depend on Figure 1 As can be seen, this invention designs and constructs a novel dual-working-electrode electrochemical sensing system for the simultaneous determination of uric acid and glucose. The sensor's planar electrodes are fabricated on a flexible PET substrate using screen printing technology. The sensor employs a four-electrode system. Working electrode 1 is the working electrode for the uric acid sensor, working electrode 4 is the working electrode for the glucose sensor, and reference electrode 2 and counter electrode 3 serve as shared reference and counter electrodes for both sensors. Uric acid and glucose are detected using cyclic voltammetry and time-current method. The overall dimensions of the planar electrode of this dual-function sensor are 12mm × 11mm.

[0094] The method for fabricating a dual-functional sensor provided in this embodiment includes the following steps:

[0095] Step 1: The planar electrode of the flexible dual-function sensor in this embodiment is fabricated using screen printing technology, with the base material being flexible PET with a thickness of 0.018 mm. A schematic diagram of the fabrication process for the screen-printed sensor electrode in this embodiment can be found here. Figure 2 .Depend on Figure 2 As can be seen, firstly, the substrate is cleaned with distilled water, and then cleaned with anhydrous ethanol to obtain a clean, impurity-free PET substrate 1. Then, conductive traces of the working electrode 1, reference electrode 2, counter electrode 3, and working electrode 4, as well as the electrode interface 5, are printed using silver ink. The conductive trace width of each electrode is 0.5 mm, the conductive trace length of the uric acid sensing working electrode and the glucose sensing working electrode is 8.5 mm, the conductive trace length of the counter electrode is 3 mm, the conductive trace length of the reference electrode is 4.5 mm, and the electrode interface has an area of ​​1 mm². 2A rectangular shape is used to obtain planar electrode 2. Graphite carbon is used for screen printing counter electrode 3, which has a thickened zigzag design. If the thickened line is straightened, its dimensions are 14mm × 1mm, thus obtaining planar electrode 3. Working electrode 1 and working electrode 4 are also made using graphite carbon screen printing, both of which are circular with a diameter of 2mm, thus obtaining planar electrode 4. UV-curable insulating ink is used to screen print insulating layers on both sides of the conductive trace, which are rectangular in shape and 0.7mm wide, thus obtaining planar electrode 5. Reference electrode 2 is screen printed using Ag / AgCl ink, and is circular in shape with a diameter of 2mm. Thus, the complete planar electrode 6 of the flexible dual-function sensor is obtained. The area of ​​the working electrode is approximately 3.14mm². 2 The area of ​​the overall planar electrode is approximately 132 mm². 2 The planar electrode has a small area, meeting the requirements for wearable devices, and at the same time solves the problem of poor sensor flexibility in existing technologies, achieving stable contact between the sensor and the skin.

[0096] Step 2: The present invention provides a schematic diagram of the structure of the working electrode of the uric acid sensor (see attached diagram). Figure 3 .Depend on Figure 3As can be seen, the uric acid sensing working electrode is configured from bottom to top as a graphite carbon layer 1, a Prussian blue layer 2, and a uricase / carbon nanotube / chitosan composite layer 3. The working electrode of the uric acid sensor is modified using the following steps: First, Prussian blue is electrodeposited onto the working electrode using a constant potential electrodeposition method. Working electrode 1 serves as the working electrode of the uric acid sensor, while reference electrode 2 and counter electrode 3 serve as the reference and counter electrodes, respectively. 120 μL of a solution containing 2.5 mM FeCl3, 2.5 mM K3Fe(CN)6, 0.1 M HCl, and 0.1 M KCl is dripped onto the graphite carbon layer 1 of the working electrode, and a bias voltage of 0.4 V is applied for 100 s. After rinsing with deionized water, 120 μL of a solution of 0.1 M HCl and 0.1 M KCl was used to cover the prepared Prussian blue layer 2. Activation was performed using cyclic voltammetry at a scan rate of 50 mV / s within the range of -0.1 to 0.35 V for 20 cycles to obtain the activated Prussian blue layer 2. Next, a uricase / carbon nanotube / chitosan composite material was prepared. 2 mg of multi-walled carbon nanotubes were uniformly dispersed in 1 mL of a solution containing 1 wt% glacial acetic acid and 2 wt% chitosan to prepare a 2 mg / mL carbon nanotube composite solution. Uricase was then dissolved in phosphate buffer to prepare a 2.5 mg / mL uricase solution. Finally, these two solutions were mixed at a volume ratio of 1:2 to prepare the uricase / carbon nanotube / chitosan composite material. Finally, 4 μL of uricase / carbon nanotube / chitosan was dripped onto the Prussian blue layer 2 and stored at 4 °C for drying overnight to obtain the uricase / carbon nanotube / chitosan composite layer 3. This invention uses a Prussian blue layer 2 and a uricase / carbon nanotube / chitosan composite layer 3 to modify the working electrode of the uric acid sensor, which significantly improves the electron transfer efficiency and electron conduction capability of the electrode, increases the redox current of the sensor, and improves the sensitivity of the sensor in detecting uric acid.

[0097] Step 3: The present invention provides a schematic diagram of the structure of the working electrode of the glucose sensor (see attached diagram). Figure 4 .Depend on Figure 4As can be seen, the working electrode of the glucose sensor consists of a graphite carbon layer 1, a gold layer 2, a multi-walled carbon nanotube layer 3, a Prussian blue layer 4, and a glucose oxidase layer 5. The working electrode of the glucose sensor was modified using the following steps: First, a 200 nm thick Au layer 2 was sputtered onto the graphite carbon layer 1 using magnetron sputtering. Next, 1 mg of carboxylated multi-walled carbon nanotubes were dispersed in 2 mL of 2 wt% Nafion solution to prepare a 0.5 mg / mL multi-walled carbon nanotube / Nafion composite solution. Then, 3 μL of the multi-walled carbon nanotube / Nafion composite solution was dropped onto the gold layer 2 to obtain the multi-walled carbon nanotube layer 3. Then, using the electrode modified with gold layer 2 and multi-walled carbon nanotube layer 3 as the working electrode, and reference electrode 2 and counter electrode 3 as the reference and counter electrodes of the glucose sensor, Prussian blue was electrodeposited in situ at a constant voltage of 0.8 V in a mixed solution of 2.5 mM FeCl3, 2.5 mM K3Fe(CN)6, 0.1 M HCl, and 0.1 M KCl for 100 s. Then, 120 μL of a mixed solution of 0.1 M HCl and 0.1 M KCl was used to cover the electrodeposited Prussian blue layer. Prussian blue layer 4 was then activated in a mixed solution of 0.1 M HCl and 0.1 M KCl using cyclic voltammetry, with a potential range of -0.2 to 0.5 V, a scan rate of 50 mV / s, and 20 cycles. Finally, 4 μL of a mixed solution of glucose oxidase / bovine serum albumin / glutaraldehyde was added dropwise onto the Prussian blue layer 4. The glucose oxidase concentration was 50 mg / mL, the bovine serum albumin concentration was 40 mg / mL, and the glutaraldehyde concentration was 2.5%. The solvent was phosphate buffer. The glucose oxidase was immobilized on the Prussian blue layer 4 via a chemical cross-linking reaction of glutaraldehyde, bovine serum albumin, and glucose oxidase. The layer was then dried overnight at 4°C to obtain a stable glucose oxidase layer 5. The working electrode of this glucose sensor, modified with gold, multi-walled carbon nanotubes, and Prussian blue, exhibits improved biocompatibility, enhanced conductivity, and increased stability and activity of glucose oxidase, thus meeting the requirements for improving the sensitivity of the glucose sensor and broadening the linear detection range. A schematic diagram of the resulting dual-function sensor based on the "contact-sensing" working concept is shown below. Figure 5 .

[0098] Depend on Figure 5 As can be seen, the sensor manufactured in this embodiment is flexible and can be bent to fit the skin, meeting the requirements for wearable devices. Without pricking fingers or causing any invasiveness, the sensor comes into contact with sweat on the skin's surface to simultaneously and selectively test uric acid and glucose in the sweat. The entire sensing process takes only one minute.

[0099] Test Example 1

[0100] This invention employs a dual-working-electrode system to construct a dual-functional sensor. A schematic diagram of the in vitro detection experimental setup for the dual-functional sensor is shown below. Figure 6 In this method, phosphate buffer solution is used as electrolyte 1. The operating voltages of the uric acid sensor and glucose sensor are determined by cyclic voltammetry. An electrochemical workstation 3 provides the operating voltage to the dual-function sensor 2, and the uric acid sensor and glucose sensor generate current signals after an electrochemical reaction. The dual-function sensor provided by this invention can simultaneously and selectively measure uric acid and glucose, and can be used for in-situ multichannel sweat analysis, achieving non-invasive, wearable detection. The working mechanism diagram and cyclic voltammetry comparison diagram of the uric acid sensor and the glucose sensor provided by this invention are shown below. Figures 7-10 .

[0101] Depend on Figure 7 As can be seen, the working electrode of the uric acid sensor comprises a graphite carbon layer 1, a Prussian blue layer 2, and a uricase / carbon nanotube / chitosan composite layer 3, arranged sequentially. The Prussian blue layer 2 acts as a redox medium, improving electron transfer between electrodes and reducing the reduction potential. Chitosan, a natural polymer, possesses excellent film-forming ability, biocompatibility, and non-toxicity, serving as the immobilization matrix for uricase in this invention. Carbon nanotubes increase the electrode area, thereby increasing the bilayer capacitance. Under the action of uricase, uric acid is oxidized on the carbon electrode modified with the Prussian blue layer 2 and the uricase / carbon nanotube / chitosan composite layer 3, generating allantoin while simultaneously producing carbon dioxide and hydrogen peroxide. Hydrogen peroxide is reduced to water under the action of Prussian blue and releases an electron. This electron is transferred to the electrode, causing a change in current, thus achieving uric acid detection. Within a certain uric acid concentration range, the sensing response exhibits linearity.

[0102] Depend on Figure 8 As shown in the cyclic voltammetry comparison diagram of the uric acid sensor of this invention, the electrochemical oxidation peak potential of the unmodified bare carbon electrode is 0.2V, while that of the Prussian blue, uricase / carbon nanotube / chitosan-modified carbon electrode is 0.1V. Simultaneously, the peak current of the oxidation peak corresponding to the Prussian blue, uricase / carbon nanotube / chitosan-modified carbon electrode is 2.87 times that of the bare carbon electrode. Modifying the bare carbon electrode with Prussian blue layer 2 and uricase / carbon nanotube / chitosan composite layer 3 reduces the peak potential of the oxidation peak of the uric acid sensor and increases the response current, thereby improving the electrochemical catalytic oxidation performance of the uric acid sensor and achieving high sensitivity and accurate detection of uric acid levels.

[0103] Depend on Figure 9As can be seen, the working electrode of the glucose sensor, from bottom to top, is composed of a graphite carbon layer 1, a gold layer 2, a multi-walled carbon nanotube layer 3, a Prussian blue layer 4, and a glucose oxidase layer 5. The gold layer 2 is directly grown on the bare carbon electrode, improving the electrode's biocompatibility and conductivity. The carboxylated multi-walled carbon nanotube layer 3 enhances the adsorption of the electrode surface through carboxyl groups, improving electrochemical detection performance. The Prussian blue layer 4 acts as an electron medium, selectively detecting H2O2 in the presence of oxidation and other interfering substances. Prussian blue catalyzes the reduction of H2O2 at low potentials. In the presence of the glucose oxidase layer 5, glucose in electrolyte 1 is selectively oxidized to gluconic acid and H2O2. Hydrogen peroxide undergoes a reduction reaction under the action of Prussian blue, releasing electrons that pass through the conductor and generate an electrical response. The glucose concentration can be identified by the current response.

[0104] Depend on Figure 10 The diagram shows a cyclic voltammetry comparison of the glucose sensor of this invention. The oxidation peak currents of the gold, multi-walled carbon nanotube, and Prussian blue-modified carbon electrodes are 6.16 times and 9.89 times that of the Prussian blue-modified, multi-walled carbon nanotube, and Prussian blue-modified electrodes, respectively. Meanwhile, the oxidation peak potentials of the glucose sensors modified with gold, multi-walled carbon nanotubes, and Prussian blue are 0.1 V. This invention utilizes the high charge transfer characteristics of gold, multi-walled carbon nanotubes, and Prussian blue to construct a glucose sensor with high sensitivity and selectivity.

[0105] Test Example 2

[0106] In the in vitro electrochemical detection using dual-function sensors, the working electrode, reference electrode, and counter electrode are connected to an electrochemical workstation. First, the operating potential of both the uric acid and glucose sensors is determined to be 0.1V (relative to the reference electrode) using cyclic voltammetry. Then, a constant potential control method is used to provide the operating voltage to the uric acid and glucose sensors. Upon application of the voltage, an electrochemical reaction occurs, generating a response current.

[0107] Under the action of uricase, uric acid is specifically oxidized to allantoin, and two electrons are transferred to generate a sensing current. Similarly, glucose is oxidized to H₂O₂ and gluconic acid under the action of glucose oxidase. H₂O₂, acting as an oxidant, releases free electrons that pass through the conductor, generating an electrical response. Both uric acid and glucose concentrations are identified through current response. The test results of the uric acid sensor and glucose sensor of this invention are shown in the figure below. Figures 11-12 .

[0108] Depend on Figure 11The image shows the test results of the uric acid sensor of this invention. The prepared flexible dual-function sensor was immersed in buffer solutions containing different concentrations of uric acid, and the test was performed using a current-time method. The operating voltage of the uric acid sensor was set to 0.1V, and after power-on for 60 seconds, the sensitivity, linear detection range, and linearity of the uric acid sensor were evaluated. Further analysis showed that the uric acid sensor in this invention has a sensitivity of 1.654 μA / mM, a linear detection range of 0–2 mM, and a linearity of 0.998. Therefore, the uric acid sensor manufactured in this invention exhibits a wide electrode response range and good linearity.

[0109] Depend on Figure 12 As can be seen, this is a graph showing the test results of the glucose sensor of the present invention. Figure 1 This is a schematic diagram of the system data transmission structure. Assuming the glucose sensor operates at 0.1V, the bifunctional sensor prepared according to this invention is immersed in a buffer solution, to which a rotor is added. A glucose solution of a certain concentration is injected every 25 seconds, increasing the glucose concentration by 0.8mM. Under suitable conditions, the glucose sensor of this invention has a sensitivity of 0.383μA / mM, a linear detection range of 0–10mM, and a linearity of 0.993. One of the bifunctional sensors of this invention, the glucose sensor, exhibits high sensitivity and a wide linear detection range.

[0110] As can be seen from the above, under physiological conditions, the concentration ranges of uric acid and glucose in sweat are 24.5–35.7 μM and 0.01–1.11 mM, respectively. The linear detection ranges of the dual-function sensor of this invention are 0–2 mM and 0–10 mM, respectively, which can well cover the concentration ranges under physiological conditions, further demonstrating the feasibility of this dual-function sensor in detecting real samples.

[0111] Test Example 3

[0112] Selectivity tests were performed on the uric acid and glucose sensors of this invention. The operating voltage was applied using an electrochemical workstation, and the 60-second current-time method was used for evaluation. Common interferences at their respective physiological concentration levels were added to the sensors, such as 50 μM uric acid (for glucose sensing), 1 mM glucose (for uric acid sensing), 5 μM lactate, and 10 μM ascorbic acid. Results are shown below. Figure 13 .

[0113] Depend on Figure 13 As can be seen, the results show that the sensor exhibits specific responses to its targets, uric acid and glucose. These results demonstrate that the dual-function sensor of this invention has excellent selective detection results, enabling simultaneous and selective detection of uric acid and glucose.

[0114] As demonstrated by the above embodiments, the flexible dual-function sensor for simultaneous detection of uric acid and glucose provided by this invention enables multi-channel in-situ sweat analysis. It not only measures uric acid and glucose simultaneously but also maintains the independent and selective operation of each individual sensor. It not only establishes stable sensor-skin contact but also meets the requirements of small area and wearability. Furthermore, it reduces the operating potential of both the uric acid and glucose sensors, improves sensor sensitivity, and broadens the linear detection range. This invention develops a wearable sensor that is simple to fabricate, low in cost, highly sensitive, and accurate.

[0115] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A dual-function sensor for simultaneously detecting uric acid and glucose, characterized in that, It includes a substrate and a uric acid sensing working electrode, a glucose sensing working electrode, a reference electrode, a counter electrode, electrode interfaces of the above electrodes, and conductive traces connecting the above electrodes and electrode interfaces disposed on the substrate. The uric acid sensing working electrode comprises a first graphite carbon layer, a first Prussian blue layer, and a uricase layer stacked from bottom to top; the uricase layer is composed of uricase, carbon nanotubes, and chitosan; the mass ratio of uricase, carbon nanotubes, and chitosan is 5:2:10~42. The glucose sensing working electrode comprises, from bottom to top, a second graphite carbon layer, a gold layer, a carbon nanotube layer, a second Prussian blue layer, and a glucose oxidase layer; The raw materials for the glucose oxidase layer include glucose oxidase, glutaraldehyde, and bovine serum albumin. The mass ratio of glucose oxidase, glutaraldehyde, and bovine serum albumin is 30-60:26:

40. The linear detection range of the uric acid sensing working electrode is 0~2mM; The linear detection range of the glucose sensing working electrode is 0~10mM; The dual-function sensor is used to test uric acid and glucose in sweat; The electrochemical oxidation peak potential of the uric acid sensing working electrode is 0.1V; The electrochemical oxidation peak potential of the glucose sensing working electrode is 0.1V; The uric acid sensing working electrode and the glucose sensing working electrode are disposed on both sides of the counter electrode; The counter electrode is zigzag-shaped.

2. The dual-function sensor according to claim 1, characterized in that, The substrate is a flexible substrate; the size of the dual-function sensor is 125~200mm. 2 ; The substrate surface is sequentially provided with a uric acid sensing working electrode and its electrode interface and conductive trajectory, a reference electrode and its electrode interface and conductive trajectory, a counter electrode and its electrode interface and conductive trajectory, and a glucose sensing working electrode and its electrode interface and conductive trajectory; the conductive trajectories of the uric acid sensing working electrode, the reference electrode, and the glucose sensing working electrode all extend towards the counter electrode at right angles.

3. The dual-function sensor according to claim 1, characterized in that, The uric acid sensing working electrode is circular; the area of ​​the uric acid sensing working electrode is 2.01~7.065 mm². 2 .

4. The dual-function sensor according to claim 1, characterized in that, The glucose sensing working electrode is circular; the area of ​​the glucose sensing working electrode is 2.01~7.065 mm². 2 .

5. The dual-function sensor according to claim 1, characterized in that, The reference electrode is an Ag / AgCl electrode; the reference electrode is circular; the area of ​​the reference electrode is 2.01~7.065 mm². 2 ; The counter electrode is a graphite electrode; the total length of the counter electrode is 12~16mm and the width is 0.8~1.1mm.

6. A method for preparing the dual-function sensor according to any one of claims 1 to 5, characterized in that, Includes the following steps: Conductive traces and electrode interfaces of a uric acid sensing working electrode, a glucose sensing working electrode, a reference electrode, and a counter electrode are fabricated on the substrate surface. The graphite carbon paste is screen-printed at the ends of the conductive traces of the uric acid sensing working electrode, the glucose sensing working electrode and the counter electrode to obtain a first graphite carbon layer, a second graphite carbon layer and a counter electrode. A mixed solution of a first iron salt and ferricyanide is coated onto the surface of the first graphite carbon layer, followed by a first deposition and a first activation to obtain a first Prussian blue layer; a uricase solution is then coated onto the surface of the first Prussian blue layer to obtain a uricase layer, which is the uric acid sensing working electrode; the solute of the uricase solution includes uricase, carbon nanotubes and chitosan. Metallographic deposition is performed on the surface of the second graphite carbon layer to obtain a gold layer; a carbon nanotube dispersion is coated on the surface of the gold layer to obtain a carbon nanotube layer; a mixed solution of a second iron salt and ferricyanide is coated on the surface of the carbon nanotube layer, and a second deposition and a second activation are performed sequentially to obtain a second Prussian blue layer; a glucose oxidase solution is coated on the surface of the second Prussian blue layer to obtain a glucose oxidase layer, which is the glucose sensing working electrode. A second screen printing process is performed on the end of the conductive trace of the reference electrode using silver-silver chloride ink to obtain the reference electrode, thereby obtaining the dual-function sensor. The mass ratio of uricase, carbon nanotubes and chitosan is 5:2:10~42; The solutes in the glucose oxidase solution include glucose oxidase, glutaraldehyde, and bovine serum albumin; the mass ratio of glucose oxidase, glutaraldehyde, and bovine serum albumin is 30-60:26:

40.

7. The preparation method according to claim 6, characterized in that, The first and second depositions are independently electrodepositions; the electrodeposition voltage is 0.4~0.8V and the time is 60~120s.

8. The preparation method according to claim 6, characterized in that, The reagents for the first and second activations are independently a mixed solution of hydrogen chloride and chloride salt; the first and second activations are independently performed using cyclic voltammetry; the voltage of the cyclic voltammetry is -0.2 to 0.6 V, the scan rate is 50 to 100 mV / s, and the number of cycles is 18 to 24.

9. The application of the dual-function sensor according to any one of claims 1 to 5 or the dual-function sensor prepared by the preparation method according to any one of claims 6 to 8 in the preparation of wearable products.

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