Difunctional noble metal-nickel metal aerogel, wearable sweat bimodal enzyme-free glucose sensor as well as preparation method and application of wearable sweat bimodal enzyme-free glucose sensor

Abstract

The invention discloses difunctional noble metal-nickel metal aerogel, a wearable sweat bimodal enzyme-free glucose sensor as well as a preparation method and application of the wearable sweat bimodal enzyme-free glucose sensor, and relates to the technical field of metal aerogel. The method comprises the following steps: firstly, preparing high-sensitivity and high-selectivity noble metal-nickel-based dual-structure aerogel as a sensitive material, further preparing an electrochemical and colorimetric detection chip, and assembling the detection chip and a microfluidic device into wearable equipment. The dual-mode enzyme-free detection of the glucose in the sweat by an electrochemical method and a colorimetric method is realized.

Description

Technical Field

[0001] This invention relates to the field of metal aerogel technology, specifically to a dual-functional noble metal-nickel aerogel, a wearable sweat dual-modal enzyme-free glucose sensor, its preparation method, and its application. Background Technology

[0002] Glucose is an essential substance for energy metabolism in human cells, serving multiple physiological functions such as providing energy, maintaining nervous system function, and enhancing immunity. Diabetes is a chronic metabolic disease characterized by high blood sugar, often causing chronic damage and dysfunction of tissues such as the kidneys, heart, blood vessels, and nerves. Real-time blood glucose monitoring systems provide continuous blood glucose data, allowing users to understand the trend and fluctuation range of blood glucose levels in real time. This is especially important for diabetic patients, enabling them to monitor blood glucose levels promptly and adjust their diet, medication, or insulin treatment plans as needed.

[0003] Existing glucose sensors are mainly finger-prick blood glucose meters or semi-implantable continuous glucose monitoring sensors, used to effectively detect glucose concentration. However, existing detection devices have the following problems: 1) The detection process may cause pain and pose a potential risk of infection, making it difficult to achieve continuous monitoring in daily life; 2) Most commercial glucose sensors rely on biological enzymes as catalysts, which limits the sensor's usage conditions and stability; 3) Most glucose sensors use single-modal sensing methods such as electrochemical or colorimetric sensing, which poses risks such as numerical errors.

[0004] Wearable sweat glucose sensors utilize microfluidic devices to non-invasively collect sweat and convert its glucose concentration into a directly identifiable signal, indirectly reflecting the body's glucose levels, thus possessing broad application prospects. Inorganic catalytic materials can replace biological enzymes as glucose-sensitive materials, maintaining high sensor sensitivity and significantly improving sensor stability. Employing an electrochemical-colorimetric dual-modal detection approach enables in-situ real-time monitoring of sweat glucose in complex environments, reducing errors and improving detection accuracy. Summary of the Invention

[0005] To address the shortcomings of the aforementioned background technologies, this invention primarily solves the technical problems of accuracy and reliability in wound sampling and detection of existing commercial glucose detection methods. This invention provides a dual-functional noble metal-nickel aerogel, a wearable sweat dual-modal enzyme-free glucose sensor, its preparation method, and its applications. The method includes the preparation and modification of sensitive materials, the design and fabrication of the PDMS flow channel layer, and the assembly of the sensor. Innovative material design and process optimization enable this sensor to accurately monitor sweat glucose concentration and exhibit excellent long-term stability and anti-interference capabilities in practical applications. This technology provides an effective and reliable solution for precise human health monitoring.

[0006] The first objective of this invention is to provide a noble metal-nickel metal aerogel, including PtNi aerogel or AuNiFe aerogel; The PtNi aerogel is prepared by reacting a mixed solution of H2PtCl6 and NiCl2 with a NaBH4 solution and then freeze-drying it; the AuNiFe aerogel is prepared by reacting a mixed solution of HAuCl4, NiCl2 and FeCl3 with a NaBH4 solution and then freeze-drying it.

[0007] Preferably, the molar ratio of the mixed solution of H2PtCl6 and NiCl2 to the NaBH4 solution is 1:1~40; The mass fraction of H2PtCl6 in the mixed solution of H2PtCl6 and NiCl2 is 10 wt%. The molar ratio of H2PtCl6 to NiCl2 in the mixed solution of H2PtCl6 and NiCl2 is 1:0.1~6.

[0008] Preferably, the molar ratio of the mixed solution of HAuCl4, NiCl2 and FeCl3 to the NaBH4 solution is 1:1 to 40; The mass fraction of HAuCl4 in the mixed solution of HAuCl4, NiCl2, and FeCl3 is 10 wt%. The molar ratio of HAuCl4, NiCl2, and FeCl3 in the mixed solution is 1:0.1~6:0.01~2.

[0009] Preferably, the duration of the mixed reaction is 6-24 h.

[0010] The second objective of this invention is to provide an application of a precious metal-nickel metal aerogel in a wearable sweat-based dual-modal enzyme-free glucose sensor.

[0011] The third objective of this invention is to provide a wearable sweat-modal enzyme-free glucose sensor based on a dual-functional noble metal-nickel metal aerogel, comprising a PDMS flow channel layer stacked together and a capping layer covering the PDMS flow channel layer. The PDMS flow channel layer is provided with multiple liquid inlets, as well as a first liquid storage chamber and a second liquid storage chamber; the first liquid storage chamber and the second liquid storage chamber are connected by a first channel; each liquid inlet is connected to the first liquid storage chamber by a second channel; the second liquid storage chamber is also provided with an outlet; the capping layer is provided with through holes corresponding to each liquid inlet; An electrochemical detection chip is disposed in the first liquid storage chamber; a colorimetric detection chip is disposed in the second liquid storage chamber; the electrochemical detection chip is made of PtNi aerogel; and the colorimetric detection chip is made of AuNiFe aerogel.

[0012] Preferably, the electrochemical detection chip is prepared according to the following steps: preparing a dispersion containing PtNi aerogel, Nafion perfluorinated resin and ultrapure water; drop-coating the dispersion onto the surface of the working electrode of the screen-printed electrode and drying it under an infrared baking lamp to obtain the electrochemical detection chip after drying.

[0013] Preferably, the colorimetric detection chip is prepared according to the following steps: preparing a dispersion containing AuNiFe aerogel and a dispersion containing 3,3',5,5'-tetramethylbenzidine; A dispersion containing AuNiFe aerogel was applied to the surface of a filter paper and dried under an infrared baking lamp. After drying, a dispersion containing 3,3',5,5'-tetramethylbenzidine was added, and after drying, a colorimetric detection chip was obtained.

[0014] The fourth objective of this invention is to provide a method for preparing a wearable sweat-based dual-modal enzyme-free glucose sensor based on a bifunctional noble metal-nickel aerogel, comprising: Design the structure of the PDMS flow channel layer and fabricate the mold using photolithography; A PDMS flow channel layer with channels and a liquid storage cavity was prepared by molding, and multiple liquid inlets were processed at specific locations of the PDMS flow channel layer using a punch to obtain the PDMS flow channel layer. The top surface of the PDMS flow channel layer and the bottom surface of the capping layer are treated with oxygen plasma in a plasma processor. Then, the PDMS flow channel layer, electrochemical detection chip, colorimetric detection chip, and capping layer are immediately bonded and packaged to obtain a wearable sweat dual-modal enzyme-free glucose sensor based on a dual-functional noble metal-nickel metal aerogel.

[0015] The fifth objective of this invention is to provide an application of a wearable sweat dual-modal enzyme-free glucose sensor based on a dual-functional noble metal-nickel metal aerogel in a sweat dual-modal glucose sensing and detection device.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a dual-functional noble metal-nickel aerogel, a wearable sweat-based dual-modal enzyme-free glucose sensor, its preparation method, and its applications. The noble metal-nickel aerogel provided by this invention has a self-supporting dual structure of cross-linked nanowires and nanosheets, possessing highly efficient material and electron transport channels and a large number of catalytically active sites. The noble metal-nickel aerogel exhibits excellent catalytic performance for glucose, and can replace biological enzymes while maintaining high sensitivity and good stability. This invention utilizes microfluidic technology to collect sweat, which can improve sweat collection efficiency, requiring only a small amount of sweat for detection, and preventing sweat contamination and evaporation. Collection and detection can be completed under normal physiological perspiration conditions. The dual-modal detection method of electrochemical and colorimetric methods can be mutually verified, which can improve accuracy and reliability, and also meet the user's dual requirements for speed and precision. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the synthesis of precious metal-nickel aerogels provided in this application; Figure 2 Scanning electron microscope and transmission electron microscope images of the PtNi aerogel provided in Example 1; Figure 3 Scanning electron microscope and transmission electron microscope images of the AuNiFe aerogel provided in Example 2; Figure 4 The graph shows the results of the I test, response calibration curve, selectivity and long-term stability of the PtNi aerogel in Example 3. Figure 5 The graph shows the UV-Vis absorption spectrum, response calibration curve, selectivity, and long-term stability results of the AuNiFe aerogel in Example 4. Figure 6 This is a microfluidic channel diagram of the wearable sweat dual-modal enzyme-free glucose sensor based on precious metal-nickel aerogel, as described in this application. Figure 7 This is a schematic diagram showing the installation sequence of the wearable sweat-induced dual-modal enzyme-free glucose sensor based on the precious metal-nickel aerogel of this application. Figure 8 This is a physical image of the wearable sweat-based dual-modal enzyme-free glucose sensor based on precious metal-nickel aerogel, as described in this application. Figure 9 The calibration curves and sensing results of the electrochemical and colorimetric detection chip in sweat are shown in Example 6. Detailed Implementation

[0018] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0019] The main objective of this invention is to utilize the high catalytic performance and stability of the inorganic noble metal-nickel aerogel, and integrate it with a microfluidic device to accurately detect the glucose content in sweat through a dual-modal detection method combining electrochemical and colorimetric methods. This dual-functional noble metal-nickel aerogel can replace biological enzymes as the sensing material, providing high sensitivity while ensuring the stability of the sensor during long-term use, thereby effectively improving the accuracy and reliability of the detection.

[0020] To achieve the above objectives, the first aspect of the present invention provides a noble metal-nickel metal aerogel, including PtNi aerogel or AuNiFe aerogel. The PtNi aerogel is prepared by reacting a mixed solution of H2PtCl6 and NiCl2 with a NaBH4 solution, followed by freeze-drying. The AuNiFe aerogel is prepared by reacting a mixed solution of HAuCl4, NiCl2, and FeCl3 with a NaBH4 solution, followed by freeze-drying. The reaction time is 6-24 h.

[0021] The molar ratio of the mixed solution of H2PtCl6 and NiCl2 to the NaBH4 solution is 1:1~40. The mass fraction of H2PtCl6 in the mixed solution of H2PtCl6 and NiCl2 is 10 wt%. The molar ratio of H2PtCl6 to NiCl2 in the mixed solution of H2PtCl6 and NiCl2 is 1:0.1~6.

[0022] The molar ratio of the mixed solution of HAuCl4, NiCl2 and FeCl3 to the NaBH4 solution is 1:1~40; The mass fraction of HAuCl4 in the mixed solution of HAuCl4, NiCl2, and FeCl3 is 10 wt%. The molar ratio of HAuCl4, NiCl2, and FeCl3 in the mixed solution is 1:0.1~6:0.01~2.

[0023] The PtNi aerogel is used as an enzyme-free sensitive material; the AuNiFe aerogel is used as a colorimetric enzyme-sensitive material.

[0024] For example, the preparation of enzyme-free sensitive materials involves mixing H2PtCl6 with NiCl2 solution and NaBH4 to obtain PtNi hydrogel, and then freeze-drying it to obtain enzyme-free sensitive material PtNi aerogel. The preparation of colorimetric enzyme-sensitive materials involves mixing HAuCl4, NiCl2, and FeCl3 solutions with NaBH4 to obtain AuNiFe hydrogel, which is then freeze-dried to obtain AuNiFe aerogel, an enzyme-sensitive material.

[0025] See Figure 1 As shown, the metal precursor is reduced to atoms by NaBH4, and the metal atoms aggregate to grow into a cross-linked nanowire network. Meanwhile, some Ni in the alkaline solution after reduction continues to grow into nanosheets, ultimately forming a dual gel structure of cross-linked metal nanowires and nanosheets.

[0026] A second aspect of the present invention provides the application of a noble metal-nickel metal aerogel in a wearable sweat-based dual-modal enzyme-free glucose sensor.

[0027] A third aspect of this invention provides a wearable, sweat-modal, enzyme-free glucose sensor based on a dual-functional noble metal-nickel aerogel, see [link to relevant documentation]. Figure 7 As shown, it includes a PDMS flow channel layer 100 stacked together and a capping layer 200 covering the PDMS flow channel layer 100. The PDMS flow channel layer 100 is provided with multiple liquid inlets 101, as well as a first liquid storage chamber 102 and a second liquid storage chamber 103; the first liquid storage chamber 102 and the second liquid storage chamber 103 are connected by a first channel; each liquid inlet 101 is connected to the first liquid storage chamber 102 by a second channel; the second liquid storage chamber 103 is also provided with a liquid outlet 104; the capping layer 200 is provided with through holes 201 corresponding to each liquid inlet 101; An electrochemical detection chip 110 is disposed in the first liquid storage chamber 102; a colorimetric detection chip 120 is disposed in the second liquid storage chamber 103; the electrochemical detection chip 110 is made of PtNi aerogel; and the colorimetric detection chip 103 is made of AuNiFe aerogel.

[0028] For example, a wearable sweat-modal enzyme-free glucose sensor based on a dual-functional noble metal-nickel metal aerogel includes a microfluidic chip, as well as an electrochemical detection chip and a colorimetric detection chip modified with noble metal-nickel dual aerogel. The microfluidic chip includes a PDMS flow channel and a capping layer. Both the noble metal-nickel aerogel-modified electrochemical detection chip and the colorimetric detection chip are located in the PDMS flow channel layer, and the capping layer is located on top of the PDMS flow channel layer. The electrochemical detection chip is obtained by modifying a screen-printed electrode with a noble metal-nickel aerogel, and the colorimetric detection chip is obtained by modifying a filter paper with a noble metal-nickel aerogel, a colorimetric enzyme-sensitive material. The two chips realize the function of detecting glucose in sweat through electrochemical and colorimetric methods, respectively.

[0029] The electrochemical detection chip is prepared according to the following steps: a dispersion containing PtNi aerogel, Nafion perfluorinated resin and ultrapure water is prepared; the dispersion is drop-coated onto the surface of the working electrode of the screen-printed electrode and placed under an infrared baking lamp to dry; after drying, the electrochemical detection chip is obtained.

[0030] The colorimetric detection chip is prepared according to the following steps: preparing a dispersion containing AuNiFe aerogel and a dispersion containing 3,3',5,5'-tetramethylbenzidine (TMB); A dispersion containing AuNiFe aerogel was applied to the surface of a filter paper and dried under an infrared baking lamp. After drying, a dispersion containing 3,3',5,5'-tetramethylbenzidine was added, and after drying, a colorimetric detection chip was obtained.

[0031] PtNi and AuNi sensitive materials are used to prepare electrochemical detection chips and colorimetric detection chips, respectively. The detection chips are used in combination with electrochemical and colorimetric methods to detect the glucose content in sweat.

[0032] The capping layer is made of PDMS film or PET film material; the thickness of the capping layer is 300 μm. A fourth aspect of the present invention provides a method for preparing a wearable sweat-based dual-modal enzyme-free glucose sensor based on a bifunctional noble metal-nickel aerogel as described in any one of claims 6 to 8, characterized in that it comprises: Design the structure of the PDMS flow channel layer and fabricate the mold using photolithography; A PDMS flow channel layer with channels and a liquid storage cavity was prepared by molding, and multiple liquid inlets were processed at specific locations of the PDMS flow channel layer using a punch to obtain the PDMS flow channel layer. The top surface of the PDMS flow channel layer and the bottom surface of the capping layer are treated with oxygen plasma in a plasma processor. Then, the PDMS flow channel layer, electrochemical detection chip, colorimetric detection chip, and capping layer are immediately bonded and packaged to obtain a wearable sweat dual-modal enzyme-free glucose sensor based on a dual-functional noble metal-nickel metal aerogel.

[0033] The process involves loading the detection chip into the reservoir corresponding to the PDMS flow channel layer, covering the PDMS flow channel layer with a capping layer, and then encapsulating the chip.

[0034] The fifth aspect of the present invention provides the application of the wearable sweat dual-modal enzyme-free glucose sensor based on bifunctional noble metal-nickel metal aerogel as described in any one of claims 6 to 8 in a sweat dual-modal glucose sensing and detection device.

[0035] During the process, see Figure 7 As shown, a wearable sweat dual-modal enzyme-free glucose sensor based on precious metal-nickel aerogel is attached to the skin 300 on different parts of the human body. When sweating occurs through exercise or other means, the sweat flows into the first and second liquid storage chambers through the liquid inlet in the PDMS flow channel layer. After the sweat flows into the chamber containing the electrochemical detection chip, an electrochemical reaction occurs, and the concentration of glucose in the sweat is calculated using the generated current. After the sweat flows into the chamber containing the colorimetric detection chip, a colorimetric reaction occurs, a color image of the colorimetric chip is captured, and the RGB values ​​of the image are obtained using image processing software to calculate the glucose concentration in the sweat.

[0036] It should be noted that, unless otherwise specified, the experimental methods used in this invention are all conventional methods; and the reagents and materials used, unless otherwise specified, are all commercially available.

[0037] Example 1: Preparation of PtNi Aerogel Step S1: H2PtCl6 is mixed with NiCl2 solution and NaBH4 to obtain PtNi hydrogel; wherein the molar ratio of H2PtCl6 to NiCl2 is 1:4, the molar ratio of H2PtCl6 solution to NaBH4 is 1:20, the mass fraction of H2PtCl6 solution is 10wt%, and the reaction time of H2PtCl6 solution with NiCl2 solution and NaBH4 is 12h.

[0038] Specifically, H2PtCl6 solution, NiCl2 solution, and NaBH4 were mixed and stirred using a magnetic stirrer at 1500 rpm for 160 s. After stirring, a black solution was obtained. This black solution was stored in the dark for 12 h, and the black solid that appeared in the solution was the PtNi hydrogel. A schematic diagram of the synthesis is shown below. Figure 1 As shown.

[0039] Step S2: Freeze-dry the PtNi hydrogel to obtain PtNi aerogel; Specifically, the PtNi hydrogel needs to be washed with ultrapure water nine times before freeze-drying to remove residual impurities. The resulting black powder sample obtained through freeze-drying is the PtNi aerogel. The morphology of the PtNi aerogel is as follows... Figure 2 As shown. (Through) Figure 2Scanning electron microscopy (SEM) observation of PtNi aerogel in the middle A revealed a three-dimensional porous network structure. Figure 2 Transmission electron microscopy (TEM) analysis of the PtNi aerogel further revealed that it has a dual structure of cross-linked nanowires and nanosheets.

[0040] Example 2: Preparation of AuNiFe Aerogel Step S1: Mix HAuCl4, NiCl2, and FeCl3 solutions with NaBH4 to obtain AuNiFe hydrogel; wherein the molar ratio of HAuCl4, NiCl2, and FeCl3 is 1:4:1.5, the molar ratio of HAuCl4 solution to NaBH4 is 1:20, the mass fraction of HAuCl4 solution is 10 wt%, and the reaction time of HAuCl4 solution, NiCl2 solution, FeCl3 solution, and NaBH4 is 12 h.

[0041] Specifically, HAuCl4 solution, NiCl2 solution, FeCl3 solution, and NaBH4 were mixed and stirred using a magnetic stirrer at 1500 rpm for 160 s. After stirring, a black solution was obtained. This black solution was stored in the dark for 12 h, and the black solid that appeared in the solution was the AuNiFe hydrogel. A schematic diagram of the synthesis is shown below. Figure 1 As shown.

[0042] Step S2: Freeze-dry the AuNiFe hydrogel to obtain AuNiFe aerogel; Specifically, the AuNiFe hydrogel needs to be washed with ultrapure water nine times before freeze-drying to remove residual impurities. The resulting black powder sample obtained through freeze-drying is the AuNiFe aerogel. The morphology of the AuNiFe aerogel is as follows: Figure 3 As shown, Figure 3 A represents SEM and Figure 3 In the image, B represents TEM, which shows that the PtNi aerogel exhibits a dual structure of a three-dimensional porous network and cross-linked nanowires and nanosheets.

[0043] Example 3: Fabrication and Testing of Electrochemical Detection Chip An electrochemical detection chip was prepared using the PtNi aerogel provided in Example 1: Step S1: Prepare a dispersion containing PtNi aerogel, Nafion perfluorinated resin and ultrapure water of a certain volume.

[0044] Specifically, 2 mg of PtNi aerogel was dispersed in 1 mL of ultrapure water to obtain a 2 mg / mL PtNi aerogel aqueous solution; Nafion perfluorinated resin was added to the PtNi aerogel aqueous solution, and the mixture was ultrasonically vibrated for about 2 min until it was uniformly dispersed to obtain a PtNi aerogel dispersion with a concentration of 2 mg / mL, wherein the Nafion perfluorinated resin accounted for 0.5% of the total volume of the PtNi aerogel dispersion. In step S2, a certain volume of a dispersion containing PtNi aerogel, Nafion perfluorinated resin and water is drop-coated onto the surface of the screen-printed electrode working electrode using a drop-coating method. The electrode is then placed under an infrared baking lamp to dry, and an electrochemical detection chip is obtained after drying.

[0045] Specifically, the volume of the PtNi aerogel dispersion was 10 μL, and the drying time was 30 min. The screen-printed electrode used was a pre-treated screen-printed electrode that was purchased. This electrode included three regions: a working electrode, a reference electrode, and a counter electrode. The substrate was PET material.

[0046] Electrochemical sensing performance testing: Step S1 involves performing the following three experiments on the prepared electrochemical detection chip to verify the sensitivity, anti-interference, and long-term stability of the electrochemical sensor for glucose detection. (See [link to relevant documentation]). Figure 4 As shown.

[0047] Step S2, the first step of the experiment is to detect the electrochemical response performance of glucose. 0.1 M PBS (pH=7) solution is used as electrolyte, and glucose solutions of different concentrations are added sequentially. A linear relationship is constructed based on the current response value. Figure 4 The results in A and B show that there is a good linear relationship between current and concentration, and the electrochemical detection range of the material is 0~3.0 mM, with a detection limit of 18.5 μM.

[0048] Step S3, the second experiment, is to test the anti-interference ability of the glucose electrochemical sensing detection. The specific process is as follows: During the detection, the corresponding interfering substances (1 mM urea, 0.2 mM uric acid, 0.2 mM ascorbic acid, 10 mM lactic acid, and 10 mM KCl) are added to the electrochemical sensing layer respectively, and the changes in the electrochemical signal are observed. Figure 4 The results from C indicate that the interference has an effect of less than 5% on the current signal, indicating that the material has good anti-interference performance.

[0049] Step S4, the third experiment, is to test the long-term stability of the glucose electrochemical sensing detection. The specific process is as follows: the electrochemical detection chip is stored at 4 ℃ for 1, 3, 5, 10, 15 and 20 days respectively. Cyclic voltammetry tests are performed on the electrochemical detection chip in 5 mM glucose PBS solution (0.1 M pH=7) to observe the changes in current. Figure 4 The results from D indicate that the RSD of the electrochemical response current signal is less than 5%, suggesting that the PtNi aerogel has good long-term stability.

[0050] Example 4: Fabrication and Testing of Colorimetric Detection Chip A colorimetric detection chip was prepared using the AuNiFe aerogel provided in Example 2: Step S1: Prepare a certain volume of AuNiFe aerogel dispersion and a dispersion containing TMB.

[0051] Specifically, 2 mg of AuNiFe aerogel was dispersed in 1 mL of ultrapure water to obtain an aqueous solution of AuNiFe aerogel with a concentration of 2 mg / mL. The mixture was ultrasonically agitated for about 20 min until it was uniformly dispersed to obtain an AuNiFe aerogel dispersion with a concentration of 2 mg / mL. 0.1 mmol TMB was dispersed in 10 mL of water and the mixture was ultrasonically agitated for about 10 min until it was uniformly dispersed to obtain a dispersion with a concentration of 10 mmol / L.

[0052] In step S2, a certain volume of dispersion containing AuNiFe aerogel is applied to the surface of a filter paper using a drop-coating method. The paper is then dried under an infrared baking lamp. After drying, a TMB dispersion solution is added to the paper, and the resulting colorimetric detection chip is obtained after further drying.

[0053] Specifically, the volume of AuNiFe aerogel dispersion was 100 μL, and the drying time was 25 min. The volume of TMB dispersion was 100 μL, and the drying time was 4 h.

[0054] Colorimetric sensor performance test: Step S1: Prepare a dispersion of AuNiFe aerogel and TMB in a certain volume. The concentration of the AuNiFe aerogel dispersion is 1 mg / mL. -1 The concentration of the 100 μL TMB dispersion was 10 mM.

[0055] Step S2 involves performing the experiments described in steps one through three on the prepared dispersion to verify the colorimetric sensor's sensitive response to glucose, its resistance to interference, and its long-term stability. (See step S2 for details.) Figure 5 As shown.

[0056] Step S3, the first step of the experiment is to detect the colorimetric response performance of glucose. The specific process is as follows: 50 μL of LuNiFe aerogel dispersion and 100 μL of glucose solutions of different concentrations were added to 350 μL of HAc-NaAc (pH=7). After reacting for 10 min, 100 μL of 10 mM 3,3',5,5'-tetramethylbiphenyl (TMB) solution was added and reacted for 3 min. The UV-Vis spectrum was measured, and the absorbance value at 652 nm was recorded to establish a linear relationship between the concentration of each substance and the absorbance value. Figure 5 As shown in Figures A and B, the AuNiFe aerogel exhibits a good linear response to glucose, with a detection limit of 20.0 μM and a detection range of 0–6.0 mM.

[0057] Step S4, the second step of the experiment, is to test the anti-interference ability of the glucose colorimetric sensor. The specific process is as follows: During the detection, the corresponding interfering substances (1 mM urea, 0.2 mM uric acid, 0.2 mM ascorbic acid, 10 mM lactic acid, and 10 mM KCl) are added to the solution respectively, and the changes in the absorbance value at 652 nm are observed and recorded. Figure 5 As shown in Figure C, the results indicate that the absorbance change is less than 5%, suggesting that AuNiFe aerogel has good anti-interference properties.

[0058] Step S5, the third experiment, is to test the long-term stability of the glucose colorimetric sensor. The specific process is as follows: AuNiFe aerogel is stored at 4 ℃ for 1, 3, 5, 10, 15 and 20 days respectively, and the absorbance value at 652 nm is recorded during the detection. Figure 5 As shown in Figure D, the results show that the absorbance value decreased to 85%, indicating that the AuNiFe aerogel has good long-term stability.

[0059] Example 5: Design and fabrication process of PDMS flow channel layer (microfluidic chip) Step S1: First, the structure of the PDMS flow channel layer is designed using SolidWorks software, and the mold is fabricated using photolithography. Detailed drawings are shown below. Figure 6 As shown, the microfluidic structure consists of three inlets with a diameter of 2 mm, a first reservoir with a diameter of 8 mm, a second reservoir with a diameter of 6 mm, an outlet with a width of 0.4 mm, and a channel with a width of 0.4 mm. The depth of all regions is 0.2 mm.

[0060] Step S2: A PDMS flow channel layer with channels and a reservoir cavity is prepared using a molding method. The preparation process is as follows: The PDMS preparation agent and curing agent are mixed in a 10:1 ratio and stirred in a beaker for 30 min. Then, the mixture is placed in a vacuum environment at room temperature to remove excess air bubbles and form a PDMS prepolymer. The prepolymer is uniformly poured into the processed mold and cured at 70 °C for 2 h. Finally, the PDMS flow channel layer is demolded.

[0061] Example 6: Preparation and application of a wearable sweat-based dual-modal enzyme-free glucose sensor: Step S1: The electrochemical detection chip provided in Example 3 and the colorimetric detection chip provided in Example 4 are encapsulated into the liquid storage chamber in the PDMS flow channel layer provided in Example 5. The specific process is as follows: Three 2 mm diameter inlets were machined at specific locations in the PDMS flow channel layer using a punch. Then, the top surface of the PDMS flow channel layer and the bottom surface of the capping layer were subjected to oxygen plasma treatment in a plasma processor for 3 minutes. After removal, they were immediately bonded and packaged in the following order: PDMS flow channel, electrochemical detection chip, colorimetric detection chip, and capping layer. Detailed figures are shown below. Figure 7 As shown in the diagram. The electrochemical detection chip corresponds to the first liquid storage chamber with a diameter of 8 mm, and the colorimetric detection chip corresponds to the second liquid storage chamber with a diameter of 6 mm. The actual device diagram is shown below. Figure 8 As shown.

[0062] Step S2 involves testing the electrochemical detection chip's glucose sensing response in sweat. The specific process is as follows: A concentration gradient is constructed within the selected glucose detection range. Testing is then conducted in artificial sweat to establish a linear relationship between the concentration of each substance and the current signal. Based on this linear relationship, the corresponding detection limit is derived. For example... Figure 9 As shown in Figure A, the lower limit of electrochemical detection is 14.7 μM, and the detection range is 0~2.0 mM, which meets the actual needs of sweat detection.

[0063] Step S3 involves testing the colorimetric detection chip's glucose sensing response in sweat. The specific process is as follows: A concentration gradient is constructed within a selected glucose detection range. Testing is conducted in artificial sweat. Photos of the colorimetric detection chip at different concentrations are taken using a smartphone. The RGB values ​​of the colorimetric detection chip are then analyzed using color picker software. A linear regression curve is established with R / (R+G+B) as the ordinate and glucose concentration as the abscissa to achieve visual glucose detection. The corresponding detection limit is then derived based on the linear relationship. Figure 9 As shown in Figure B, the lower limit of colorimetric detection is 30 μM, and the detection range is 0~3.0 mM, which meets the actual needs of sweat detection.

[0064] Step S4: In order to verify the practicality of electrochemical-colorimetric dual-modal analysis, sweat with different glucose concentrations was subjected to sensor detection and analysis. Figure 9 As shown in Figure C, the electrochemical and colorimetric analysis results are consistent with the standard concentration (see Appendix). Figure 9 This indicates that the wearable sweat enzyme-free electrochemical-colorimetric dual-modal detection system has significant application value in monitoring sweat glucose.

[0065] Example 7: Preparation of PtNi Aerogel Step S1: H2PtCl6 is mixed with NiCl2 solution and NaBH4 to obtain PtNi hydrogel; wherein, the molar ratio of H2PtCl6 to NiCl2 is 1:0.1, the molar ratio of H2PtCl6 solution to NaBH4 is 1:1, the mass fraction of H2PtCl6 solution is 10wt%, and the reaction time of H2PtCl6 solution with NiCl2 solution and NaBH4 is 6 h.

[0066] Specifically, H2PtCl6 solution was mixed with NiCl2 solution and NaBH4 and stirred with a magnetic stirrer at a speed of 500 rpm for 30 seconds. After stirring, a black solution was obtained. The black solution was stored in the dark for 12 hours. The black solid that appeared in the solution was PtNi hydrogel.

[0067] Step S2: Freeze-dry the PtNi hydrogel to obtain PtNi aerogel; Specifically, the PtNi hydrogel needs to be washed with ultrapure water eight times before freeze-drying to remove residual impurities. The black powder sample obtained by freeze-drying is the PtNi aerogel.

[0068] Example 8: Preparation of PtNi aerogel Step S1: H2PtCl6 is mixed with NiCl2 solution and NaBH4 to obtain PtNi hydrogel; wherein the molar ratio of H2PtCl6 to NiCl2 is 1:6, the molar ratio of H2PtCl6 solution to NaBH4 is 1:40, the mass fraction of H2PtCl6 solution is 10wt%, and the reaction time of H2PtCl6 solution with NiCl2 solution and NaBH4 is 24 h.

[0069] Specifically, H2PtCl6 solution was mixed with NiCl2 solution and NaBH4 and stirred with a magnetic stirrer at a speed of 3000 rpm for 240 s. After stirring, a black solution was obtained. After storing the black solution in the dark for 12 hours, the black solid that appeared in the solution was PtNi hydrogel.

[0070] Step S2: Freeze-dry the PtNi hydrogel to obtain PtNi aerogel; Specifically, the PtNi hydrogel needs to be washed with ultrapure water 10 times before freeze-drying to remove residual impurities. The black powder sample obtained by freeze-drying is the PtNi aerogel.

[0071] Example 9: Preparation of AuNiFe Aerogel Step S1: Mix HAuCl4, NiCl2, and FeCl3 solutions with NaBH4 to obtain AuNiFe hydrogel; wherein the molar ratio of HAuCl4, NiCl2, and FeCl3 is 1:0.1:0.01, the molar ratio of HAuCl4 solution to NaBH4 is 1:1, the mass fraction of HAuCl4 solution is 10 wt%, and the reaction time of HAuCl4 solution, NiCl2 solution, FeCl3 solution, and NaBH4 is 6 h.

[0072] Specifically, HAuCl4 solution, NiCl2 solution, FeCl3 solution and NaBH4 were mixed and stirred with a magnetic stirrer at a speed of 500 rpm for 30 seconds. After stirring, a black solution was obtained. After storing the black solution in the dark for 12 hours, the black solid that appeared in the solution was AuNiFe hydrogel.

[0073] Step S2: Freeze-dry the AuNiFe hydrogel to obtain AuNiFe aerogel; Specifically, before freeze-drying, the AuNiFe hydrogel needs to be washed with ultrapure water 8-10 times to remove residual impurities. The black powder sample obtained by freeze-drying is the AuNiFe aerogel.

[0074] Example 10: Preparation of AuNiFe Aerogel Step S1: Mix HAuCl4, NiCl2, and FeCl3 solutions with NaBH4 to obtain AuNiFe hydrogel; wherein the molar ratio of HAuCl4, NiCl2, and FeCl3 is 1:6:2, the molar ratio of HAuCl4 solution to NaBH4 is 1:40, the mass fraction of HAuCl4 solution is 10 wt%, and the reaction time of HAuCl4 solution, NiCl2 solution, FeCl3 solution, and NaBH4 is 24 h.

[0075] Specifically, HAuCl4 solution, NiCl2 solution, FeCl3 solution and NaBH4 were mixed and stirred with a magnetic stirrer at a speed of 3000 rpm for 240 s. After stirring, a black solution was obtained. After storing the black solution in the dark for 12 h, the black solid that appeared in the solution was AuNiFe hydrogel.

[0076] Step S2: Freeze-dry the AuNiFe hydrogel to obtain AuNiFe aerogel; Specifically, the AuNiFe hydrogel needs to be washed with ultrapure water 10 times before freeze-drying to remove residual impurities. The black powder sample obtained by freeze-drying is the AuNiFe aerogel.

[0077] Example 11 An electrochemical detection chip was prepared using the PtNi aerogel provided in Example 8: Step S1: Prepare a dispersion containing PtNi aerogel, Nafion perfluorinated resin and ultrapure water of a certain volume.

[0078] Specifically, 2 mg of PtNi aerogel was dispersed in 1 mL of ultrapure water to obtain a 2 mg / mL PtNi aerogel aqueous solution; Nafion perfluorinated resin was added to the PtNi aerogel aqueous solution, and the mixture was ultrasonically vibrated for about 2 min until it was uniformly dispersed to obtain a PtNi aerogel dispersion with a concentration of 2 mg / mL, wherein the Nafion perfluorinated resin accounted for 0.5% of the total volume of the PtNi aerogel dispersion. In step S2, a certain volume of a dispersion containing PtNi aerogel, Nafion perfluorinated resin and water is drop-coated onto the surface of the screen-printed electrode working electrode using a drop-coating method. The electrode is then placed under an infrared baking lamp to dry, and an electrochemical detection chip is obtained after drying.

[0079] Specifically, the volume of the PtNi aerogel dispersion is 1~20 μL, and the drying time is 5~60 min; the screen-printed electrode used is a purchased pre-treated screen-printed electrode, which includes three regions: working electrode, reference electrode and counter electrode, and the substrate is PDMS material.

[0080] Example 12 A colorimetric detection chip was prepared using the AuNiFe aerogel provided in Example 10: Step S1: Prepare a certain volume of dispersion containing AuNiFe aerogel and TMB.

[0081] Specifically, 2 mg of AuNiFe aerogel was dispersed in 1 mL of ultrapure water to obtain an aqueous solution of AuNiFe aerogel with a concentration of 2 mg / mL. The mixture was ultrasonically agitated for about 20 min until it was uniformly dispersed to obtain an AuNiFe aerogel dispersion with a concentration of 2 mg / mL. 0.1 mmol TMB was dispersed in 10 mL of water and the mixture was ultrasonically agitated for about 10 min until it was uniformly dispersed to obtain a dispersion with a concentration of 10 mmol / L.

[0082] In step S2, a certain volume of dispersion containing AuNiFe aerogel is applied to the surface of a filter paper using a drop-coating method. The paper is then dried under an infrared baking lamp. After drying, a TMB dispersion solution is added to the paper, and the resulting colorimetric detection chip is obtained after further drying.

[0083] Specifically, the volume of AuNiFe aerogel dispersion is 1–200 μL, and the drying time is 10–40 min. The volume of TMB dispersion is 100 μL, and the drying time is 2–6 h.

[0084] In summary, this invention provides a dual-functional noble metal-nickel aerogel, a wearable sweat dual-modal enzyme-free glucose sensor, its preparation method, and its applications. First, a highly sensitive and selective noble metal-nickel-based dual-structure aerogel is prepared to replace biological enzymes as the sensing material. Then, an electrochemical and colorimetric detection chip is fabricated, and the detection chip is assembled with a microfluidic device to form a wearable device. This enables dual-modal enzyme-free detection of glucose in sweat using both electrochemical and colorimetric methods. The preparation method includes the preparation and modification of the sensitive material, the design and fabrication of the microfluidic system, and the assembly of the sensor. Innovative material design and process optimization enable the sensor to accurately monitor the concentration of glucose in sweat and exhibit excellent long-term stability and anti-interference capabilities in practical applications. This technology provides an effective and reliable solution for precise human health monitoring.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A noble metal-nickel metal aerogel, characterized in that, Including PtNi aerogel or AuNiFe aerogel; The PtNi aerogel is prepared by reacting a mixed solution of H2PtCl6 and NiCl2 with a NaBH4 solution and then freeze-drying it; the AuNiFe aerogel is prepared by reacting a mixed solution of HAuCl4, NiCl2 and FeCl3 with a NaBH4 solution and then freeze-drying it.

2. The noble metal-nickel metal aerogel according to claim 1, characterized in that, The molar ratio of the mixed solution of H2PtCl6 and NiCl2 to the NaBH4 solution is 1:1~40; The mass fraction of H2PtCl6 in the mixed solution of H2PtCl6 and NiCl2 is 10 wt%. The molar ratio of H2PtCl6 to NiCl2 in the mixed solution of H2PtCl6 and NiCl2 is 1:0.1~6.

3. The noble metal-nickel metal aerogel according to claim 1, characterized in that, The molar ratio of the mixed solution of HAuCl4, NiCl2 and FeCl3 to the NaBH4 solution is 1:1~40; The mass fraction of HAuCl4 in the mixed solution of HAuCl4, NiCl2, and FeCl3 is 10 wt%. The molar ratio of HAuCl4, NiCl2, and FeCl3 in the mixed solution is 1:0.1~6:0.01~2.

4. The noble metal-nickel metal aerogel according to claim 1, characterized in that, The reaction time is 6-24 hours.

5. The application of the noble metal-nickel metal aerogel according to any one of claims 1 to 4 in a wearable sweat dual-modal enzyme-free glucose sensor.

6. A wearable sweat-based dual-modal enzyme-free glucose sensor based on a bifunctional noble metal-nickel aerogel, characterized in that, It includes a PDMS flow channel layer stacked together and a capping layer covering the PDMS flow channel layer; The PDMS flow channel layer is provided with multiple liquid inlets, as well as a first liquid storage chamber and a second liquid storage chamber; the first liquid storage chamber and the second liquid storage chamber are connected by a first channel; each liquid inlet is connected to the first liquid storage chamber by a second channel; the second liquid storage chamber is also provided with an outlet; the capping layer is provided with through holes corresponding to each liquid inlet; An electrochemical detection chip is disposed in the first liquid storage chamber; a colorimetric detection chip is disposed in the second liquid storage chamber; the electrochemical detection chip is made of PtNi aerogel; and the colorimetric detection chip is made of AuNiFe aerogel.

7. The wearable sweat-based dual-modal enzyme-free glucose sensor based on a bifunctional noble metal-nickel aerogel according to claim 6, characterized in that, The electrochemical detection chip is prepared according to the following steps: a dispersion containing PtNi aerogel, Nafion perfluorinated resin and ultrapure water is prepared; the dispersion is drop-coated onto the surface of the working electrode of the screen-printed electrode and placed under an infrared baking lamp to dry; after drying, the electrochemical detection chip is obtained.

8. The wearable sweat-based dual-modal enzyme-free glucose sensor based on a bifunctional noble metal-nickel aerogel according to claim 6, characterized in that, The colorimetric detection chip is prepared according to the following steps: preparing a dispersion containing AuNiFe aerogel and a dispersion containing 3,3',5,5'-tetramethylbenzidine; A dispersion containing AuNiFe aerogel was applied to the surface of a filter paper and dried under an infrared baking lamp. After drying, a dispersion containing 3,3',5,5'-tetramethylbenzidine was added, and after drying, a colorimetric detection chip was obtained.

9. A method for preparing a wearable sweat-based dual-modal enzyme-free glucose sensor based on a bifunctional noble metal-nickel aerogel as described in any one of claims 6 to 8, characterized in that, include: Design the structure of the PDMS flow channel layer and fabricate the mold using photolithography; A PDMS flow channel layer with channels and a liquid storage cavity was prepared by molding, and multiple liquid inlets were processed at specific locations of the PDMS flow channel layer using a punch to obtain the PDMS flow channel layer. The top surface of the PDMS flow channel layer and the bottom surface of the capping layer are treated with oxygen plasma in a plasma processor. Then, the PDMS flow channel layer, electrochemical detection chip, colorimetric detection chip, and capping layer are immediately bonded and packaged to obtain a wearable sweat dual-modal enzyme-free glucose sensor based on a dual-functional noble metal-nickel metal aerogel.

10. The application of the wearable sweat bimodal enzyme-free glucose sensor based on bifunctional noble metal-nickel metal aerogel as described in any one of claims 6 to 8 in a sweat bimodal glucose sensing and detection device.

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