A wearable colorimetric sweat sensor patch based on a paper chip

Abstract

This invention discloses a wearable colorimetric sweat sensing patch based on a paper chip, belonging to the field of physiological state detection. The sensor patch structure includes an adhesive layer with an inlet, a paper chip layer, and a color reference label. By employing ink direct writing technology and using polydimethylsiloxane as a hydrophobic barrier, independent detection areas are constructed on the substrate, effectively preventing crosstalk between detection units. Simultaneously, a Prussian blue analog nanozyme is synthesized for stable and visualized colorimetric detection of glucose in sweat; another detection area is used for pH value detection. The sensor patch prepared by this invention combines breathability, flexibility, and good portability. The color reference label enables intuitive and visualized reading of detection results, making it suitable for fields such as sports and health monitoring.

Description

Technical Field

[0001] This invention belongs to the field of physiological state detection, specifically relating to a wearable colorimetric sweat sensor patch based on a paper chip. Background Technology

[0002] Sweat is rich in various biomarkers such as glucose, levodopa, ascorbic acid, estradiol, and uric acid. Its simple and non-invasive collection method makes it an ideal sample source for portable health monitoring and diagnosis of diseases such as Parkinson's disease, cystic fibrosis, diabetes, and cardiovascular diseases. Currently, wearable sensors that can be directly attached to the skin to monitor sweat composition in real time and provide data feedback to the user are widely used. These sensors encompass various detection technologies, including electrochemical methods, electrochemiluminescence methods, colorimetric methods, and fluorescence methods. Among these, colorimetric methods are widely used in rapid sweat analysis due to their simple structure, convenient preparation, and low cost. These sensors do not rely on additional signal reading equipment, and the detection results can be directly observed with the naked eye, making them particularly suitable for remote areas with relatively scarce medical resources.

[0003] However, colorimetric analysis of metabolites such as glucose or lactic acid in sweat currently relies primarily on natural enzymes. These enzymes suffer from inherent drawbacks, including high cost, limited production scale, and susceptibility to pH fluctuations, temperature changes, and organic solvents, severely restricting their practical application in long-term stable operation scenarios. Furthermore, when detecting multiple indicators simultaneously, signal crosstalk can easily occur between different reagent areas of paper-based colorimetric sensors, leading to decreased detection accuracy.

[0004] The purpose of this invention is to provide a wearable colorimetric sweat sensing patch based on a paper chip to solve the aforementioned problems. This invention synthesizes a Prussian blue analogue and uses it as a nanozyme to achieve stable and visual detection of glucose in sweat. Simultaneously, polydimethylsiloxane (PDMS) is selected as a hydrophobic barrier material to prepare a paper-based chip with sweat collection function. This design effectively avoids cross-interference between colorimetric signals by constructing independent analysis channels; its patch structure combines flexibility and simplicity, significantly improving the overall portability of the device, making it convenient for users to carry and perform tests at any time. Summary of the Invention

[0005] To address the problems of poor reagent stability and crosstalk between colorimetric signals in existing colorimetric sensors, this invention provides a wearable colorimetric sweat sensor patch based on a paper chip, suitable for applications such as motion detection and health monitoring. By using synthetic nanozymes instead of natural enzymes, the stability of long-term detection is improved.

[0006] This invention synthesizes a Prussian blue analogue and uses it as a nanozyme to achieve stable and visual detection of glucose in sweat. Simultaneously, PDMS is used as the hydrophobic barrier, serving as the substrate for the paper chip used to collect sweat, thus reducing crosstalk between sensing units.

[0007] The present invention solves the above-mentioned technical problems through the following technical means:

[0008] A first aspect of the present invention provides a wearable colorimetric sweat sensing patch based on a paper chip, comprising a paper chip layer, an adhesive layer, and a color reference label;

[0009] Furthermore, the paper chip layer includes the substrate and a hydrophobic barrier formed on the substrate.

[0010] Furthermore, the hydrophobic barrier divides the substrate surface into at least two physically isolated detection zones; wherein at least one of the detection zones is a glucose detection zone, which is loaded with a detection reagent containing a chromogenic substrate, nanozyme and glucose oxidase; at least one of the detection zones is loaded with a detection reagent for detecting pH.

[0011] The nanozyme is a Prussian blue analog nanozyme.

[0012] Prussian blue analog nanozymes are used as nanozymes to work synergistically with glucose oxidase to achieve stable and visual detection of glucose in sweat.

[0013] Furthermore, the preparation method of the Prussian blue analog nanozyme is as follows:

[0014] Sodium ferrocyanide was dissolved in sodium chloride solution, followed by the addition of polyvinylpyrrolidone to dissolve it. Hydrochloric acid was then added until the system became acidic. The mixture was stirred in a hot water bath and cooled to room temperature to obtain the product. The product was washed, and the precipitate was collected by centrifugation, dried, and ground to obtain the final product.

[0015] Furthermore, in the preparation method of the nanozyme, the hot water bath stirring conditions are 85-95 ℃, and the stirring time is 8-12 h.

[0016] Furthermore, the final concentration of sodium ferrocyanide in the reaction system is 1.5-1.7 mmol / L, and the final concentration of polyvinylpyrrolidone in the reaction system is 0.08-0.12 g / L.

[0017] Furthermore, the adhesive layer is a double-sided adhesive layer, namely medical double-sided tape.

[0018] Furthermore, the adhesion layer is provided with liquid inlet holes corresponding to the location of the detection area.

[0019] Furthermore, the color reference label is equipped with standard colorimetric cards corresponding to different detection indicators.

[0020] Furthermore, the hydrophobic barrier is formed by ink direct writing technology, followed by PDMS molding and curing.

[0021] This invention provides a method for preparing the above-mentioned wearable colorimetric sweat sensor patch based on a paper chip, comprising the following steps:

[0022] Preparation of Prussian blue analog nanozymes;

[0023] A hydrophobic barrier is constructed on the substrate, and after the detection area is formed, it is cured.

[0024] The corresponding detection reagents are fixed on the detection area respectively;

[0025] The paper chip layer, the adhesive layer, and the color reference label are aligned and bonded in sequence to assemble a complete sensor patch.

[0026] The curing conditions for the hydrophobic barrier are 70-90 ℃ and heating for 0.5-2 h.

[0027] When loading reagents into the glucose detection zone, a chromogenic substrate, a Prussian blue analog nanozyme, and glucose oxidase are added and fixed sequentially.

[0028] The Prussian blue analog nanozyme exerts its peroxidase-like activity to catalyze the oxidation of chromogenic substrates by peroxide, producing a visually observable color change. The color intensity is related to the glucose concentration of the sweat being tested. The pH detection zone, isolated by a hydrophobic barrier, directly reflects the acidity or alkalinity of sweat through the color change of the pH indicator. The two do not interfere with each other and work together to complete the in-situ, simultaneous analysis of key sweat indicators.

[0029] Furthermore, the chromogenic substrate is any one of 3,3',5,5'-tetramethylbenzidine or 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt.

[0030] Compared with the prior art, the advantages of the present invention are:

[0031] 1. This invention uses chemically prepared Prussian blue analog nanozymes to replace traditional natural peroxidases. Its catalytic activity is insensitive to environmental factors such as pH and temperature, and it has excellent chemical stability and long-term storage stability, thus solving the core bottleneck of easy inactivation of natural enzymes. In the glucose detection zone, glucose in sweat is converted into gluconic acid and hydrogen peroxide under the catalysis of glucose oxidase. Then, the Prussian blue analog nanozyme and glucose oxidase are functionally linked, and together they realize stable and visual colorimetric detection of glucose in sweat.

[0032] 2. This invention utilizes ink direct writing technology to construct a hydrophobic barrier on the substrate. After curing, PDMS forms a physical isolation structure with excellent flexibility and chemical stability. This completely separates the areas corresponding to different detection indicators, effectively preventing the lateral diffusion of sweat between detection areas and cross-contamination of detection reagents, thus ensuring the independence and accuracy of multi-indicator detection.

[0033] 3. The sensor patch prepared by this invention has a thin and flexible structure. It can be directly attached to the skin using a medical-grade adhesive layer. It is highly breathable and does not require an external power source or complex instruments, enabling the visual reading of sweat-related information. The sensor patch is simple to prepare, has low material costs, is easy to operate and mass-produce, and is conducive to large-scale promotion. This enables wearable and in-situ applications, greatly improving user experience and applicable scenarios. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the sweat sensing patch provided in Embodiment 1 of the present invention, showing the layered structure (left) and top view (right); 1-adhesive layer, 2-paper chip layer, 21-substrate, 22-hydrophobic barrier, 3-analytical reagent, 4-color reference label;

[0035] Figure 2 Typical absorption spectra of different reaction systems; the concentrations of Prussian blue analogues are PBA-1, PBA-2 and PBA-3, corresponding to 40 μg / mL, 60 μg / mL and 100 μg / mL, respectively;

[0036] Figure 3 The graphs show the catalytic performance at different pH and temperature conditions. Figure 3 (a) Relative activities of Prussian blue analog nanozymes under different pH conditions. Figure 3 (b) The relative activity of Prussian blue analog nanozymes under different temperature conditions;

[0037] Figure 4 A comparison of the long-term storage stability of Prussian blue analog nanozymes;

[0038] Figure 5 This is an analytical diagram showing the long-term stability of the sensing patch of the present invention against sweat.

[0039] Figure 6 This is a comparison chart of the detection results of the sensing patch of the present invention and the pH meter on the pH of sweat;

[0040] Figure 7 A comparison chart of the detection results of glucose in sweat by the invention of the sensor patch and the high performance liquid chromatography. Detailed Implementation

[0041] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0042] This invention relates to a method for preparing a wearable colorimetric sweat sensor patch, the structure of which is as follows: Figure 1 As shown, it includes the following steps:

[0043] S1. Preparation of Prussian blue analog nanozymes, specifically:

[0044] Sodium ferrocyanide and polyvinylpyrrolidone were dissolved sequentially in sodium chloride solution, and hydrochloric acid was added to adjust the pH to acidic. The reaction was pre-reacted at room temperature. The reaction system was then heated in a water bath at 85-95 ℃ with continuous stirring for 8-12 hours. The reaction product was obtained after cooling, centrifugation, washing with alternating water and alcohol, drying, and grinding.

[0045] S2. Preparation of a wearable colorimetric sweat sensing patch, specifically:

[0046] The filter paper was cut into circular thin slices with a diameter of 2.4 cm, and then PDMS was used as ink to print two circular detection areas with a diameter of 5 mm on the filter paper using ink direct writing technology.

[0047] In the above circular detection zone, glucose detection area and pH detection area are separated, and analytical reagents for glucose and pH detection are fixed on the corresponding detection areas;

[0048] In the glucose detection zone, 3,3',5,5'-tetramethylbenzidine, Prussian blue analog nanozyme, glucose oxidase, Prussian blue analog and 3,3',5,5'-tetramethylbenzidine are added sequentially.

[0049] In the pH detection area, add 2 μL of a universal indicator;

[0050] After the reagents in the glucose detection area and pH detection area are modified, the paper chip layer with the reagents fixed, the double-sided adhesive layer with the liquid inlet hole and the color reference label are aligned and attached in sequence to assemble a complete sensor patch.

[0051] The parameters and sources of some of the substances used in the embodiments and comparative examples of this invention are as follows:

[0052] Polyvinylpyrrolidone: CAS No.: 9003-39-8, Molecular weight: 40000;

[0053] PDMS precursor fluid and curing agent: DC184, both sourced from Shenzhen Songsen New Materials Co., Ltd.

[0054] The preparation method for fresh PDMS is as follows: Mix the PDMS precursor liquid and the curing agent at a mass ratio of 10:1, stir at 60-100 rpm for 1-2 min, and then let it stand at 4 ℃ for 30 min until the air bubbles are removed.

[0055] Universal indicator for pH testing: Product No.: U196531; Applicable range: 3-12; Source: Aladdin.

[0056] Example 1: Prussian blue nanozyme prepared by a single iron source acidic hydrothermal method

[0057] The wearable colorimetric sweat sensor patch based on a paper chip provided in this embodiment is prepared using the following specific steps:

[0058] S1. The preparation method of Prussian blue analog nanozyme is as follows:

[0059] Dissolve 1.7 mmol / L sodium ferrocyanide in 0.1 mol / L sodium chloride solution, add 5 mg of polyvinylpyrrolidone, and after dissolution, add hydrochloric acid to adjust the pH to 1.5-3.0. Stir at room temperature for 1 h.

[0060] The product was then placed in a 90 °C water bath and magnetically stirred for 12 h. After cooling to room temperature, the product was washed 6 times with water and ethanol alternately, and the blue precipitate was collected by centrifugation.

[0061] The obtained precipitate was dried in a vacuum oven and then ground to obtain the Prussian blue analog nanozyme.

[0062] S2. Preparation of a wearable colorimetric sweat sensing patch, specifically:

[0063] First, cut the filter paper into circular thin slices with a diameter of 2.4 cm; then, using freshly prepared PDMS as ink, print two circular detection areas with a diameter of 5 mm on the filter paper using ink direct writing technology.

[0064] The analytical reagents used for glucose and pH detection are fixed on the corresponding circular detection areas, namely the glucose detection area and the pH detection area.

[0065] In the glucose detection area, 3 μL of 0.01 mol / L 3,3',5,5'-tetramethylbenzidine, 3 μL of 0.2 mg / mL Prussian blue analogue, 3 μL of 2 mg / mL glucose oxidase, 3 μL of 0.2 mg / mL Prussian blue analogue, and 3 μL of 0.01 mol / L 3,3',5,5'-tetramethylbenzidine were added dropwise in sequence.

[0066] In the pH detection area, add 2 μL of universal indicator to the detection area;

[0067] After the reagents in the glucose detection area and pH detection area are modified, a layer of medical-grade double-sided tape with two circular openings and a color reference label are attached to the back of the paper chip layer with the reagents fixed, and then aligned and attached to form a complete sensor patch.

[0068] Example 2: Reaction conditions for nanozymes

[0069] This embodiment aims to explore the potential effects of mild reaction temperature and prolonged reaction time on the crystallinity and catalytic activity of nanozymes.

[0070] The difference between this embodiment and Example 1 is that the preparation conditions of the Prussian blue analog nanozyme in S1 are as follows: the pH value of the reaction system is adjusted to 1.0, the water bath reaction temperature is adjusted to 85°C, and the magnetic stirring reaction time is extended to 15 h. The remaining steps are exactly the same as in Example 1.

[0071] Example 3: Optimization of the proportion of main reaction raw materials for nanozymes

[0072] This embodiment aims to investigate the effects of reactant concentration and stabilizer dosage on nanozyme particle size, dispersibility, and final catalytic performance.

[0073] The difference between this embodiment and Example 1 is that the proportions of the main reaction raw materials were adjusted in S1: the concentration of sodium ferrocyanide was adjusted to 1.5 mmol / L, and the amount of polyvinylpyrrolidone was adjusted to 6 mg per 50 mL of reaction solution. The remaining steps are exactly the same as in Example 1.

[0074] Comparative Example 1: Au@Cu composite nanosheet nanoenzyme

[0075] The difference between this comparative example and Example 1 is that the nanozyme in the sensing patch is replaced with Au@Cu composite nanosheet nanozyme. The specific preparation method of Au@Cu composite nanosheet nanozyme is as follows.

[0076] 24 mg copper nitrate trihydrate, 400 μL 1.0 mol / L trifluoroacetic acid and 100 mg polyvinylpyrrolidone were dissolved in a mixture of 90 mL N,N-dimethylformamide and 30 mL ethanol to obtain the first mixture;

[0077] 4.4 mg of tetracarboxyphenylporphyrin iron was dissolved in a mixture of 30 mL N,N-dimethylformamide and 10 mL ethanol until completely dissolved to obtain a second mixture.

[0078] The second mixture was added dropwise to the first mixture; the mixture was then sonicated for 15 min and reacted at 80°C for 4 h.

[0079] The resulting mixture was centrifuged and washed twice with ethanol. After drying, the resulting solid was thoroughly ground into powder and redispersed in 100 mL of water.

[0080] Add 1 mL of 10 mmol / L chloroauric acid, stir well, then add 250 μL of 0.1 mmol / L sodium borohydride and centrifuge; wash twice with water, and redisperse in water to obtain Au@Cu composite nanosheet nanozyme.

[0081] Comparative Example 2: Prussian Blue (PB) prepared by the conventional dual-precursor co-precipitation method

[0082] The difference between this comparative example and Example 1 is that the preparation method of the Prussian blue analog nanozyme in step 1 is as follows:

[0083] Equal volumes of 1.7 mmol / L potassium ferricyanide solution and 1.7 mmol / L ferrous chloride tetrahydrate solution were slowly mixed with stirring.

[0084] Add 5 mg of polyvinylpyrrolidone and stir the reaction at room temperature for 1 h. Wash the product with water and ethanol alternately 6 times, collect the blue precipitate by centrifugation, dry the precipitate in a vacuum oven, and grind it to obtain Prussian blue nanozyme.

[0085] Comparative Example 3: Copper-Cobalt Bimetallic Prussian Blue Analog Nanozyme (CuCo-PBA)

[0086] The difference between this comparative example and Example 1 is that the preparation method of the Prussian blue analog nanozyme in step 1 is as follows:

[0087] Dissolve 0.85 mmol / L copper chloride dihydrate (final concentration) and 0.85 mmol / L cobalt chloride hexahydrate (final concentration) in 50 mL of 0.1 mol / L sodium chloride solution to obtain a third mixture;

[0088] Slowly add the solution dropwise to a volume equal to that of the third mixture of 1.7 mmol / L potassium ferricyanide solution while stirring, add 5 mg of polyvinylpyrrolidone, and stir at room temperature for 1 h;

[0089] The obtained product was washed six times with water and ethanol alternately, the precipitate was collected by centrifugation, dried under vacuum and then ground to obtain the final product.

[0090] Comparative Example 4: Replacement of Hydrophobic Barrier Material

[0091] The difference between this comparative example and Example 1 is that the freshly prepared PDMS in Example 1 is replaced with rosin ink.

[0092] Test case

[0093] 1. Nanozyme performance analysis

[0094] The effects of pH and temperature on the activity of sodium ferrocyanide-based peroxidases were systematically investigated. The enzyme-like activity of sodium ferrocyanide was studied using 3,3',5,5'-tetramethylbenzidine as a chromogenic substrate.

[0095] like Figure 2 As shown, neither hydrogen peroxide nor sodium ferrocyanide alone can induce a colorimetric reaction in 3,3',5,5'-tetramethylbenzidine. When all three are present, sodium ferrocyanide can effectively catalyze the oxidation of the colorimetric substrate by hydrogen peroxide to generate a blue product. The absorbance at 652 nm gradually increases with the increase of the concentration of the Prussian blue analogue. This indicates that the Prussian blue analogue nanozyme prepared in Example 1 of this invention has excellent peroxidase-like activity.

[0096] like Figure 3 As shown in (a), the Prussian blue analog nanozyme prepared in Example 1 exhibited the highest peroxidase-like activity at pH 4.0; simultaneously, as Figure 3 As shown in (b), the catalytic activity of the Prussian blue analogue first increased and then decreased as the temperature rose from 20 °C to 80 °C, reaching a maximum at 50 °C; the long-term catalytic stability of the Prussian blue analogue was evaluated by monitoring its activity for 25 consecutive days.

[0097] like Figure 4 The results showed that the catalytic activity of the Prussian blue analogue remained above 95% within 25 days, indicating its excellent long-term stability.

[0098] 2. Long-term stability testing of sensor patches

[0099] The sensor patch prepared in Example 1 was placed in an environment of 4°C and 50±2% humidity, and the signal changes of the sensor were detected over 15 days using a reagent with pH 7.0 and a glucose concentration of 100μM.

[0100] like Figure 5 As shown, the sensor patch prepared in Example 1 was used to analyze sweat, and its relative standard deviation was within 5% within 15 days. This indicates that the sensor patch has good detection stability. The stability advantage of the nanozyme comes from its inorganic and rigid structural nature, which avoids the inherent weaknesses of natural enzyme proteins, such as easy denaturation, easy degradation, and intolerance to harsh environments.

[0101] 3. Actual testing of human sweat

[0102] This invention provides a sensor patch that can be directly applied to the skin surface of volunteers for real-time monitoring of glucose and pH values ​​in sweat. Five healthy volunteers were recruited, and the sensor patches prepared in Examples 1-3 and Comparative Examples 1-4 were applied to their arms. During the test, volunteers underwent 45 minutes of running to induce sweating. 15 minutes after the exercise stopped, the color reference layer of the sensor patch was photographed using a smartphone, and the grayscale values ​​of the glucose and pH detection areas were read. Three points were measured in each detection area, and the average value was calculated. Simultaneously, sweat samples were collected from the same location at the same time using a medical absorbent pad. After centrifugation, the supernatant was collected and analyzed using standard instruments as a standard control. The pH value of one part was measured using a precision pH meter (PHS-3C, Leici, China), and the glucose concentration of the other part was measured using a high-performance liquid chromatograph (Essentia LC-10A, Shimadzu, Japan). The data deviation results are shown in Table 1.

[0103] like Figure 6 and Figure 7 As shown, the pH value of the volunteers' sweat measured using the sensor patch ranged from 5.8 to 7.1, and the glucose concentration ranged from 65.2 to 98.4 μM.

[0104] Table 1 Comparison of sweat pH and glucose concentration test results

[0105] In summary, the glucose and pH values ​​measured by the sensing patch prepared in Example 1 showed minimal deviation from those measured by commercial instruments, demonstrating its accuracy and reliability in practical applications. Examples 2 and 3, through different reaction conditions or raw material ratios, also prepared high-performance nanozymes and sensing patches. Their key performance indicators, such as catalytic activity, stability, and detection accuracy, were quite similar to those of Example 1, proving that the nanozyme synthesis method of this invention has good process tolerance and optimization potential.

[0106] Furthermore, the nanozymes prepared in Comparative Examples 1 and 3 are complex, requiring multiple synthesis steps, and may suffer from problems such as distortion within the crystal framework and coordination defects. These defects introduce heterogeneous metals into the subsequent sensor patch preparation, affecting the uniformity and efficiency of subsequent detection. The Prussian blue nanozyme used in Comparative Example 2 may have low crystallinity and particle agglomeration due to rapid precipitation at room temperature, thus increasing detection bias and making its sensor patch less accurate than that of Example 1. Comparative Example 4 uses rosin ink instead of PDMS, and the average deviation of the detection results is relatively large. This indicates that PDMS, as a hydrophobic barrier material, has superior chemical inertness, flexibility, and physical isolation effects, effectively preventing reagent crosstalk between detection areas.

[0107] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A paper chip-based wearable colorimetric sweat sensing patch, characterized in that, This includes the paper chip layer, adhesive layer, and color reference label; The paper chip layer includes the substrate and a hydrophobic barrier formed on the substrate; The hydrophobic barrier divides the substrate surface into at least two physically isolated detection zones; At least one of the detection zones is a glucose detection zone, which is loaded with a detection reagent containing a chromogenic substrate, a nanozyme, and a glucose oxidase. At least one of the detection zones is a pH detection zone, which contains a detection reagent for detecting pH. The nanozyme is a Prussian blue analog nanozyme.

2. The wearable colorimetric sweat sensing patch based on a paper chip according to claim 1, characterized in that, The hydrophobic barrier is formed by ink direct writing technology, followed by molding with polydimethylsiloxane and then curing.

3. The wearable colorimetric sweat sensing patch based on a paper chip according to claim 1, characterized in that, The preparation method of the nanozyme is as follows: Sodium ferrocyanide was dissolved in sodium chloride solution, and then polyvinylpyrrolidone was added to dissolve it. Add hydrochloric acid until the reaction system becomes acidic, stir in a hot water bath, and cool to room temperature to obtain the product; washing; The precipitate is collected by centrifugation, dried, and ground to obtain the final product.

4. The wearable colorimetric sweat sensing patch based on a paper chip according to claim 1, characterized in that, In the preparation method of the nanozyme, the hot water bath stirring conditions are 85-95 ℃, and the stirring time is 8-12 h.

5. The wearable colorimetric sweat sensing patch based on a paper chip according to claim 1, characterized in that, The final concentration of sodium ferrocyanide in the reaction system is 1.5-1.7 mmol / L, and the final concentration of polyvinylpyrrolidone in the reaction system is 0.08-0.12 g / L.

6. The method for preparing a wearable colorimetric sweat sensor patch based on a paper chip according to any one of claims 1-5, characterized in that, Includes the following steps: Preparation of Prussian blue analog nanozymes; A hydrophobic barrier is constructed on the substrate, and after the detection area is formed, it is cured. The corresponding detection reagents are fixed on the detection area respectively; The paper chip layer, the adhesive layer, and the color reference label are aligned and bonded in sequence to assemble a complete sensor patch.

7. The method for preparing the wearable colorimetric sweat sensing patch based on a paper chip according to claim 6, characterized in that, The curing conditions for the hydrophobic barrier are 70-90 ℃ and heating for 0.5-2 h.

8. The method for preparing the wearable colorimetric sweat sensing patch based on a paper chip according to claim 1, characterized in that, The chromogenic substrate is any one of 3,3',5,5'-tetramethylbenzidine or 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt.

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