A flexible wearable sweat electrochemical sensor and sweat monitoring method and application

Abstract

The present invention discloses a flexible wearable electrochemical sweat sensor, comprising an electrochemical sweat sensor electrode device 1, a Bluetooth transmission device 2 and a personal mobile data terminal 3; the electrochemical sweat sensor electrode device 1 comprises a three-electrode system and an ion introduction electrode 8 printed on a flexible stretchable substrate 7, the ion introduction electrode 8 is modified with pilocarpine, and the working electrode 6 is modified with a polypeptide composite hydrogel. The conductive hydrogel of the present invention has good biocompatibility, high sensitivity, good flexibility and self-healing function. The present invention develops a new flexible self-healing material with good biocompatibility and good anti-pollution performance, and further constructs a lightweight wearable electronic sensor based on the new flexible material, and constructs a wireless radio chemical sweat sensor to observe the dynamic biochemical signals output in real time on a mobile phone, and is equipped with a drug-stimulated sweating device, which can also realize direct monitoring of biochemical molecules in sweat in a static state.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical sensors, and more specifically relates to a wireless flexible wearable sweat electrochemical sensor capable of in-situ monitoring, a sweat monitoring method and an application. Background Art

[0002] In recent years, wearable sensors have attracted much attention due to their great potential in monitoring vital signs. However, wearable sensors on the market mainly monitor physical signals such as heart rate, body temperature and humidity, and cannot provide deeper information at the molecular level. This gap creates an opportunity for non-invasive monitoring of human body fluids. Compared with body fluids such as blood, interstitial fluid, tears and urine, sweat is a promising but relatively untapped biological fluid. It is an important and valuable body fluid for non-invasive monitoring because it contains important markers related to human physiological state, including vitamin C, ascorbic acid, uric acid, glucose and lactic acid. Its composition changes dynamically with changes in health, stress and dietary status. According to literature reports, the basic correlation between chemical molecular levels in blood and sweat means that sweat analysis can replace blood analysis. Therefore, sweat analysis can provide continuous detection information and can be used for non-invasive detection of physiological health status and disease diagnosis and treatment. If it can be freed from the limitations of large-scale hospital equipment, the study of high-performance wearable sweat electrochemical sensors can achieve non-invasive, continuous, in-situ and intuitive monitoring of these markers, which is of great significance for the realization of "smart healthcare".

[0003] However, research on sweat monitoring currently faces many problems, mainly focusing on the following aspects:

[0004] One of the key challenges of sweat analysis is the lack of materials with high flexibility, high conductivity, high sensitivity, high biocompatibility and anti-pollution. At present, the vast majority of wearable sensor devices are built on hard and brittle rigid substrate 7 materials, which easily leads to problems such as untimely data monitoring and inaccurate output, and thus cannot accurately provide more biochemical information at the level of human metabolic molecules. Therefore, the development of flexible electrochemical sensors is a prerequisite for the development of high-performance wearable sweat electrochemical sensing devices. Most of the flexible sensors are based on flexible materials such as flexible metal materials, polymer elastomers and polymer films as substrates 7, and combined with conductive materials with active functions (such as metal nanowires, metal nanoparticles, graphene, carbon nanotubes, etc.), which can achieve the combination of flexibility and sensitivity functions. However, due to the inherent rigidity, easy pollution, short fatigue life and other shortcomings of such conductive materials with active functions, it is difficult to better fit with human skin and withstand the complex mechanical shapes of natural skin, such as twisting, bending, stretching and folding, which brings great challenges to the real practical application of wearable electronic devices. Unlike traditional conductive flexible materials, conductive hydrogels have a network structure similar to that of living tissues, and can exhibit physiological characteristics and mechanical properties similar to those of human skin and organs, such as biocompatibility, high stretchability and low modulus, making them one of the ideal flexible matrix materials for human-machine interfaces. Moreover, peptide hydrogel flexible materials, due to their complex three-dimensional network structure, are conducive to the dispersion of functional materials and can avoid the stacking of materials, thus improving the detection sensitivity of peptide-based composite materials.

[0005] In addition, the ideal flexible wearable sensor device for sweat analysis is preferably unprocessed, and can directly measure the biochemical indicators in it, which can be free from contamination and influence in sweat with complex components and usually small collection volume. A large number of coexisting chemical species in sweat can be adsorbed to the sensor interface to contaminate and passivate the electrode, resulting in reduced credibility of the test results and difficulty in realizing in-situ monitoring applications. At present, the easy contamination of electrodes is also one of the problems that need to be solved urgently.

[0006] The second key challenge of sweat analysis is the lack of wireless, miniature, highly integrated multifunctional flexible electronic devices. Compared with non-in-situ detection, sensors used for in-situ detection need to directly face complex and dynamic microenvironments, and need to challenge complex environments, diverse biological elements, and easy contamination of sensor elements. How to develop new flexible materials with good biocompatibility and anti-pollution properties, and further build lightweight wearable electronic sensors based on this new flexible material, and construct wireless sensors on mobile phones to observe the real-time output of dynamic biochemical signals to achieve direct detection of biochemical molecules in sweat has become a technical bottleneck that needs to be broken through in the marketization of wearable devices.

[0007] Therefore, how to develop an anti-pollution polypeptide hydrogel material with high flexibility, high sensitivity and comprehensive properties such as anti-pollution, and construct a micro-flexible wearable electrochemical sweat sensor based on this multifunctional material, and a sweat stimulation electrode attached, which can also transmit the biochemical sensing signals in sweat to the mobile phone interface through Bluetooth through a small Bluetooth transmission system for monitoring when the human body is in a static state is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0008] In view of this, the present invention provides a wireless flexible wearable sweat electrochemical sensor capable of in-situ monitoring, and a sweat monitoring method and application.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] A flexible wearable sweat electrochemical sensor comprises an electrochemical sweat sensor electrode device 1, a Bluetooth transmission device 2 and a personal mobile data terminal 3, wherein the Bluetooth transmission device 2 is connected to the electrochemical sweat sensor electrode device 1 via a line, and the Bluetooth transmission device 2 is connected to the personal mobile data terminal 3 via wireless communication;

[0011] The electrochemical sweat sensor electrode device 1 includes a counter electrode 4, a reference electrode 5, and a working electrode 6 printed on a flexible stretchable substrate 7, and the working electrode 6 is modified with a polypeptide composite hydrogel. The polypeptide composite hydrogel includes a polypeptide, Au NPs and MoS2. The amino acid sequence of the polypeptide is (hydrophobic group)-Lys-(hydrophobic group)-(Lys-NH2)-(Phe-COOH), and Lys and Phe are both D-type amino acids.

[0012] Furthermore, the electrochemical sweat sensor electrode device 1 includes an ion introduction electrode 8 printed on a flexible stretchable substrate 7 , and the ion introduction electrode 8 is modified with pilocarpine.

[0013] Furthermore, the above-mentioned flexible stretchable substrate 7 is a TPU flexible stretchable substrate 7.

[0014] Furthermore, the material of the flexible stretchable substrate 7 may also be PC film or textile fabric.

[0015] Furthermore, the manufacturer of the above-mentioned TPU flexible stretchable substrate 7 is DuPont, and the model number is TL644-TE-11C.

[0016] Furthermore, the printing method is screen printing, inkjet printing or etching microfluidics.

[0017] Further, the above hydrophobic group is

[0018] One or both of the following.

[0019] A further beneficial effect of the above is that the hydrophobic groups are conducive to self-assembly into hydrogels.

[0020] Furthermore, the paste used for printing the reference electrode 5 is a stretchable silver paste, and the paste used for printing the working electrode 6 and the counter electrode 4 is a stretchable carbon paste.

[0021] Furthermore, the manufacturer of the above-mentioned stretchable silver paste is Engineered Materials Systems, Inc, and the model is CI-1036; the manufacturer of the above-mentioned stretchable carbon paste is Engineered Materials Systems, Inc, and the model is CI-2062.

[0022] A further beneficial effect of the above is that the stretchable printing paste has good stability and stretchability.

[0023] Furthermore, the personal mobile data terminal 3 is a smart phone or a tablet computer.

[0024] Furthermore, the preparation method of the above polypeptide composite hydrogel comprises the following steps:

[0025] (1) NaBH4 is added to water and dissolved in an ice bath to obtain an icy NaBH4 aqueous solution, and the HAuCl4·H2O aqueous solution is dropped into the MoS2 aqueous solution and stirred, and then the newly prepared icy NaBH4 aqueous solution is added under stirring, and the stirring is continued at room temperature, centrifuged, washed, and dried to obtain AuNPs / MoS2;

[0026] (2) The above polypeptide powder is dissolved in dimethyl sulfoxide to obtain a polypeptide original solution, and then the AuNPs / MoS2 aqueous solution is added and mixed evenly, and the mixture is allowed to stand to obtain an AuNPs / MoS2 / D-Pep hydrogel.

[0027] Furthermore, in the above step (1), the concentration of the glacial NaBH4 aqueous solution is 10-20 mol / L, the concentration of the HAuCl4·H2O aqueous solution is 10-20 mmol / L, the concentration of the MoS2 aqueous solution is 10-50 mg / mL, and the volume ratio of the glacial NaBH4 aqueous solution, the HAuCl4·H2O aqueous solution and the MoS2 aqueous solution is 1:1:100.

[0028] Furthermore, in the above step (1), the stirring speed is 200-500 r / min, and the HAuCl4·H2O aqueous solution is dripped into the MoS2 aqueous solution and stirred for 10-30 min, and stirring is continued at room temperature for 8-12 h.

[0029] Furthermore, in the above step (1), the dropping speed is 10-20 drops / min.

[0030] Furthermore, in the above step (1), the ice bath time is 5-10 min.

[0031] Furthermore, in the above step (1), the centrifugal speed is 8000-10000 r / min, and the centrifugal time is 5-10 min.

[0032] Furthermore, in the above step (1), ethanol and water are used for washing three times respectively.

[0033] Furthermore, in the above step (1), the drying temperature is 30-50° C. and the drying time is 5-8 hours.

[0034] Furthermore, in the above step (2), the concentration of the original polypeptide solution is 150 mg / mL, the concentration of the AuNPs / MoS2 aqueous solution is 2-10 mg / mL, and the volume ratio of the original polypeptide solution and the Au NPs / MoS2 aqueous solution is 35:965.

[0035] Furthermore, in the above step (2), the standing time is 0.2-0.5h.

[0036] The present invention also provides a method for monitoring sweat using the above-mentioned flexible wearable sweat electrochemical sensor, comprising the following steps:

[0037] 1) 7-10 μL of polypeptide composite hydrogel is modified on the surface of the working electrode 6. The polypeptide composite hydrogel modified on the surface of the working electrode 6 is used to absorb and store sweat. Sweat serves as a natural electrolyte.

[0038] 2) Clean the skin by rubbing with isopropyl alcohol, and fix the above-mentioned flexible wearable sweat electrochemical sensor on the human epidermis with medical double-sided tape;

[0039] 3) The AA and UA in sweat were scanned by differential pulse voltammetry in the potential range of 0.4-0.8 V, amplitude of 50 mV, and pulse width of 0.05 s;

[0040] 4) Monitoring AA and UA in sweat by time-current technique at the optimal potentials of 0.3 V and 0.5 V, respectively;

[0041] 5) The sweat monitoring signal is transmitted to the personal mobile data terminal 3 via the Bluetooth transmission device 2.

[0042] Furthermore, the method for monitoring sweat using the above-mentioned flexible wearable sweat electrochemical sensor further includes the following steps:

[0043] 6) cutting agarose gel into the same size as the ion introduction electrode 8 and decorating the anode and cathode sides of the ion introduction electrode 8. The preparation method of agarose hydrogel is as follows: dissolving 0.4-1.0g agarose in 10-25mL of 0.1mol / L potassium phosphate buffer, the pH of the potassium phosphate buffer is 7.0, stirring continuously at 170°C until the agarose is completely dissolved, and finally pouring the agarose gel into a mold and cooling to room temperature;

[0044] 7) Before stimulating sweat, the agarose hydrogel is modified on the electrode interface by a drop coating method to construct an ion introduction electrode. After freeze-drying, a 3-5wt% pilocarpine solution is dropped into the anode agarose hydrogel and stored for 1-2 hours. The positively charged pilocarpine drug is contained in the agarose hydrogel. After power is turned on, the pilocarpine drug is repelled from the anode part due to the charge repulsion, and the pilocarpine is repelled close to the skin part, and then sweating is stimulated.

[0045] The present invention also provides application of the above-mentioned flexible wearable sweat electrochemical sensor or the above-mentioned method for monitoring sweat in vital signs monitoring.

[0046] The beneficial effects of the present invention are:

[0047] 1) Before the existing electrochemical sensor detection, the test sample needs to be pre-treated to remove most of the substances that will contaminate the electrode, and then the detection is carried out; however, the present invention does not treat sweat, and can directly measure the biochemical indicators therein, which can be protected from contamination and influence in sweat with complex components and usually small collection volume.

[0048] 2) Conductive materials with active functions modified at the electrode interface (such as metal nanowires, metal nanoparticles, graphene, carbon nanotubes, etc.) have inherent disadvantages such as high rigidity, easy pollution, and short fatigue life. It is difficult to better fit with human skin and withstand the complex mechanical shapes of natural skin such as twisting, bending, stretching and folding, which brings great challenges to the real practical application of wearable electronic devices. The conductive hydrogel of the present invention has good biocompatibility, high sensitivity, good flexibility and self-healing function.

[0049] 3) Currently, there is a lack of highly integrated, lightweight, and compact electrochemical sweat sensors for monitoring human biochemical indicators that can be directly monitored on mobile phones. The present invention develops a flexible new material with good biocompatibility and anti-pollution performance, and further constructs a lightweight wearable electronic sensor based on the new flexible material, and constructs a wireless radio chemical sweat sensor to observe the dynamic biochemical signals output in real time on the mobile phone, and is equipped with a drug-stimulated sweating device, which can also realize direct monitoring of biochemical molecules in sweat in a static state. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1Schematic diagram of the structure of a flexible wearable sweat electrochemical sensor, wherein: 1-electrochemical sweat sensor electrode device, 2-Bluetooth transmission device, 3-personal mobile data terminal;

[0051] Figure 2 Schematic diagram of the counter electrode, reference electrode and working electrode of the electrochemical sweat sensor electrode device 1, wherein 4 is the counter electrode, 5 is the reference electrode, 6 is the working electrode, and 7 is the flexible stretchable substrate;

[0052] Figure 3 Schematic diagram of the principle of ion introduction electrodes assembled in the electrochemical sweat sensor electrode device 1 for stimulating sweating, wherein 8 - ion introduction electrode;

[0053] Figure 4 Schematic diagram and actual picture of the structure of polypeptide composite hydrogel material;

[0054] Figure 5 Effect diagram of the self-healing function of polypeptide composite hydrogel material;

[0055] Figure 6 A physical picture of the electrochemical sweat sensor electrode device 1;

[0056] Figure 7 Physical picture of the flexible wearable electrochemical sensor being stretched longitudinally;

[0057] Figure 8 When the electrochemical sweat sensor electrode device 1 is longitudinally stretched by 20%, the electrochemical IT signal diagrams after being stretched 200, 400, 600, 800 and 1000 times respectively;

[0058] Fig. 9 Actual picture of the flexible wearable electrochemical sensor being stretched laterally;

[0059] Fig.10 When the electrochemical sweat sensor electrode device 1 is stretched by 20% in the transverse direction, the electrochemical IT signal diagrams after being stretched for 200, 400, 600, 800 and 1000 times respectively;

[0060] Fig.11 Flexible wearable sweat electrochemical sensor for 5.0 mM [Fe(CN)6] in 100% sweat 3- / 4- DPV response diagram of;

[0061] Fig.12 DPV signal response diagram of the flexible wearable sweat electrochemical sensor for the detection of uric acid (UA) and vitamin C (AA) in 100% sweat;

[0062] Fig.13 IT signal response diagram of the flexible wearable sweat electrochemical sensor monitoring uric acid (UA) in 100% sweat. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] The polypeptide of the present invention was commissioned to Hefei Guopeptide Biotechnology Co., Ltd. to prepare according to the amino acid sequence of the polypeptide of the present invention.

[0065] The manufacturer of the TPU flexible stretchable substrate 7 in the embodiment is DuPont, and the model number is TL644-TE-11C.

[0066] The manufacturer of the stretchable silver paste is Engineered Materials Systems, Inc, and the model is CI-1036; the manufacturer of the stretchable carbon paste is Engineered Materials Systems, Inc, and the model is CI-2062.

[0067] Example 1

[0068] like Figure 1 As shown, the flexible wearable sweat electrochemical sensor comprises an electrochemical sweat sensor electrode device (1), a Bluetooth transmission device (2) and a personal mobile data terminal (3) smart phone, wherein the Bluetooth transmission device (2) is connected to the electrochemical sweat sensor electrode device (1) via a line, and the Bluetooth transmission device (2) is connected to the smart phone via wireless communication;

[0069] like Figure 2 and Figure 3 As shown, the electrochemical sweat sensor electrode device (1) includes a counter electrode (4), a reference electrode (5), a working electrode (6) and an ion introduction electrode (8) screen-printed on a TPU flexible stretchable substrate (7), the ion introduction electrode (8) is modified with pilocarpine, and the working electrode (6) is modified with a polypeptide composite hydrogel, the polypeptide composite hydrogel includes a polypeptide, AuNPs and MoS2, the amino acid sequence of the polypeptide is (Nap)-Lys-(Nap)-(Lys-NH2)-(Phe-COOH), and Lys and Phe are both D-type amino acids.

[0070] The electrochemical sweat sensor electrode device (1) includes a counter electrode (4), a reference electrode (5), a working electrode (6) and an ion introduction electrode (8) screen-printed on a TPU flexible stretchable substrate (7) using a slurry. The slurry used for printing the reference electrode (5) is a stretchable silver paste, and the slurry used for printing the working electrode (6) and the counter electrode (4) is a stretchable carbon paste. The ion introduction electrode (8) is modified with pilocarpine, which can be released to the skin surface when the electrode is energized to stimulate sweating. The working electrode (6) is modified with a polypeptide composite hydrogel, which has a natural sweat absorbent and is used to store sweat, such as Figure 5 As shown, the polypeptide composite hydrogel has self-healing properties, good conductivity and selective catalytic function for vitamin C and uric acid in sweat.

[0071] like Figure 6 As shown in the figure, it is a physical picture of the electrochemical sweat sensor electrode device (1), wherein the key point is the electrochemical sweat sensor electrode part. The electrode part is screen-printed with a three-electrode system and an ion introduction electrode (8) on a flexible and stretchable substrate (7) TPU.

[0072] like Figure 7-Figure 10 As shown, the TPU flexible stretchable substrate (7) has good flexibility and stretchability, and the stretchable printing paste also has good stability and stretchability. After being stretched by 20% in the transverse and longitudinal directions respectively, there is no effect on the electron transfer effect of the working electrode (6). In addition, the polypeptide composite hydrogel modified on the working electrode (6) is the core and innovation point of the entire flexible wearable sweat electrochemical sensor. The composite multifunctional material has self-healing properties and can adapt to the twisting, bending, stretching and folding movements of the skin. It can better transfer electrons, as well as exert its good conductivity and high specificity catalytic function for vitamin C and uric acid in sweat. The MoS2 two-dimensional nanomaterial in the polypeptide composite hydrogel is combined with the hydrophobic part of the polypeptide due to a large amount of π-π stacking, so that the polypeptide composite hydrogel material has a self-healing function.

[0073] The amino acid sequence of the polypeptide is (Nap)-Lys-(Nap)-(Lys-NH2)-(Phe-COOH), (Lys and Phe are both D-type amino acids, and the hydrophobic group is

[0074] The preparation method of the polypeptide composite hydrogel comprises the following steps:

[0075] (1) NaBH4 was added to water and dissolved in an ice bath for 5 min to obtain a 10 mol / L glacial NaBH4 aqueous solution. 100 μL of a 10 mmol / L HAuCl4·H2O aqueous solution was dropped into a 10 mL 10 mg / mL MoS2 aqueous solution and stirred for 10 min at a dropping speed of 10 drops / min. Then, 100 μL of the newly prepared glacial NaBH4 aqueous solution was added under stirring. The stirring was continued at room temperature for 8 h. The mixture was centrifuged at a speed of 8000 r / min for 5 min. The mixture was washed three times with ethanol and water respectively and dried at a drying temperature of 30°C for 6 h to obtain AuNPs / MoS2.

[0076] (2) 150 mg of polypeptide powder was dissolved in dimethyl sulfoxide to obtain 1 mL of a polypeptide original solution with a concentration of 150 mg / mL. 35 μL of the polypeptide original solution was taken out, and then 965 μL of an aqueous solution of Au NPs / MoS2 composite nanomaterials with a concentration of 2 mg / mL was added thereto. The mixture was mixed evenly and allowed to stand for 0.5 h to obtain AuNPs / MoS2 / D-Pep hydrogel.

[0077] The method for monitoring sweat using a flexible wearable sweat electrochemical sensor comprises the following steps:

[0078] 1) cutting agarose gel into the same size as the ion introduction electrode (8) and modifying it on both sides of the anode and cathode of the ion introduction electrode (8), the preparation method of agarose hydrogel is: dissolving 0.4 agarose in 10 mL of 0.1 mol / L potassium phosphate buffer, the pH of the potassium phosphate buffer is 7.0, stirring continuously at 170° C. until the agarose is completely dissolved, and finally pouring the agarose gel into a mold and cooling it to room temperature;

[0079] 2) Before stimulating sweat, the agarose hydrogel is modified on the electrode interface by a drop coating method to construct an ion introduction electrode. After freeze-drying, a 3wt% pilocarpine solution is dropped into the anode agarose hydrogel and stored for 1 hour. The positively charged pilocarpine drug is contained in the agarose hydrogel. After power is turned on, the pilocarpine drug is repelled from the anode site due to charge repulsion, and the pilocarpine is repelled close to the skin site, thereby stimulating sweating.

[0080] 3) 10 μL of polypeptide composite hydrogel is modified on the surface of the working electrode (6). The polypeptide composite hydrogel modified on the surface of the working electrode (6) is used to absorb and store sweat. Sweat serves as a natural electrolyte.

[0081] 4) Clean the skin by rubbing with isopropyl alcohol, and fix a flexible wearable sweat electrochemical sensor on the human epidermis with medical double-sided tape;

[0082] 5) Using differential pulse voltammetry, AA and UA in sweat were scanned in the potential range of 0.4-0.8 V, amplitude of 50 mV, and pulse width of 0.05 s;

[0083] 6) Monitor AA and UA in sweat by time-current technique at the optimal potentials of 0.3 V and 0.5 V, respectively;

[0084] 7) The sweat monitoring signal is transmitted to the personal mobile data terminal (3) via the Bluetooth transmission device (2).

[0085] 1. Electrode construction process: 10 μL of polypeptide composite hydrogel was modified onto the flexible printed electrode interface by drop coating to construct a flexible electrochemical sensor based on the composite hydrogel.

[0086] Evaluation of antifouling performance: The antifouling performance of different modified electrode surfaces was evaluated in a pure protein environment using pure proteins of BSA, Lys, and Mb (negatively charged, positively charged, and neutrally charged, respectively). In addition, the antifouling performance of the sensor was tested in a complex environment (human sweat), and the differential pulse voltammetry (DPV) signal change rate was recorded before and after 0.5h of immersion in samples of different concentrations of protein and human sweat to evaluate the short-term antifouling performance. At the same time, a long-term antifouling test of 20 days was carried out using 100% human sweat. Fig.11 As shown in the figure, the anti-pollution performance of the sensor was tested in a complex environment (human sweat), and the 5.0 mM [Fe(CN)6] 3- / 4- The DPV response of the present invention was studied. The results showed that the DPV signal remained unchanged with the increase of sweat content, indicating that the polypeptide composite hydrogel of the present invention has good short-term antifouling performance.

[0087] Sensing test: The potential range is set to 0.4-0.8V, the amplitude is 50mV, and the pulse width is 0.05s. The catalytic performance and specificity of the flexible electrochemical sensor for markers such as vitamin C and uric acid in PBS (0.2M, pH 7.0) buffer solution are investigated by differential pulse voltammetry (DPV), and different concentrations of vitamin C and uric acid are measured by time-current technology (IT technology) under the conditions of optimal potentials of 0.3V and 0.5V respectively; finally, the electrochemical sensor uses IT technology to monitor vitamin C and uric acid in human sweat, and transmits the monitoring signal to the mobile phone through a Bluetooth device to realize home monitoring of human metabolic function.

[0088] like Fig.12As shown in the figure, the DPV signal response diagram of the wearable sweat electrochemical sensor based on polypeptide composite hydrogel for the detection of uric acid (UA) and vitamin C (AA) in 100% sweat, where the response potential of AA is about 0.3V and the response potential of UA is about 0.55V. Fig.13 As shown, the IT response diagram of the wearable sweat electrochemical sensor based on AuNPs / MoS2 / D-Pep hydrogel flexible material to 100% UA in sweat at 0.55V respectively. The results show that the sensor has good and stable response ability for monitoring UA in sweat.

[0089] Example 2

[0090] The amino acid sequence of the polypeptide is (Fomc)-Lys-(Fomc)-(Lys-NH2)-(Phe-COOH), Lys and Phe are both D-type amino acids, and the hydrophobic group is

[0091] The preparation method of the polypeptide composite hydrogel comprises the following steps:

[0092] (1) NaBH4 was added to water and dissolved in an ice bath for 8 min to obtain a 15 mol / L glacial NaBH4 aqueous solution. 100 μL of a 15 mmol / L HAuCl4·H2O aqueous solution was dropped into a 10 mL 30 mg / mL MoS2 aqueous solution and stirred for 20 min at a dropping speed of 15 drops / min. Then, 100 μL of the newly prepared glacial NaBH4 aqueous solution was added under stirring. Stirring was continued at room temperature for 10 h. The mixture was centrifuged at a speed of 9000 r / min for 8 min. The mixture was washed three times with ethanol and water respectively and dried at a drying temperature of 40°C for 5 h to obtain AuNPs / MoS2.

[0093] (2) 150 mg of polypeptide powder was dissolved in dimethyl sulfoxide to obtain 1 mL of a polypeptide original solution with a concentration of 150 mg / mL. 35 μL of the polypeptide original solution was taken out, and then 965 μL of an AuNPs / MoS2 nanocomposite aqueous solution with a concentration of 7 mg / mL was added thereto. The mixture was mixed evenly and allowed to stand for 0.4 h to obtain an Au NPs / MoS2 / D-Pep hydrogel.

[0094] The method for monitoring sweat using a flexible wearable sweat electrochemical sensor comprises the following steps:

[0095] 1) cutting agarose gel into the same size as the ion introduction electrode (8) and modifying it on both sides of the anode and cathode of the ion introduction electrode (8), the preparation method of agarose hydrogel is: dissolving 0.8g of agarose in 15mL of 0.1mol / L potassium phosphate buffer, the pH of the potassium phosphate buffer is 7.0, stirring continuously at 170°C until the agarose is completely dissolved, and finally pouring the agarose gel into a mold and cooling it to room temperature;

[0096] 2) Before stimulating sweat, the agarose hydrogel is modified on the electrode interface by a drop coating method to construct an ion introduction electrode. After freeze-drying, a 4wt% pilocarpine solution is dropped into the anode agarose hydrogel and stored for 1.5 hours. The positively charged pilocarpine drug is contained in the agarose hydrogel. After power is turned on, the pilocarpine drug is repelled from the anode site due to charge repulsion, and the pilocarpine is repelled close to the skin site, thereby stimulating sweating.

[0097] 3) 9 μL of polypeptide composite hydrogel is modified on the surface of the working electrode (6). The polypeptide composite hydrogel modified on the surface of the working electrode (6) is used to absorb and store sweat. Sweat serves as a natural electrolyte.

[0098] 4) Clean the skin by rubbing with isopropyl alcohol, and fix a flexible wearable sweat electrochemical sensor on the human epidermis with medical double-sided tape;

[0099] 5) Using differential pulse voltammetry, AA and UA in sweat were scanned in the potential range of 0.4-0.8 V, amplitude of 50 mV, and pulse width of 0.05 s;

[0100] 6) Monitor AA and UA in sweat by time-current technique at the optimal potentials of 0.3 V and 0.5 V, respectively;

[0101] 7) The sweat monitoring signal is transmitted to the personal mobile data terminal (3) via the Bluetooth transmission device (2).

[0102] Example 3

[0103] The amino acid sequence of the polypeptide is (Pyrene)-Lys-(Pyrene)-(Lys-NH2)-(Phe-COOH), Lys and Phe are both D-type amino acids, and the hydrophobic group is

[0104] The preparation method of the polypeptide composite hydrogel comprises the following steps:

[0105] (1) NaBH4 was added to water and dissolved in an ice bath for 10 min to obtain a 20 mol / L glacial NaBH4 aqueous solution. 100 μL of a 20 mmol / L HAuCl4·H2O aqueous solution was dropped into a 10 mL 50 mg / mL MoS2 aqueous solution and stirred for 30 min at a dropping speed of 20 drops / min. Then, 100 μL of the newly prepared glacial NaBH4 aqueous solution was added under stirring. Stirring was continued at room temperature for 12 h. The mixture was centrifuged at a speed of 10000 r / min for 10 min. The mixture was washed three times with ethanol and water respectively and dried at a drying temperature of 50°C for 8 h to obtain AuNPs / MoS2.

[0106] (2) 150 mg of polypeptide powder was dissolved in dimethyl sulfoxide to obtain 1 mL of 150 mg / mL polypeptide original solution, 35 μL of the polypeptide original solution was taken out, and then 965 μL of 10 mg / mL AuNPs / MoS2 nanocomposite aqueous solution was added thereto, mixed evenly, and allowed to stand for 0.2 h to obtain Au NPs / MoS2 / D-Pep hydrogel.

[0107] The method for monitoring sweat using a flexible wearable sweat electrochemical sensor comprises the following steps:

[0108] 1) cutting agarose gel into the same size as the ion introduction electrode (8) and modifying it on both sides of the anode and cathode of the ion introduction electrode (8), the preparation method of agarose hydrogel is: dissolving 1.0g agarose in 25mL of 0.1mol / L potassium phosphate buffer, the pH of the potassium phosphate buffer is 7.0, stirring continuously at 170°C until the agarose is completely dissolved, and finally pouring the agarose gel into a mold and cooling it to room temperature;

[0109] 2) Before stimulating sweat, the agarose hydrogel is modified on the electrode interface by a drop coating method to construct an ion introduction electrode. After freeze-drying, a 5wt% pilocarpine solution is dropped into the anode agarose hydrogel and stored for 2 hours. The positively charged pilocarpine drug is contained in the agarose hydrogel. After power is turned on, the pilocarpine drug is repelled from the anode site due to charge repulsion, and the pilocarpine is repelled close to the skin site, thereby stimulating sweating.

[0110] 3) 7 μL of polypeptide composite hydrogel is modified on the surface of the working electrode (6). The polypeptide composite hydrogel modified on the surface of the working electrode (6) is used to absorb and store sweat. Sweat serves as a natural electrolyte.

[0111] 4) Clean the skin by rubbing with isopropyl alcohol, and fix a flexible wearable sweat electrochemical sensor on the human epidermis with medical double-sided tape;

[0112] 5) Using differential pulse voltammetry, AA and UA in sweat were scanned in the potential range of 0.4-0.8 V, amplitude of 50 mV, and pulse width of 0.05 s;

[0113] 6) Monitor AA and UA in sweat by time-current technique at the optimal potentials of 0.3 V and 0.5 V, respectively;

[0114] 7) The sweat monitoring signal is transmitted to the personal mobile data terminal (3) via the Bluetooth transmission device (2).

[0115] The disclosed embodiments are described to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flexible wearable sweat electrochemical sensor, characterized in that: It comprises an electrochemical sweat sensor electrode device (1), a Bluetooth transmission device (2) and a personal mobile data terminal (3), wherein the Bluetooth transmission device (2) is connected to the electrochemical sweat sensor electrode device (1) via a line, and the Bluetooth transmission device (2) is connected to the personal mobile data terminal (3) via wireless communication; The electrochemical sweat sensor electrode device (1) comprises a counter electrode (4), a reference electrode (5), and a working electrode (6) printed on a flexible stretchable substrate (7); the working electrode (6) is modified with a polypeptide composite hydrogel, the polypeptide composite hydrogel comprising a polypeptide, AuNPs, and MoS2; the amino acid sequence of the polypeptide is (hydrophobic group)-Lys-(hydrophobic group)-(Lys-NH2)-(Phe-COOH), and Lys and Phe are both D-type amino acids; The hydrophobic group is One or both of the following.

2. A flexible wearable sweat electrochemical sensor according to claim 1, characterized in that: The preparation method of the polypeptide composite hydrogel comprises the following steps: (1) NaBH4 is added to water and dissolved in an ice bath to obtain an icy NaBH4 aqueous solution, and the HAuCl4·H2O aqueous solution is dropped into the MoS2 aqueous solution and stirred, and then the newly prepared icy NaBH4 aqueous solution is added under stirring, and the stirring is continued at room temperature, centrifuged, washed, and dried to obtain AuNPs / MoS2; (2) The polypeptide powder of claim 1 is dissolved in dimethyl sulfoxide to obtain a polypeptide original solution, and then the AuNPs / MoS2 aqueous solution is added and mixed evenly, and the mixture is allowed to stand to obtain an AuNPs / MoS2 / D-Pep hydrogel.

3. A flexible wearable sweat electrochemical sensor according to claim 2, characterized in that: In the step (1), the concentration of the glacial NaBH4 aqueous solution is 10-20 mol / L, the concentration of the HAuCl4·H2O aqueous solution is 10-20 mmol / L, the concentration of the MoS2 aqueous solution is 10-50 mg / mL, and the volume ratio of the glacial NaBH4 aqueous solution, the HAuCl4·H2O aqueous solution and the MoS2 aqueous solution is 1:1:

100.

4. A flexible wearable sweat electrochemical sensor according to claim 2, characterized in that: In the step (1), the stirring speed is 200-500 r / min, and the HAuCl4·H2O aqueous solution is dripped into the MoS2 aqueous solution and stirred for 10-30 min, and the stirring is continued at room temperature for 8-12 h.

5. A flexible wearable sweat electrochemical sensor according to claim 2, characterized in that: In the step (2), the concentration of the original polypeptide solution is 150 mg / mL, the concentration of the Au NPs / MoS2 aqueous solution is 2-10 mg / mL, and the volume ratio of the original polypeptide solution to the AuNPs / MoS2 aqueous solution is 35:

965.

6. A flexible wearable sweat electrochemical sensor according to claim 1, characterized in that: The slurry used for printing the reference electrode (5) is a stretchable silver paste, and the slurry used for printing the working electrode (6) and the counter electrode (4) is a stretchable carbon paste.

7. The flexible wearable sweat electrochemical sensor according to claim 1, characterized in that: The personal mobile data terminal (3) is a smart phone or a tablet computer.

8. A method for monitoring sweat using a flexible wearable sweat electrochemical sensor according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1) 7-10 μL of polypeptide composite hydrogel is modified on the surface of the working electrode (6), and the polypeptide composite hydrogel modified on the surface of the working electrode (6) is used to absorb and store sweat, and the sweat serves as a natural electrolyte; 2) Cleaning the skin by rubbing with isopropyl alcohol, and fixing the flexible wearable sweat electrochemical sensor on the human epidermis with medical double-sided tape; 3) The AA and UA in sweat were scanned by differential pulse voltammetry in the potential range of 0.4-0.8 V, amplitude of 50 mV, and pulse width of 0.05 s; 4) Monitoring AA and UA in sweat by time-current technique at the optimal potentials of 0.3 V and 0.5 V, respectively; 5) The sweat monitoring signal is transmitted to the personal mobile data terminal (3) via the Bluetooth transmission device (2).

9. Application of a flexible wearable sweat electrochemical sensor according to any one of claims 1 to 7 or a method for monitoring sweat according to claim 8 in vital sign monitoring.

Images