Wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme and preparation method of wearable sweat glucose detection system

Abstract

The invention discloses a wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme and a preparation method of the wearable sweat glucose detection system. The detection system comprises a sweat collection and sensing module, an electrochemical detection module and an iontophoresis module, the sweat collecting and sensing module comprises a micro-fluidic channel and a screen-printed electrode; the micro-fluidic channel is used for collecting sweat; the screen-printed electrode comprises a working electrode for detecting glucose, a counter electrode and a reference electrode to form a three-electrode system; wherein the working electrode for detecting the glucose is provided with a functional layer, and the functional layer is modified by multi-shell metal organic framework layered encapsulation enzyme for detecting the glucose and chitosan for fixing the multi-shell metal organic framework layered encapsulation enzyme; the electrochemical detection module is used for obtaining electrochemical sensing detection data; and the iontophoresis module is used for outputting an adjustable constant current source to enable iontophoresis to stimulate skin to sweat. The portable long-time continuous detection of sweat glucose can be realized, and the detection method is rapid and convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of blood glucose monitoring, and in particular to a wearable sweat glucose detection system based on a multi-shell metal organic framework encapsulated enzyme and a preparation method thereof. Background Art

[0002] At present, the methods of blood glucose monitoring mainly include biochemical blood glucose testing, self-blood glucose monitoring, continuous blood glucose monitoring and non-invasive blood glucose monitoring. Biochemical blood glucose testing has advantages in providing accurate blood glucose information, but its operation is complicated and usually needs to be performed in a clinical environment. Although self-blood glucose monitoring allows patients to monitor at home, it only provides single-point blood glucose information and cannot capture the full picture of blood glucose fluctuations. Although continuous blood glucose monitoring can provide continuous and comprehensive blood glucose data to help discover hidden hyperglycemia and hypoglycemia, it still requires piercing the skin and requires regular finger blood correction. Relatively speaking, non-invasive blood glucose monitoring uses a non-invasive method to obtain blood glucose information, eliminating problems such as pain and infection risks, providing patients with a more convenient and comfortable blood glucose monitoring method, helping to improve the quality of life, while reducing trauma and inconvenience, which is of great significance in diabetes management. Sweat is easier to obtain and the content of glucose, lactate, sodium, etc. in sweat is an indicator of electrolyte imbalance, cystic fibrosis, physiological stress, osteoporosis, bone mineral loss, etc. in the body, which can be used for non-invasive physiological health status detection and disease diagnosis and treatment. Summary of the invention

[0003] The purpose of the present invention is to propose a wearable sweat glucose detection system based on a multi-shell metal organic framework encapsulated enzyme and a preparation method thereof, which can realize portable, long-term continuous detection of sweat glucose, and the detection method is fast and convenient.

[0004] To achieve the above purpose, the technical solution provided by the present invention is:

[0005] A wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme, including a sweat collection and sensing module, an electrochemical detection module and an iontophoresis module;

[0006] The sweat collection and sensing module comprises a microfluidic channel and a screen-printed electrode; the microfluidic channel is used to collect sweat to collect the glucose concentration in the sweat in real time; the screen-printed electrode comprises a working electrode for detecting glucose, a counter electrode and a reference electrode, forming a three-electrode system; wherein the working electrode for detecting glucose has a functional layer, and the functional layer is modified by a multi-shell metal organic framework layered encapsulated enzyme for detecting glucose and chitosan for fixing the multi-shell metal organic framework layered encapsulated enzyme;

[0007] The electrochemical detection module is used to obtain electrochemical sensing detection data under a three-electrode system;

[0008] The iontophoresis module is used to output an adjustable constant current source so that iontophoresis stimulates the skin to sweat, and includes a cathode, an anode, a boost conversion module and a constant current source module; the boost conversion module is used to increase the extraction voltage of iontophoresis, and the constant current source module is used to output a constant current to the cathode and the anode.

[0009] To optimize the above technical solutions, the specific measures taken also include:

[0010] The microfluidic channel comprises a sweat accumulation layer, a sweat inlet layer and a microfluidic channel layer, and the screen-printed electrode comprises a printed electrode layer;

[0011] The sweat accumulation layer is attached to the skin of the person to be tested, and the sweat accumulation layer includes a sweat collection hole in the middle and surrounding holes for placing electroosmotic gel;

[0012] The sweat inlet layer is arranged on the sweat accumulation layer, and the sweat inlet layer comprises a sweat inlet hole and a hole for placing the electroosmotic gel;

[0013] The microfluidic channel layer is arranged on the sweat inlet layer, and the microfluidic channel layer includes a sweat collection chamber, a microfluidic channel sweat inlet hole, a microfluidic channel sweat outlet hole and a hole for placing an electroosmotic gel;

[0014] The printed electrode layer is provided with an electrode interface, and the electrode interface has holes for placing the electroosmotic gel.

[0015] Furthermore, the screen-printed electrode includes a working electrode for detecting pH; the electrode interface is equipped with a working electrode for detecting glucose, a working electrode for detecting pH, a reference electrode, a counter electrode, and a cathode and an anode of an iontophoresis module.

[0016] It also includes a Bluetooth Soc control and communication module, which includes a control system and a signal transmission module. The control system is used to control the system operation, and the signal transmission module is used to control the system and the transmission of electrical signals. The signal transmission module includes a Bluetooth function.

[0017] It also includes a power management module, which is used to provide charge and discharge protection for the system and provide a voltage that meets the accuracy requirements for the system circuit operation;

[0018] Furthermore, the power management module includes a lithium battery protection circuit, a lithium battery charging management circuit and a DC / DC power conversion circuit; the lithium battery protection circuit is used for charging overvoltage protection and discharging low voltage protection; the lithium battery charging management circuit is used to output a stable charging current, and when charging is completed, the charging current is reduced to the charging end threshold; the DC / DC power conversion circuit is used to convert the voltage output by the lithium battery into a stable voltage output that meets the accuracy requirements and provide it to the Bluetooth Soc control and communication module and the electrochemical detection module for use.

[0019] It also includes an APP module on the mobile terminal, which is connected to the Bluetooth Soc control and communication module through the mobile terminal by a Bluetooth signal to control the system settings and receive system data, convert the detection data into sweat glucose concentration value and pH value, and display the glucose detection concentration value, pH value and change curve in real time;

[0020] Furthermore, the Bluetooth Soc control and communication module includes an NRF52832 system module, an A / D module and a D / A module; the NRF52832 system module processes the collected signals and sends them to the mobile terminal where the APP module is located via Bluetooth; the A / D module is used to collect the voltage signal output by the electrochemical detection module; and the D / A module is used to output the voltage to control the constant potential of the three-electrode system.

[0021] The electrode interface is connected to a flexible connecting wire, and the flexible connecting wire is connected to the wiring port of the Bluetooth Soc control and communication module through an FPC soft cable connector.

[0022] The present invention also provides a preparation method of a wearable sweat glucose detection system based on a multi-shell metal organic framework encapsulated enzyme, wherein a sweat collection and sensing module is made by microfluidic channels and screen-printed electrodes; the sweat collection and sensing module, the electrochemical detection module and the ion electrophoresis module are integrated and installed into a wearable sweat glucose detection system; wherein the sweat collection and sensing module is arranged on one side of the detection system so as to be able to fit the skin, and is connected to the electrochemical detection module and the ion electrophoresis module.

[0023] The functional layer is modified by layered encapsulation of enzymes by a multi-shell metal organic framework, and the modification method is:

[0024] Activate and set aside a working electrode for detecting glucose; prepare a multi-shell metal organic framework layered encapsulated enzyme; and modify the working electrode for detecting glucose using the multi-shell metal organic framework layered encapsulated enzyme;

[0025] The preparation method of the sweat collection and sensing module is as follows:

[0026] In the sweat accumulation layer, sweat inlet layer, microfluidic channel layer and printed electrode layer, holes for placing electroosmotic gel are respectively formed by laser patterning; the sweat accumulation layer forms sweat collection holes by laser patterning; the sweat inlet layer forms sweat inlet holes by laser patterning; the microfluidic channel layer forms microfluidic channel sweat inlet holes, microfluidic channel sweat outlet holes, CBV ventilation valves and sweat collection chambers by laser patterning; the printed electrode layer is obtained by screen printing; the sweat accumulation layer, sweat inlet layer, microfluidic channel layer and printed electrode layer are assembled to obtain a sweat collection and sensing module.

[0027] The method for preparing a multi-shell metal organic framework hierarchical encapsulation enzyme is:

[0028] Mix 2-methylimidazole and CTAB and add GO x , Zn(NO3)2·6H2O, and the mixed reaction yielded GOX@ZIF-8;

[0029] GOX@ZIF-8 was mixed with 2-methylimidazole and CTAB, and HRP and Zn(NO3)2·6H2O were added to form a multi-shell metal-organic framework hierarchical encapsulation enzyme GOx@ZIF-8@HRP@ZIF-8;

[0030] The method of using a multi-shell metal organic framework to hierarchically encapsulate enzymes to modify the working electrode for detecting glucose is as follows:

[0031] The multi-shell metal organic framework layered encapsulated enzyme is evenly dispersed in the chitosan solution to obtain a mixed solution, and the mixed solution is drop-coated on the surface of the working electrode for detecting glucose and allowed to stand for 10-20 hours.

[0032] The method of using a multi-shell metal organic framework to hierarchically encapsulate enzymes to modify the working electrode for detecting glucose is as follows:

[0033] The multi-shell metal organic framework layered encapsulated enzyme is dispersed in chitosan solution and ultrasonically dispersed to obtain a mixed solution, which is then dripped on the surface of a working electrode for detecting glucose and allowed to stand for 10-20 hours; wherein the chitosan solution has a pH of 7.4 and a mass concentration of 0.05-5%.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention proposes a wearable sweat glucose detection system based on a multi-shell metal organic framework encapsulated enzyme, which implements iontophoresis to stimulate skin sweating by outputting an adjustable constant current source through an iontophoresis module, collects sweat through a sweat collection and sensing module including a microfluidic channel to collect the glucose concentration in sweat in real time, realizes glucose detection in a three-electrode system through screen-printed electrodes, and obtains electrochemical detection data through an electrochemical detection module.

[0036] The present invention also designs a Bluetooth Soc control and communication module to control the system and collect electrical signals, and has a Bluetooth transmission function to meet the wireless application of the device in a wearable scenario. The power management module provides charging and discharging protection for the system and provides high-precision voltage for circuit operation. The APP module can use a mobile terminal application based on Android and other systems to control and receive and save the data of the monitoring system through low-power Bluetooth, and display the glucose concentration in real time. The system adopts embedded design and flexible circuit technology to make it miniaturized and stretchable, and can realize portable and long-term continuous detection of sweat glucose, with low detection cost and fast and convenient detection method.

[0037] The wearable sweat glucose detection system of the present invention adopts a multi-shell metal organic framework encapsulated enzyme to modify the working electrode for detecting glucose. The multi-shell metal organic framework encapsulated enzyme has good stability and a wide detection range.

[0038] The detection system of the present invention has a simple structure and a manufacturing method, is easy to wear, and has a small size and light weight. Compared with other blood sugar detection methods at this stage, the detection cost is extremely low. The present invention can be portable and wearable and can perform detection anytime and anywhere, solving the problem of not using exercise, and generating sweat in a static state to make the detection effective, truly realizing closed-loop sweat glucose detection, and has high sensitivity and strong practicality, which is of great significance for the daily monitoring of diabetic patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of a wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzymes according to the present invention;

[0040] Figure 2 is a flow chart of a wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme of the present invention;

[0041] Figure 3 is a schematic diagram of a sweat collection and sensing module of the present invention;

[0042] Figure 4 is a schematic diagram of the screen-printed electrodes of the sweat collection and sensing module of the present invention;

[0043] Figure 5 is a structural diagram of a microfluidic channel module of a sweat collection and sensing module of the present invention;

[0044] Figure 6 This is the cyclic voltammogram of the multi-shell metal organic framework encapsulated enzyme glucose sensor prepared in Example 1 of the present invention.

[0045] Figure 7It is a linear relationship between the reduction peak value of the multi-shell metal organic framework encapsulated enzyme glucose sensor prepared in Example 1 of the present invention and the glucose concentration in the range of 0.2mM-1mM.

[0046] Figure 8 This is a graph showing the changes in peak current of the same electrode when testing a 20 μM glucose solution for 14 consecutive days.

[0047] In the figure: 1-printed electrode layer, 2-microfluidic channel layer, 3-sweat inlet layer, 4-sweat accumulation layer, 5-working electrode for detecting glucose, 6-working electrode for detecting pH, 7-reference electrode, 8-counter electrode, 9-cathode, 10-anode, 11-microfluidic channel sweat outlet hole, 12-CBV ventilation valve, 13-microfluidic channel first sweat inlet hole, 14-microfluidic channel second sweat inlet hole, 15-sweat collection chamber, 16-screen printed electrode layer connecting line. DETAILED DESCRIPTION

[0048] The above contents of the present invention are further described in detail below in the form of embodiments, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the above contents of the present invention belong to the scope of the present invention.

[0049] The experimental methods used in the following examples are all conventional methods unless otherwise specified, and the reagents, methods and equipment used are all conventional reagents, methods and equipment in the technical field unless otherwise specified.

[0050] The present invention proposes a wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme, including a sweat collection and sensing module, an electrochemical detection module and an iontophoresis module;

[0051] The sweat collection and sensing module includes a microfluidic channel and a screen-printed electrode; the microfluidic channel is used to collect sweat; the screen-printed electrode includes a working electrode for detecting glucose, a counter electrode and a reference electrode, forming a three-electrode system; wherein the working electrode for detecting glucose has a functional layer, and the functional layer is modified by a multi-shell metal organic framework layered encapsulated enzyme for detecting glucose and chitosan for fixing the multi-shell metal organic framework layered encapsulated enzyme;

[0052] The electrochemical detection module is used to obtain electrochemical sensing detection data under a three-electrode system;

[0053] The iontophoresis module is used to output an adjustable constant current source so that iontophoresis stimulates skin sweating, and includes a cathode, an anode, a boost conversion module and a constant current source module; the boost conversion module is used to increase the extraction voltage of iontophoresis, and the constant current source module is used to output a constant current to the cathode and the anode.

[0054] The microfluidic channel includes a sweat accumulation layer, a sweat inlet layer and a microfluidic channel layer, and the screen-printed electrode includes a printed electrode layer;

[0055] The sweat accumulation layer includes a sweat collection hole in the middle and surrounding holes for placing electroosmotic gel;

[0056] The sweat inlet layer is arranged on the sweat accumulation layer, and the sweat inlet layer comprises a sweat inlet hole and a hole for placing the electroosmotic gel;

[0057] The microfluidic channel layer is arranged on the sweat inlet layer, and the microfluidic channel layer comprises a sweat collection chamber, a microfluidic channel sweat inlet hole, a microfluidic channel sweat outlet hole and a hole for placing an electroosmotic gel;

[0058] An electrode interface is arranged on the printed electrode layer, and the electrode interface has holes for placing the electroosmotic gel.

[0059] The screen-printed electrode also includes a working electrode for detecting pH; the electrode interface is equipped with a working electrode for detecting glucose, a working electrode for detecting pH, a reference electrode, a counter electrode, and a cathode and an anode of an iontophoresis module.

[0060] It also includes a Bluetooth Soc control and communication module, which includes a control system and a signal transmission module. The control system is used to control the system operation, and the signal transmission module is used to control the system and the transmission of electrical signals. The signal transmission module includes a Bluetooth function.

[0061] It also includes a power management module, which is used to provide charging and discharging protection for the system and provide a voltage that meets the accuracy requirements for the system circuit operation;

[0062] The power management module includes a lithium battery protection circuit, a lithium battery charging management circuit and a DC / DC power conversion circuit; the lithium battery protection circuit is used for charging overvoltage protection and discharging low voltage protection; the lithium battery charging management circuit is used to output a stable charging current, and when the charging is completed, the charging current is reduced to the charging end threshold; the DC / DC power conversion circuit is used to convert the output voltage of the lithium battery into a stable voltage output that meets the accuracy requirements and provides it to the Bluetooth Soc control and communication module and the electrochemical detection module for use.

[0063] It also includes an APP module on the mobile terminal, which is connected to the Bluetooth Soc control and communication module through the mobile terminal by Bluetooth signals to control system settings and receive system data, convert the detection data into sweat glucose concentration value and pH value, and display the glucose detection concentration value, pH value and change curve in real time;

[0064] The Bluetooth Soc control and communication module includes NRF52832 system module, A / D module and D / A module; the NRF52832 system module processes the collected signals and sends them to the mobile terminal where the APP module is located via Bluetooth; the A / D module is used to collect the voltage signal output by the electrochemical detection module; the D / A module is used to output the voltage to control the constant potential of the three-electrode system.

[0065] The electrode interface is connected to a flexible connecting wire, and the flexible connecting wire is connected to a wiring port of a Bluetooth Soc control and communication module through an FPC soft cable connector.

[0066] The present invention proposes a preparation method of a wearable sweat glucose detection system based on a multi-shell metal organic framework encapsulated enzyme, wherein a sweat collection and sensing module is made through a microfluidic channel and a screen-printed electrode; the sweat collection and sensing module, the electrochemical detection module and the ion electrophoresis module are integrated and installed into a wearable sweat glucose detection system; wherein the sweat collection and sensing module is arranged on one side of the detection system so as to be able to fit the skin, and is connected to the electrochemical detection module and the ion electrophoresis module.

[0067] The functional layer is modified by a multi-shell metal organic framework hierarchically encapsulating the enzyme, and the modification method is as follows:

[0068] Activate and set aside a working electrode for detecting glucose; prepare a multi-shell metal organic framework layered encapsulated enzyme; and modify the working electrode for detecting glucose using the multi-shell metal organic framework layered encapsulated enzyme;

[0069] The preparation method of the sweat collection and sensing module is as follows:

[0070] In the sweat accumulation layer, sweat inlet layer, microfluidic channel layer and printed electrode layer, holes for placing electroosmotic gel are respectively formed by laser patterning; the sweat accumulation layer forms sweat collection holes by laser patterning; the sweat inlet layer forms sweat inlet holes by laser patterning; the microfluidic channel layer forms microfluidic channel sweat inlet holes, microfluidic channel sweat outlet holes, CBV ventilation valves and sweat collection chambers by laser patterning; the printed electrode layer is obtained by screen printing; the sweat accumulation layer, sweat inlet layer, microfluidic channel layer and printed electrode layer are assembled to obtain a sweat collection and sensing module.

[0071] The present invention provides a multi-shell metal organic framework layered encapsulated enzyme, which has good stability and a wide detection range. After a continuous 14-day current value detection test (such as Figure 8 ) can well prove its stability; the method for preparing the multi-shell metal organic framework layered encapsulated enzyme is;

[0072] (1) Mix 2-methylimidazole and CTAB and add GO x, Zn(NO3)2·6H2O, and the mixed reaction yielded GOX@ZIF-8;

[0073] Preferably, 2-methylimidazole, CTAB, GO x , the reaction molar ratio of Zn(NO3)2·6H2O is 100-200:0.06-0.08:0.001-0.002:1.7-1.8;

[0074] (2) GOX@ZIF-8 was mixed with 2-methylimidazole and CTAB, and HRP and Zn(NO3)2·6H2O were added to obtain the multi-shell metal organic framework hierarchical encapsulated enzyme GOx@ZIF-8@HRP@ZIF-8;

[0075] Preferably, the reaction molar ratio of GOX@ZIF-8 to 2-methylimidazole, CTAB, HRP, and Zn(NO3)2·6H2O is 100-200:1300-1500:0.8-1.0:0.7-0.8:0.2-0.3;

[0076] The method of the present invention using a multi-shell metal organic framework to layered encapsulate enzymes to modify the working electrode for detecting glucose is as follows:

[0077] The enzyme is encapsulated in a multi-shell metal organic framework in a chitosan solution and dispersed evenly by ultrasonication to obtain a mixed solution, and the mixed solution is drop-coated on the surface of a working electrode for detecting glucose and allowed to stand for 10-20 hours;

[0078] The proportion of the multi-shell metal-organic framework layered encapsulated enzyme dispersed in the chitosan solution can be obtained through experiments to achieve the effect of fixed modification.

[0079] Preferably, the chitosan solution has a pH of 7.4 and a mass concentration of 0.05-5%.

[0080] The present invention is further described in detail below in conjunction with specific embodiments:

[0081] Example 1

[0082] The present embodiment provides a multi-shell metal organic framework encapsulated enzyme glucose sensor, comprising a flexible PET substrate and an electrode system configured on the flexible substrate; the electrode system comprises a working electrode for detecting glucose, a counter electrode and a reference electrode; the counter electrode and the working electrode for detecting glucose are formed by printing conductive carbon paste on the flexible PET substrate, and the reference electrode is formed by printing conductive silver paste on the flexible PET substrate.

[0083] A functional layer is modified on a working electrode for detecting glucose. The functional layer is modified by a multi-shell metal organic framework hierarchical encapsulated enzyme for detecting glucose and chitosan for fixing the multi-shell metal organic framework hierarchical encapsulated enzyme.

[0084] The specific modification method of the working electrode is as follows:

[0085] Step 1. Electrode activation: Soak the electrode in 0.05 mol / mL sulfuric acid solution for 2 hours, then use sulfuric acid solution as the electrolyte to scan 20 cycles by cyclic voltammetry. After the peak value of the CV graph is basically stable, take it out and rinse it with pure water, dry it at room temperature, and store it at 4°C.

[0086] Step 2: Stir 1.75 mL of 2-methylimidazole (790 mM) and CTAB (0.55 mM) aqueous solution at 500 r / min for 5 min, add 600 μL of 5 mg / m glucose oxidase (GOx) solution and continue stirring at the same speed for 1 min; then add 0.25 mL of Zn(NO3)2·6H2O aqueous solution, and continue stirring the mixture at 500 r / min for 5 min; after stirring, let the mixture stand at room temperature for 3 h; collect the synthesized GOX@ZIF-8 solid by centrifugation at 6000 rpm / min for 10 min, wash it once with water, and after washing, centrifuge the formed particles again at 6000 rpm / min for 10 min, remove the upper layer of liquid with a pipette, and disperse them in 1 mL of water.

[0087] Step 3, take 0.2mL of the above-synthesized GOx@ZIF-8 and add it to 1.75mL of 2-methylimidazole (790mM) and CTAB (0.55mM) aqueous solution, and stir at 500r / min for 5min; then add 600μL of HRP solution (5mg / mL) and continue to stir at the same speed for 1min; then add 0.25mL of Zn(NO3)2·6H2O aqueous solution, continue to stir the mixture at 500r / min for 5min and let it stand at room temperature for 1h; collect the synthesized GOx@ZIF-8@HRP@ZIF-8 solid by centrifugation at 6000rpm / min for 10min, wash it once with water, and after washing, centrifuge the formed particles again at 6000rpm / min for 10min, remove the upper liquid with a pipette, and store it at 4℃ for use to obtain a multi-shell metal-organic framework layered encapsulated enzyme.

[0088] Step 4, disperse the multi-shell metal organic framework encapsulated enzyme into a chitosan solution with a mass concentration of 0.1% at pH = 5 and disperse it evenly by ultrasonic dispersion, then drop-coat the obtained mixed solution on the surface of the electrode prepared in step 3, and let it stand for 12 hours to allow the multi-shell metal organic framework encapsulated enzyme to deposit on the electrode surface, thereby obtaining a modified working electrode; the prepared electrode is stored at 4°C.

[0089] Figure 6The cyclic voltammetry curve of the glucose sensor prepared in Example 1 in the glucose concentration range of 0.2mM-1mM; from bottom to top, they are 0.2, 0.4, 0.6, 0.8, and 1.0mM glucose concentrations. It can be seen that the reduction current increases with the increase of glucose concentration, and it can be obtained Figure 7 linear relationship.

[0090] Figure 7 The glucose sensor prepared in Example 1 has a linear relationship between the reduction peak and the glucose concentration in the glucose concentration range of 0.2mM-1mM. According to y=-3.102x-1.678, R2=0.994, it can be seen that the sensor has a good linear relationship in the range of 0.2mM-1mM.

[0091] Figure 8 This is a graph showing the change in peak current of the same electrode when testing a 20 μM glucose solution for 14 consecutive days. It can be seen that the electrode still has strong stability after 14 days of continuous use.

[0092] Example 2

[0093] like Figure 1 As shown, this embodiment provides a wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme, including a sweat collection and sensing module, a Bluetooth Soc control and communication module, an electrochemical detection module, an iontophoresis module, a power management module, and an APP module.

[0094] like Figure 1 and Figure 2 As shown, when the wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme is working, first, a 3.3V voltage is generated by the power management module to power the Bluetooth Soc control and communication module, and the ion electrophoresis module is controlled by the GPIO port to start working. After waiting for the ion electrophoresis to be completed, the mobile terminal APP module sends a signal control instruction through Bluetooth, and the Bluetooth Soc control and communication module controls the D / A module to output two constant voltages so that the potential difference between the working electrode 5 for detecting glucose, the working electrode 6 for detecting pH and the reference electrode 7 remains unchanged; then, the mobile phone APP sends a detection instruction through Bluetooth, the electrochemical detection module starts working, and sends the detected glucose and pH signals to the mobile terminal APP, which are converted into the concentration value and pH value of sweat glucose after data processing by the App module, and displayed in real time.

[0095] The sweat collection and sensing module is composed of microfluidic channels and screen-printed electrodes, such as Figure 3As shown, the microfluidic channel is viewed from the bottom layer, and from bottom to top, it is a sweat accumulation layer 4, a sweat inlet layer 3, a microfluidic channel layer 2 and a printed electrode layer 1. The size of the sweat accumulation layer 4, the sweat inlet layer 3, and the microfluidic channel layer 2 is 20 mm × 20 mm, and the size of the printed electrode layer 1 is 20 mm × 35 mm. Figure 4 As shown, the screen-printed electrode is composed of the working electrode 5 for detecting glucose, the working electrode 6 for detecting pH, the reference electrode 7, the counter electrode 8, and the cathode 9 and the anode 10 for iontophoresis prepared in Example 1. The screen-printed electrode is made by screen printing technology. Conductive silver paste and conductive carbon oil are used on the PET film according to the customized Figure 4 Printed.

[0096] The preparation method of the sweat collection and sensing module is specifically as follows:

[0097] A 50W CO2 laser cutting machine was used to make the microfluidic channel; in the sweat accumulation layer 4, the sweat inlet layer 3, the microfluidic channel layer 2 and the printed electrode layer 1, the holes for the cathode 9 and the anode 10 for placing the iontophoresis gel were patterned and the positions corresponded so that the hydrogel was in contact with the skin; the sweat accumulation layer 4 (the double-sided adhesive layer in contact with the skin) was patterned with sweat collection holes (130 microns 3M 468MP, laser parameters: power 15%, speed 12%); the two sweat inlet holes (100 microns thick PET, laser parameters: power 10%, speed 12%) of the sweat inlet layer 3 were patterned; as shown in FIG. Figure 5 As shown, for the microfluidic channel layer 2, a PET film with a thickness of 100 μm is sandwiched between double-sided medical adhesives (130 μm 3M 468MP), which is cut into a first sweat inlet hole 13 of the microfluidic channel, a second sweat inlet hole 14 of the microfluidic channel, a CBV ventilation valve 12, a sweat outlet hole 11 of the microfluidic channel, and a sweat collection chamber 15 (laser parameters: power 15%, speed 15%), the first sweat inlet hole 13 of the microfluidic channel, the second sweat inlet hole 14 of the microfluidic channel correspond to the positions of the two sweat inlet holes of the sweat inlet layer 3; the thickness of the microfluidic channel layer 2 is about 360 μm, the sweat collection chamber 15 is circular (radius 5 mm), and the total volume of the reservoir is about 28.27 μL; then the printed electrode layer 1 is screen-printed on the PET film, and finally the sweat accumulation layer 4, the sweat inlet layer 3, the microfluidic channel layer 2 and the printed electrode layer 1 are assembled to obtain the sweat collection and sensing module of the present invention.

[0098] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any technician familiar with the profession, without departing from the scope of the technical solution of the present invention, according to the technical essence of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the present invention.

Claims

1. A wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme, characterized by: It includes a sweat collection and sensing module, an electrochemical detection module and an iontophoresis module; The sweat collection and sensing module comprises a microfluidic channel and a screen-printed electrode; the microfluidic channel is used to collect sweat; the screen-printed electrode comprises a working electrode for detecting glucose, a counter electrode and a reference electrode, forming a three-electrode system; wherein the working electrode for detecting glucose has a functional layer, and the functional layer is modified by a multi-shell metal organic framework layered encapsulated enzyme for detecting glucose and chitosan for fixing the multi-shell metal organic framework layered encapsulated enzyme; The electrochemical detection module is used to obtain electrochemical sensing detection data under a three-electrode system; The iontophoresis module is used to output an adjustable constant current source so that iontophoresis stimulates the skin to sweat, and includes a cathode, an anode, a boost conversion module and a constant current source module; the boost conversion module is used to increase the extraction voltage of iontophoresis, and the constant current source module is used to output a constant current to the cathode and the anode.

2. The wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme according to claim 1 is characterized by: The microfluidic channel comprises a sweat accumulation layer, a sweat inlet layer and a microfluidic channel layer, and the screen-printed electrode comprises a printed electrode layer; The sweat accumulation layer comprises a sweat collection hole in the middle and surrounding holes for placing electroosmotic gel; The sweat inlet layer is arranged on the sweat accumulation layer, and the sweat inlet layer comprises a sweat inlet hole and a hole for placing the electroosmotic gel; The microfluidic channel layer is arranged on the sweat inlet layer, and the microfluidic channel layer includes a sweat collection chamber, a microfluidic channel sweat inlet hole, a microfluidic channel sweat outlet hole and a hole for placing an electroosmotic gel; The printed electrode layer is provided with an electrode interface, and the electrode interface has holes for placing the electroosmotic gel.

3. The wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme according to claim 2 is characterized by: The screen-printed electrode also includes a working electrode for detecting pH; the electrode interface is equipped with a working electrode for detecting glucose, a working electrode for detecting pH, a reference electrode, a counter electrode, and a cathode and an anode of an iontophoresis module.

4. The wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme according to claim 2 is characterized by: It also includes a Bluetooth Soc control and communication module, which includes a control system and a signal transmission module. The control system is used to control the system operation, and the signal transmission module is used to control the system and the transmission of electrical signals. The signal transmission module includes a Bluetooth function.

5. The wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme according to claim 4 is characterized by: It also includes a power management module, which is used to provide charge and discharge protection for the system and provide a voltage that meets the accuracy requirements for the system circuit operation; The power management module includes a lithium battery protection circuit, a lithium battery charging management circuit and a DC / DC power conversion circuit; the lithium battery protection circuit is used for charging overvoltage protection and discharging low voltage protection; the lithium battery charging management circuit is used to output a stable charging current, and when charging is completed, the charging current is reduced to the charging end threshold; the DC / DC power conversion circuit is used to convert the voltage output by the lithium battery into a stable voltage output that meets the accuracy requirements and provides it to the Bluetooth Soc control and communication module and the electrochemical detection module for use.

6. The wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme according to claim 4 is characterized by: It also includes an APP module on the mobile terminal, which is connected to the Bluetooth Soc control and communication module through the mobile terminal by a Bluetooth signal to control the system settings and receive system data, convert the detection data into sweat glucose concentration value and pH value, and display the glucose detection concentration value, pH value and change curve in real time; The Bluetooth Soc control and communication module includes an NRF52832 system module, an A / D module and a D / A module; the NRF52832 system module processes the collected signals and sends them to the mobile terminal where the APP module is located via Bluetooth; the A / D module is used to collect the voltage signal output by the electrochemical detection module; the D / A module is used to output the voltage to control the constant potential of the three-electrode system.

7. The wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme according to claim 4 is characterized by: The electrode interface is connected to a flexible connecting wire, and the flexible connecting wire is connected to the wiring port of the Bluetooth Soc control and communication module through an FPC soft cable connector.

8. The method for preparing a wearable sweat glucose detection system based on a multi-shell metal organic framework encapsulated enzyme according to any one of claims 1 to 7, characterized in that: A sweat collection and sensing module is made by microfluidic channels and screen-printed electrodes; the sweat collection and sensing module, the electrochemical detection module and the ion electrophoresis module are integrated and installed as a wearable sweat glucose detection system; wherein the sweat collection and sensing module is arranged on one side of the detection system so as to be able to fit the skin, and is connected to the electrochemical detection module and the ion electrophoresis module.

9. The method for preparing a wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme according to claim 8, characterized in that: The functional layer is modified by layered encapsulation of enzymes by a multi-shell metal organic framework, and the modification method is: Activate the working electrode for glucose detection and set it aside; prepare a multi-shell metal organic framework for hierarchical encapsulation of enzymes; A multi-shell metal-organic framework was used to hierarchically encapsulate enzymes to modify the working electrode for glucose detection; The preparation method of the sweat collection and sensing module is as follows: In the sweat accumulation layer, sweat inlet layer, microfluidic channel layer and printed electrode layer, holes for placing electroosmotic gel are respectively formed by laser patterning; the sweat accumulation layer forms sweat collection holes by laser patterning; the sweat inlet layer forms sweat inlet holes by laser patterning; the microfluidic channel layer forms microfluidic channel sweat inlet holes, microfluidic channel sweat outlet holes, CBV ventilation valves and sweat collection chambers by laser patterning; the printed electrode layer is obtained by screen printing; the sweat accumulation layer, sweat inlet layer, microfluidic channel layer and printed electrode layer are assembled to obtain a sweat collection and sensing module.

10. The method for preparing a wearable sweat glucose detection system based on multi-shell metal organic framework encapsulated enzyme according to claim 9, characterized in that: The method for preparing a multi-shell metal organic framework hierarchical encapsulation enzyme is: Mix 2-methylimidazole and CTAB and add GO x , Zn(NO3)2·6H2O, and the mixed reaction yielded GOX@ZIF-8; GOX@ZIF-8 was mixed with 2-methylimidazole and CTAB, and HRP and Zn(NO3)2·6H2O were added to obtain the multi-shell metal organic framework hierarchical encapsulated enzyme GOx@ZIF-8@HRP@ZIF-8. The method of using a multi-shell metal organic framework to hierarchically encapsulate enzymes to modify the working electrode for detecting glucose is as follows: The multi-shell metal organic framework layered encapsulated enzyme is evenly dispersed in the chitosan solution to obtain a mixed solution, and the mixed solution is drop-coated on the surface of the working electrode for detecting glucose and allowed to stand for 10-20 hours.

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