Continuous glucose sensing device based on microneedle array and preparation method

Abstract

The invention relates to the technical field of sensors, and discloses a continuous glucose sensing device based on a microneedle array and a preparation method, the device comprises a base and a metal microneedle array, the base is a printed circuit board, conductive contacts are attached to the back surface of the base, and a metal through hole array is arranged on the base; the metal microneedle array is fixed in the metal through hole array from the front surface of the base; the adjacent metal microneedles are electrically connected, and the metal microneedles and the conductive contacts are electrically connected. The metal microneedle array is divided into a glucose sensing area and a differential sensing area, metal microneedles in the glucose sensing area and the differential sensing area are modified to comprise counter electrodes, working electrodes and reference electrodes, the working electrodes of the glucose sensing area are modified with glucose oxidase layers, and the reference electrodes of the glucose sensing area are modified with reference electrodes. And no glucose oxidase layer is arranged on the working electrode in the differential sensing area. By introducing the differential sensing electrode, common-mode interference signals caused by other electrochemical active substances can be effectively removed, and an accurate detection result is obtained.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a continuous glucose sensing device based on a microneedle array and a preparation method thereof. Background Art

[0002] Compared with the previous method of measuring blood glucose concentration by collecting fingertip blood, many current studies focus on non-invasive monitoring, such as detecting blood glucose levels on the skin surface by electrochemical or optical methods. However, both methods face major challenges in practical application, and the changes in glucose concentration observed in sweat are significantly delayed compared to blood. To solve the above problems, a direct analysis method of subcutaneous interstitial fluid has been developed. Among them, microneedle technology (MN) technology uses micron-sized needles that can penetrate the skin and obtain interstitial fluid in a painless and non-invasive way, and glucose can be detected without a long needle.

[0003] At present, there are many problems with the existing microneedle technology. First, it is difficult to integrate high-density sensors with different functions on a single microneedle array, that is, most of the existing blood glucose sensors are single-channel sensors, which are easily affected by interferences, resulting in reduced detection accuracy. In addition, in the field of continuous glucose monitoring, the preparation of microneedle arrays usually adopts methods such as 3D printing, photolithography or mold forming, and then the conductive area of ​​the microneedle array electrodes is divided by mask plate combined with metal plating technology, and then the sensing functionalization is performed. This process is complex, costly, and the microneedle array sensor is easy to break. In addition, the preparation process of sensors based on microneedle arrays is relatively complex, and it is difficult to easily integrate with the signal acquisition system.

[0004] Application Contents In view of the defects of the prior art, the purpose of this application is to provide a continuous glucose sensing device based on a microneedle array and a preparation method, which mainly solves the problem that the existing glucose sensors are single-channel sensors, which are easily interfered and have low detection accuracy.

[0005] To achieve the above-mentioned purpose, the present application provides a continuous glucose sensing device based on a microneedle array, comprising: a base and a metal microneedle array, wherein the base is a printed circuit board, a conductive contact is attached to the back of the base, and a metal through-hole array is provided on the base; the metal microneedle array is fixed in the metal through-hole array from the front of the base; adjacent metal microneedles and metal microneedles and conductive contacts are electrically connected; the metal microneedle array is divided into a glucose sensing area and a differential sensing area, and the metal microneedles in the glucose sensing area and the differential sensing area are modified by a functional modification layer to include a counter electrode, a working electrode and a reference electrode, wherein the working electrode in the glucose sensing area is modified with a glucose oxidase layer, and the working electrode in the differential sensing area is not provided with a glucose oxidase layer.

[0006] Compared with the prior art, the above technical solution conceived by the present application can effectively remove the common-mode interference signal caused by other electrochemically active substances and obtain more accurate glucose detection results due to the introduction of differential sensing electrodes in the glucose sensor device.

[0007] Furthermore, the functional modification layer on the working electrode of the glucose sensing area includes, from the inside to the outside, a conductive layer, an electron transfer mediator layer, a glucose oxidase layer, a cross-linking layer and a semi-permeable membrane layer.

[0008] Furthermore, the functional modification layer on the working electrode in the differential sensing area includes, from the inside to the outside, a conductive layer, an electron transfer mediator layer, a cross-linking layer and a semi-permeable membrane layer.

[0009] Furthermore, the counter electrode, the working electrode and the reference electrode each include at least one metal microneedle.

[0010] Furthermore, in the glucose sensing region and the differential sensing region, the ratio of the number of metal microneedles modified as the counter electrode, the working electrode and the reference electrode is 10:5:5.

[0011] Furthermore, the length of the metal microneedles in the metal microneedle array is 1 μm-5 mm, and the diameter thereof is in the range of 50 μm-1 mm.

[0012] Furthermore, the continuous glucose sensor device also includes a signal acquisition device, and the signal acquisition device is electrically connected to the conductive contact.

[0013] According to another aspect of the present application, a method for preparing the continuous glucose sensor device as described above is also disclosed, the method comprising: S1 divides the prefabricated metal microneedle array into a glucose sensing area and a differential sensing area; S2: modifying the metal microneedles in the glucose sensing area and the differential sensing area with functional modification layers respectively to obtain the same counter electrode and reference electrode, and different working electrodes, wherein the working electrode in the glucose sensing area has a glucose oxidase layer, and the working electrode in the differential sensing area does not have a glucose oxidase layer; S3 installs the modified microneedle array into the metal through-hole array of the prefabricated base to obtain a continuous glucose sensing device.

[0014] In this application, the microneedle array is prefabricated with commercial stainless steel acupuncture needles with excellent conductivity, and the base is prepared into a structure with metal through-holes on the surface through the printed circuit board (PCB) process. The microneedles are embedded in these through-holes, and the electrical connection between the microneedles is achieved through the electrical connection design inside the PCB. This design method allows each microneedle in the microneedle array of the glucose sensing area and the differential sensing area to be used as an independent electrode (counter electrode, reference electrode or working electrode), thereby achieving the effect of integrating multiple sensors on a smaller microneedle array.

[0015] Furthermore, the step of modifying the metal microneedles in the glucose sensing area with a functional modification layer in step S2 includes: S201 immersing the metal microneedle in the glucose sensing area into a 10 mM HAuCl4 solution for a preset reaction time to obtain a first conductive microneedle with a gold nanoparticle layer attached thereto; S202: Divide the first conductive microneedle into three parts, dip-coat the surface of the first conductive microneedle with Ag / AgCl slurry and then dip-coat the electrode protection layer to obtain the reference electrode of the glucose sensing area; sequentially modify the surface of the second first conductive microneedle with an electron transfer mediator layer, a glucose oxidase layer, a cross-linking layer and a semipermeable membrane layer to obtain the working electrode of the glucose sensing area; and use the third first conductive microneedle as the counter electrode of the glucose sensing area.

[0016] Furthermore, the step of modifying the metal microneedles in the differential sensing area with a functional modification layer in step S2 includes: S211 immersing the metal microneedle in the differential sensing area into a 10 mM HAuCl4 solution for a preset reaction time to obtain a second conductive microneedle with a gold nanoparticle layer attached thereto; S212: The second conductive microneedle is divided into three parts, and the surface of the first part of the second conductive microneedle is dip-coated with Ag / AgCl slurry and then with an electrode protective layer to obtain a reference electrode of the differential sensing area; an electron transfer mediator layer, a cross-linking layer and a semi-permeable membrane layer are sequentially coated on the surface of the second conductive microneedle to obtain a working electrode of the differential sensing area; and the third part of the second conductive microneedle is used as a counter electrode of the differential sensing area.

[0017] Compared with the prior art, the above technical solution conceived by this application has the following beneficial effects: 1. The glucose sensing device provided in the present application introduces a differential sensing electrode to form two sensors on a microneedle array. The difference between the two sensors can be considered as an absolute glucose signal without any other interference, and the differential operation of the two sensors can be completed before the signal acquisition device collects the signal, which can effectively remove the common-mode interference signal caused by other electrochemically active substances and obtain more accurate glucose detection results.

[0018] 2. The glucose sensing device provided in this application can realize continuous, painless and real-time subcutaneous interstitial fluid (ISF) glucose monitoring in a low-cost manner. When the metal microneedle is inserted into the epidermis, the interstitial fluid (ISF) glucose signal of the monitored object can be continuously collected and transmitted to an external application via wireless or wired transmission for data visualization and analysis, which significantly improves the anti-interference ability and detection accuracy.

[0019] 3. In the preparation method of the glucose sensor device provided in the present application, the microneedle array is pre-made of commercial stainless steel acupuncture needles with excellent conductivity, and the base is prepared into a structure with metal through holes on the surface through a printed circuit board (PCB) process, both of which are low-cost and highly repeatable manufacturing methods. The metal microneedle array is embedded in the corresponding through holes, and the electrical connection between the metal microneedles is achieved through the electrical connection design inside the PCB. This design method allows each microneedle in the microneedle array of the glucose sensing area and the differential sensing area to be used as an independent electrode (counter electrode, reference electrode or working electrode), thereby achieving the effect of integrating multiple sensors on a smaller microneedle array.

[0020] 4. The integrated microneedle array and base in this application ensure the reliability of piercing the object to be detected and the robustness of the glucose sensor device. Compared with the conical needles made by traditional methods, the cylindrical metal microneedles have higher piercing efficiency and smaller piercing force. At the same time, compared with microneedles made of brittle materials such as resin, silicon or SU-8, metal microneedles will not break when affected by external forces, and have higher biosafety. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the structure of the continuous glucose sensing device provided in Example 1 of the present application; Figure 2 This is a schematic diagram of the assembly structure of the base and the metal microneedle array in the continuous glucose sensing device provided in Example 1 of the present application; Figure 3 It is a schematic diagram of the partial structure of the base and the shell assembly equipped with the metal microneedle array provided in Example 1 of the present application; Figure 4It is a schematic diagram of the separate structure of a base equipped with a metal microneedle array and a corresponding shell provided in Example 1 of the present application; Figure 5 This is a schematic diagram of an internal wiring structure equipped with a metal microneedle array and conductive contacts provided in Example 1 of the present application; Figure 6 This is a schematic diagram of the detection effect of the continuous glucose sensing device under different microneedle spacings provided in Example 1 of the present application; Figure 7 This is a schematic diagram of the detection effect of the continuous glucose sensor device provided in Example 1 of the present application; Figure 8 This is a schematic diagram of the process of preparing microneedle electrodes in the continuous glucose sensing device provided in Example 2 of the present application.

[0022] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-base, 11-conductive contact, 12-metal through-hole array, 2-metal microneedle array, 3-signal acquisition device, 4-spring terminal, 5-housing. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of the present application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0025] In addition, references throughout this specification to "one embodiment"; "one embodiment", "an example" or similar language indicate that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present application. Thus, appearances of the phrase "in one embodiment"; "in one embodiment" and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0026] Example 1 This embodiment provides a continuous glucose sensing device based on a microneedle array, such as Figure 1-5As shown, the glucose sensor device includes: a base 1 and a metal microneedle array 2, the base 1 is a printed circuit board, and a conductive contact 11 is attached to the back of the base 1, and a metal through-hole array 12 is provided on the base 1; the metal microneedle array 2 is fixed in the metal through-hole array 12 from the front of the base 1; the adjacent metal microneedles and the metal microneedles and the conductive contacts 11 are electrically connected through the internal wiring of the base 1; the metal microneedle array 2 is divided into a glucose sensing area and a differential sensing area, and the metal microneedles in the glucose sensing area and the differential sensing area are modified by a functional modification layer to include a counter electrode, a working electrode and a reference electrode, wherein the working electrode in the glucose sensing area is modified with a glucose oxidase layer, and the working electrode in the differential sensing area is not provided with a glucose oxidase layer.

[0027] Specifically, the aforementioned metal microneedle array is mainly composed of stainless steel microneedles and a base for fixing the microneedles. The length of a single metal microneedle (hereinafter referred to as microneedle) in the metal microneedle array 2 is 1 μm-5 mm, and its diameter ranges from 50 μm-1 mm.

[0028] In this embodiment, the microneedles used are acupuncture needles with a diameter of 160μm, a needle tip diameter of 10μm, and a length of 7mm, and the microneedles are cut into 3mm lengths. The microneedle base is made of a printed circuit board (PCB) with microholes, and the microneedles can be accurately fixed in the corresponding micro-shaped through holes on the printed circuit board. The electrical connection between the microneedles can be achieved by routing inside the PCB board, which is lower in cost and more efficient than making electrical circuits through a mask.

[0029] In this embodiment, the microneedle array contains 40 microneedles. Acupuncture needles with a diameter of 160 μm are cut into 3 mm lengths and arranged in 5×8 rows on a base with microholes. The base is circular with a diameter of 15 mm and a thickness of 1 mm. Figure 5 As shown, the electrical connection between the microneedles is designed inside the base, where the wires for connecting between the through holes are located on the top layer of the base 1, and the connecting wires between the through holes and the conductive contacts 11 are located on the bottom layer of the base 1. This is achieved through the PCB manufacturing process, which is a cost-effective and highly repeatable manufacturing method. The spacing between adjacent microneedles is 1mm or 1.5mm. Figure 6 As shown in Figure 2, Figure b shows the strain distribution of microneedle arrays with different spacings at the moment of skin penetration. Figure 6 At 0.25 mm (i) and 0.5 mm (ii) as shown in a, there is an obvious gap around the middle needle between the microneedle base and the skin surface, and the actual penetration depth of the microneedle is L p Compared with the actual length L of the microneedle, there is a large change, resulting in low puncture efficiency. As the spacing increases from 0.75mm to 1mm, the difference in skin strain distribution gradually decreases ( Figure 6As shown in Figure c, iii and iv). Figure 6 In Figure iv of Figure c, the difference in insertion efficiency between microneedles is small, so it can be considered that the effect caused by the spacing between microneedles can be ignored at this time, so the microneedle spacing must be at least 1mm. When the microneedle spacing reaches 1.5mm, it can also produce an effect similar to that of 1mm.

[0030] The functional modification layers on the working electrode of the aforementioned glucose sensing area include a conductive layer, an electron transfer mediator layer, a glucose oxidase layer, a cross-linking layer and a semi-permeable membrane layer from the inside to the outside. Specifically, the nano-gold layer is modified on the microneedle as a conductive layer, the Prussian blue layer is modified as an electron transfer mediator layer, the glucose oxidase (Gox) layer is modified as a cross-linking layer, and the Nafion layer (perfluorosulfonic acid polymer layer) is modified as a semi-permeable membrane layer, thereby constructing a glucose sensing electrode.

[0031] In this embodiment, the reference electrode is an Ag / AgCl reference electrode prepared by modifying a commercial Ag / AgCl slurry on a microneedle, and the stability of the reference electrode is tested in a PBS solution, and the voltage drift thereof is 0.752 mV / h.

[0032] The functional modification layers on the working electrode in the differential sensing area include a conductive layer, an electron transfer mediator layer, a cross-linking layer and a semi-permeable membrane layer from the inside to the outside. The reference electrode and the counter electrode are the same as those in the glucose sensing area. The reference electrode is a conductive layer, an Ag / AgCl layer and an electrode protection layer modified layer by layer on the microneedle electrode; the counter electrode is a gold, platinum or titanium layer modified layer by layer on the microneedle electrode.

[0033] The counter electrode, working electrode and reference electrode in the aforementioned glucose sensing area and differential sensing area respectively include at least one metal microneedle, that is, any one microneedle or part of the microneedles can be used alone or together as a counter electrode, working electrode or reference electrode.

[0034] In the glucose sensing area and the differential sensing area of ​​the present embodiment, the number ratio of the metal microneedles modified into the counter electrode, working electrode and reference electrode is 10:5:5. For example, 20 metal microneedles are modified into the counter electrode, working electrode and reference electrode of the glucose sensing area according to the number ratio of 10:5:5, the number of microneedles of the counter electrode is 10, and the number of microneedles of the working electrode and the reference electrode is 5; another 20 metal microneedles are also modified into the counter electrode (CE), working electrode (WE) and reference electrode (RE) of the differential sensing area according to the number ratio of 10:5:5.

[0035] The aforementioned continuous glucose sensor device also includes a signal acquisition device 3, which is electrically connected to the conductive contact 11; specifically, the base 1 equipped with the metal microneedle array and the signal acquisition device 3 can be assembled into one body through a shell 5 that is compatible with the appearance of the base 1, and the electrical connection between the two is achieved through a spring terminal 4; more specifically, the signal acquisition device 3 can also be separately equipped with a fixed shell, which is fixed in the shell 5 of the glucose sensor device to form a complete continuous blood glucose monitoring device.

[0036] The aforementioned signal acquisition device 3 includes an analog circuit for signal acquisition, amplification, and filtering, a power management module, a battery, a wireless charging module, a processor module (MCU), and a wireless communication module. The connection method and information transmission method of the above modules are conventional technical means for those skilled in the art and will not be repeated here.

[0037] like Figure 3 As shown, the shell wall at the position where the microneedle array is assembled can be designed to have different wall thicknesses. h , so that the length of the microneedle exposed outside the shell l With the shell thickness h The depth of penetration into the skin can be adjusted by adjusting the depth of penetration into the skin.

[0038] In this embodiment, an external application can also be connected to communicate with the continuous glucose monitoring device of the present application through wireless communication technologies such as Bluetooth. For example, a smartphone application can send instructions to the signal acquisition device 3 so that the continuous glucose monitoring device works under specific conditions. At the same time, it can also receive the glucose signal sent by the signal acquisition device 3, and then convert it into a corresponding glucose concentration and display it on a customized smartphone application. The smartphone application can also communicate with the hardware circuit of the continuous glucose monitoring device through Bluetooth, and can set the working mode and working conditions of the continuous glucose monitoring device. At the same time, it can receive the voltage signal sent by the hardware circuit and convert the voltage signal into a corresponding blood glucose concentration. At the same time, the smartphone application can also record blood glucose historical data in real time, and users can view, save and share this data.

[0039] The microneedle array-based glucose sensor provided in the above embodiment has a low manufacturing cost, can significantly improve the integration density of the sensor, and effectively reduce the size of the microneedle array. At the same time, the present application designs the microneedle array electrode by contact connection, which is convenient for efficient integration with the signal acquisition device.

[0040] The continuous glucose sensing device based on the microneedle array provided in this embodiment was tested on healthy subjects. Figure 7As shown in a, the continuous glucose sensor device is pressed to puncture the epidermis and fixed with double-sided tape. The test starts immediately, and the continuous glucose sensor device collects current signals every 0.5s and sends them to the mobile device. The mobile terminal processes these current signals, calculates the average value of the current signal within this time period every 3 minutes, and converts it into glucose concentration. The real-time current signal and glucose concentration are displayed on the mobile terminal, and the historical data of glucose concentration can be saved and shared.

[0041] like Figure 7 As shown in Figure b, the test scenario is divided into performing a single event on the test subjects (one male and one female) for the sensor and performing multiple events on a single test subject. The single event requires the test subject to eat the same food and then collect its blood sugar response. Figure 7 As shown in Figure d, the multi-event activity requires the subject to eat dessert after a full meal, and collect continuous blood sugar fluctuations to demonstrate the response of the continuous glucose sensor device to different activities. Figure 7 As shown in Figure ii in Figure d, after eating, the ISF glucose level of each subject monitored every 3 minutes rose rapidly from the background value (5mM~5.5mM when fasting), reached a peak within 30-60 minutes, and then gradually decreased to the original basal value. For all subjects, calibration was performed by measuring fingertip blood glucose values ​​(once every 20 minutes). The Clarke grid was used to perform error analysis on the two data sets (see Figure 2). Figure 7 As shown in c), all data points are within the clinically acceptable error zone A (indicating that the error has little impact on the patient's clinical decision), highlighting the powerful performance of the continuous glucose sensing device in accurately and continuously tracking dynamic glucose fluctuations in the body. And personalized responses were observed in terms of glucose peak intensity (8.5mM~9.8mM), glucose uptake rate (50min-60min) and glycolysis rate (85min~170min). The area under the glucose curve (AUC) has been shown to be a more sensitive predictor than HbA1c and fasting blood glucose levels, and can be used to detect diabetes and impaired glucose tolerance, as well as to identify people at increased risk of diabetes. The AUCs of the two subjects were 14.4 (3.5) mMh and 21.5 (6.2) mMh, respectively. The AUC data of the continuous glucose sensing device showed that the female subject had a higher risk of diabetes than the male subject. In summary, the microneedle sensor showed an accurate physical response in detecting glucose, indicating the detection accuracy of the continuous glucose sensing device provided in the above embodiment.

[0042] Example 2 This embodiment provides a method for preparing the continuous glucose sensor device as described in Example 1. The preparation method process is as follows: Figure 8 As shown, the steps of the preparation method include: S1 divides the prefabricated metal microneedle array 2 into a glucose sensing area and a differential sensing area; S2: The metal microneedles in the glucose sensing area and the differential sensing area are modified with functional modification layers to obtain the same counter electrode and reference electrode, and different working electrodes, wherein the working electrode in the glucose sensing area has a glucose oxidase layer, and the working electrode in the differential sensing area does not have a glucose oxidase layer; The steps of modifying the metal microneedle in the glucose sensing area with a functional modification layer include: S201 immerses the metal microneedle in the glucose sensing area into a 10 mM HAuCl4 solution for a preset reaction time to obtain a first conductive microneedle with a gold nanoparticle layer attached thereto; S202 divides the first conductive microneedle into three parts, and dips the surface of the first conductive microneedle into Ag / AgCl slurry and then dips the electrode protective layer into an electrode to obtain a reference electrode of the glucose sensing area; sequentially modifies the surface of the second first conductive microneedle into an electron transfer mediator layer, a glucose oxidase layer, a cross-linking layer and a semipermeable membrane layer to obtain a working electrode of the glucose sensing area; and uses the third first conductive microneedle as a counter electrode of the glucose sensing area.

[0043] The steps of modifying the metal microneedle in the differential sensing area with a functional modification layer include: S211 immersing the metal microneedle in the differential sensing area into a 10 mM HAuCl4 solution for a preset reaction time to obtain a second conductive microneedle with a gold nanoparticle layer (i.e., a metal layer) attached thereto; S212 The second conductive microneedle is divided into three parts, and the surface of the first second conductive microneedle is dip-coated with Ag / AgCl slurry and then with an electrode protective layer to obtain a reference electrode of the differential sensing area; an electron transfer mediator layer, a cross-linking layer and a semi-permeable membrane layer are sequentially coated on the surface of the second conductive microneedle to obtain a working electrode of the differential sensing area; the third second conductive microneedle is used as a counter electrode of the differential sensing area.

[0044] More specifically, a layer of Prussian blue was electrodeposited on the surface of the working electrode as an electron transport medium in a fresh solution containing 2.5 mM FeCl3, 100 mM KCl, 2.5 mM K3Fe(CN)6 and 100 mM HCl at a constant potential (0.4 V vs. Ag / AgCl) for 200 seconds. Chitosan was dissolved in 2% acetic acid and stirred at 80 °C for 1 hour to prepare a 1 wt% chitosan solution. GOx enzyme solution was prepared in chitosan solution at a volume ratio of 1:2, and the concentration range of GOx enzyme solution was 5 mg / mL to 30 mg / mL. The microneedle array deposited with Prussian blue was immersed in GOx enzyme solution for 5 minutes and then dried at 4°C. The microneedle array was then immersed in polyethylene glycol diglycidyl ether PEGDE (1%) solution for 1 minute for crosslinking. Finally, the microneedle array was immersed in 0.05% Nafion (perfluorosulfonic acid polymer) solution for 30 seconds and then dried at 4°C to obtain a microneedle array sensor. The modification process of the metal microneedles in the differential sensing area is the same as that of the glucose sensing area, except that the glucose oxidase does not need to be modified.

[0045] S3 installs the modified microneedle array into the metal through-hole array 12 of the prefabricated base 1 to obtain a continuous glucose sensor device. Specifically, the metal microneedle array is installed into the microneedle through-holes of the base 1 prepared by the printed circuit board process, and then the assembled continuous glucose sensor device is connected to the signal acquisition device 3 through the spring terminal 4 to collect the sensing signal, and then assembled into one through the housing 5 adapted to the appearance of the base 1, and the spring terminal 4 is connected between the two to achieve electrical connection; the signal acquisition device 3 is also separately equipped with a fixed housing, and the fixed housing is fixed in the housing 5 of the glucose sensor device to form a complete continuous blood glucose monitoring device.

[0046] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A continuous glucose sensing device based on a microneedle array, characterized in that: include: A base (1) and a metal microneedle array (2), wherein the base (1) is a printed circuit board, a conductive contact (11) is attached to the back of the base (1), and a metal through hole array (12) is provided on the base (1); the metal microneedle array (2) is fixed in the metal through hole array (12) from the front of the base (1); adjacent metal microneedles and the metal microneedles and the conductive contact (11) are electrically connected; the metal microneedle array (2) is divided into a glucose sensing area and a differential sensing area, and the metal microneedles in the glucose sensing area and the differential sensing area are modified with a functional modification layer to include a counter electrode, a working electrode and a reference electrode, wherein the working electrode in the glucose sensing area is modified with a glucose oxidase layer, and the working electrode in the differential sensing area is free of a glucose oxidase layer.

2. A continuous glucose sensing device based on a microneedle array as claimed in claim 1, characterized in that: The functional modification layer on the working electrode of the glucose sensing area comprises, from inside to outside, a conductive layer, an electron transfer mediator layer, a glucose oxidase layer, a cross-linking layer and a semi-permeable membrane layer.

3. A continuous glucose sensing device based on a microneedle array as claimed in claim 1, characterized in that: The functional modification layer on the working electrode in the differential sensing area includes, from inside to outside, a conductive layer, an electron transfer mediator layer, a cross-linking layer and a semi-permeable membrane layer.

4. A continuous glucose sensing device based on a microneedle array as claimed in claim 1, characterized in that: The counter electrode, the working electrode and the reference electrode each include at least one metal microneedle.

5. A continuous glucose sensing device based on a microneedle array as claimed in claim 1, characterized in that: In the glucose sensing area and the differential sensing area, the ratio of the number of metal microneedles modified as the counter electrode, the working electrode and the reference electrode is 10:5:

5.

6. A continuous glucose sensing device based on a microneedle array as claimed in claim 1, characterized in that: The length of the metal microneedles in the metal microneedle array (2) is 1 μm-5 mm, and the diameter thereof is in the range of 50 μm-1 mm.

7. A continuous glucose sensing device based on a microneedle array as claimed in claim 1, characterized in that: The continuous glucose sensor device further comprises a signal acquisition device (3), wherein the signal acquisition device (3) is electrically connected to the conductive contact (11).

8. A method for preparing a continuous glucose sensor device according to any one of claims 1 to 7, characterized in that: The preparation method comprises: S1 divides the prefabricated metal microneedle array (2) into a glucose sensing area and a differential sensing area; S2: modifying the metal microneedles in the glucose sensing area and the differential sensing area with functional modification layers respectively to obtain the same counter electrode and reference electrode, and different working electrodes, wherein the working electrode in the glucose sensing area has a glucose oxidase layer, and the working electrode in the differential sensing area does not have a glucose oxidase layer; S3 installs the modified microneedle array into the metal through-hole array (12) of the prefabricated base (1) to obtain a continuous glucose sensing device.

9. The preparation method according to claim 8, characterized in that: The step of modifying the metal microneedles in the glucose sensing area with a functional modification layer in step S2 includes: S201 immersing the metal microneedle in the glucose sensing area into a 10 mM HAuCl4 solution for a preset reaction time to obtain a first conductive microneedle with a gold nanoparticle layer attached thereto; S202: Divide the first conductive microneedle into three parts, dip-coat the surface of the first conductive microneedle with Ag / AgCl slurry and then dip-coat the electrode protection layer to obtain the reference electrode of the glucose sensing area; sequentially modify the surface of the second first conductive microneedle with an electron transfer mediator layer, a glucose oxidase layer, a cross-linking layer and a semipermeable membrane layer to obtain the working electrode of the glucose sensing area; and use the third first conductive microneedle as the counter electrode of the glucose sensing area.

10. The preparation method according to claim 8, characterized in that: The step of modifying the metal microneedles in the differential sensing area with a functional modification layer in step S2 includes: S211 immersing the metal microneedle in the differential sensing area into a 10 mM HAuCl4 solution for a preset reaction time to obtain a second conductive microneedle with a gold nanoparticle layer attached thereto; S212: The second conductive microneedle is divided into three parts, and the surface of the first part of the second conductive microneedle is dip-coated with Ag / AgCl slurry and then with an electrode protective layer to obtain a reference electrode of the differential sensing area; an electron transfer mediator layer, a cross-linking layer and a semi-permeable membrane layer are sequentially coated on the surface of the second conductive microneedle to obtain a working electrode of the differential sensing area; and the third part of the second conductive microneedle is used as a counter electrode of the differential sensing area.

Images