Closed-loop insulin controlled release system based on microneedle array patch

Abstract

The invention discloses a closed-loop insulin controlled release system based on a microneedle array patch. The method for achieving closed-loop insulin controlled release comprises the steps that the glucose microneedle sensor in the system is used for monitoring the blood glucose concentration, and when the blood glucose concentration is too high, the subcutaneous release state of insulin is regulated and controlled by applying voltage to the insulin controlled release microneedle; wherein each insulin controlled-release microneedle is provided with an independent current path, so that each microneedle is independently addressed, and the release of a single piece or a plurality of pieces of insulin can be regulated and controlled; the insulin gel part of the insulin controlled release microneedle comprises insulin, sodium alginate and metal ions. The invention relates to a closed-loop insulin controlled release system based on a microneedle array patch, and discloses an insulin closed-loop system suitable for diabetics, which can continuously monitor blood sugar and realize active control of insulin release through electric triggering when the blood sugar concentration is relatively high, and has the advantages of convenience, minimally invasive property and controllability.

Description

Technical Field

[0001] The invention belongs to the technical field of medical monitoring and treatment instruments, and in particular relates to a closed-loop insulin controlled-release system based on a microneedle array patch. Background Art

[0002] Diabetes is a chronic disease characterized by high blood sugar, caused by absolute or relative insulin deficiency and utilization disorder. Globally, the incidence and prevalence of diabetes are on the rise.

[0003] At present, the main treatment for patients with type 1 diabetes, gestational diabetes and some type 2 diabetes is to lower blood sugar by injecting insulin through an insulin pump or injection pen before meals and before going to bed. The injection dose is often controlled by experience, and it is impossible to measure whether the blood sugar is stable in the normal range after injection. In addition, repeated injections can easily cause pain, fear and wound infection in patients. Therefore, diabetic patients need less trauma and more precise insulin delivery methods to change the status quo. Microneedle technology is a new drug delivery technology that can pass through the stratum corneum in a painless and minimally invasive way to deliver drugs to the epidermis or upper dermis to exert pharmacological effects. Delivering insulin through microneedle delivery avoids the destruction of insulin by digestive enzymes in oral administration and the skin trauma caused by subcutaneous injection, but how to accurately control the dosage and time of administration has also become a considerable issue of concern. At present, relevant researchers have prepared insulin-releasing microneedle patches that are responsive to blood sugar concentration. When the blood sugar concentration is high, the insulin is released faster; when the blood sugar concentration is low, the insulin is released slowly. Although this patch is simple and can stabilize blood sugar to a certain extent, it cannot determine the remaining insulin in the microneedle patch, when it is used up, and whether it is sufficient, which makes it unable to be used as a tool for long-term continuous insulin delivery.

[0004] Using microneedle technology for the treatment of diabetes, guiding the exact time of insulin release and effectively controlling the release dose of insulin are critical conditions for its promotion and application. Summary of the invention

[0005] In order to solve the problems existing in the background technology, the present invention provides an insulin controllable release microneedle array patch with electrochemical response. Combined with dynamic blood glucose monitoring, the microneedle array patch provides release timing guidance in the case of high blood sugar, thereby achieving long-term and continuous blood sugar management for diabetic patients.

[0006] The technical solution adopted by the present invention is:

[0007] A closed-loop insulin controlled-release system based on a microneedle array patch, comprising a control circuit module, an insulin controlled-release microneedle array patch, and a dynamic blood glucose monitoring microneedle array patch;

[0008] The insulin controlled-release microneedle array patch comprises a first flexible electrode sheet, a first reference electrode and insulin controlled-release microneedle electrodes distributed in an array on the first flexible electrode sheet, wherein the insulin controlled-release microneedle electrodes are based on metal needles, and a gel network formed by metal ion cross-linking sodium alginate is covered on the surface of the metal needles, wherein insulin is wrapped in the gel network; and all electrodes on the first flexible electrode sheet are connected to a control circuit module through an independent first current path, and the control circuit module addresses each insulin controlled-release microneedle electrode individually, and independently controls the reduction voltage applied to the insulin controlled-release microneedle electrode for releasing insulin;

[0009] The dynamic blood glucose monitoring microneedle array patch includes a second flexible electrode sheet, a second reference electrode and dynamic blood glucose monitoring microneedle electrodes distributed in an array form on the second flexible electrode sheet; and all electrodes on the second flexible electrode sheet are connected to a control circuit module through an independent second current path, and the control circuit module addresses each dynamic blood glucose monitoring microneedle electrode separately, independently controls the working voltage applied to the dynamic blood glucose monitoring microneedle electrode, and records the current values ​​on different dynamic blood glucose monitoring microneedle electrodes during the addressing process.

[0010] Preferably, the preparation method of the insulin controlled-release microneedle electrode is: using a metal needle as a working electrode, a silver / silver chloride electrode as a reference electrode, and a platinum electrode as a counter electrode, the three electrodes are immersed in a solution containing sodium alginate, insulin and ferrous sulfate, and insulin gel-covered insulin controlled-release microneedles are obtained by constant current electrolysis.

[0011] Preferably, the preparation method of the insulin controlled-release microneedle electrode is: using a copper-plated metal needle as a working electrode, a silver / silver chloride electrode as a reference electrode, and a platinum electrode as a counter electrode, the three electrodes are immersed in a solution containing sodium alginate and insulin, and insulin gel-covered insulin controlled-release microneedles are obtained by constant current electrolysis.

[0012] Preferably, the reduction voltage applied to the insulin controlled-release microneedle electrode for releasing insulin is -1.0 to -2.0V.

[0013] Preferably, the dynamic blood glucose monitoring microneedle electrode uses a metal needle as a substrate, and the surface of the metal needle is sequentially covered with a platinum layer, an o-phenylenediamine layer, a glucose oxidase layer, a chitosan layer and a polyurethane layer.

[0014] Preferably, the working voltage applied to the dynamic blood glucose monitoring microneedle electrode is +0.2 to +1.0V.

[0015] Preferably, in addition to the first reference electrode, the first flexible electrode sheet of the insulin controlled-release microneedle array patch is also provided with a first pair of electrodes, which are also connected to the control circuit module through an independent first current path, thereby forming a three-electrode system with the insulin controlled-release microneedle electrode.

[0016] Preferably, in addition to the second reference electrode, a second pair of electrodes is provided on the second flexible electrode sheet of the dynamic blood glucose monitoring microneedle array patch. The second pair of electrodes is also connected to the control circuit module through an independent second current path, thereby forming a three-electrode system with the dynamic blood glucose monitoring microneedle electrode.

[0017] Preferably, the control circuit module has an interactive display interface for displaying control parameters and detection parameters, or has a communication module for data interaction with external devices, or has a feedback control module for feedback controlling the release of insulin in an insulin controlled-release microneedle array patch based on the blood glucose concentration detected by a dynamic blood glucose monitoring microneedle array patch.

[0018] Preferably, the metal needle is a gold needle, a platinum needle or a stainless steel needle.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The closed-loop insulin controlled-release system based on the microneedle array patch of the present invention provides a method of regulating insulin release by using an electric field. The metal ions in the insulin controlled-release gel are reduced by regulating the voltage through the circuit board, and the cross-linking degree of the gel is reduced to release insulin subcutaneously, thereby realizing automatic and controllable continuous administration of insulin.

[0021] 2. The closed-loop insulin controlled-release system based on the microneedle array patch of the present invention is equipped with a dynamic blood glucose monitoring module, which is combined with an insulin release module to complete the closed-loop management of blood glucose concentration. It is a closed-loop insulin controlled-release system with miniaturization, convenience, high comfort and low trauma.

[0022] 3. The insulin microneedles used in the closed-loop insulin controlled-release system based on the microneedle array patch of the present invention have metal needles, and the needle body has good mechanical properties, which is convenient for puncturing the skin for subcutaneous administration. The replaceable design of the patch ensures the long-term use of the microneedle array patch. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the overall structure of the closed-loop insulin controlled-release system.

[0024] Figure 2 Schematic diagram of the structure of the insulin controlled-release microneedle patch.

[0025] Figure 3Schematic diagram of the glucose-sensitive microneedles of the dynamic blood glucose monitoring microneedle patch.

[0026] Figure 4 1 is the test result of the current response in the embodiment of the present invention.

[0027] Figure 5 These are the glucose response curves measured by the electrochemical workstation and the flexible printed circuit board in the embodiment of the present invention.

[0028] Figure 6 FIG. 4 is a test result of another current response in an embodiment of the present invention.

[0029] Figure 7 This is the real-time monitoring result of the current signal on rats in the embodiment of the present invention.

[0030] Figure 8 This is a state diagram of the ferric iron insulin gel in the embodiment of the present invention after drying for different lengths of time.

[0031] Fig. 9 This is the fluorescence observation result under a fluorescence microscope in the insulin release experiment in the example of the present invention. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation mode of the present invention is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0033] In the description of the present invention, it is to be understood that when an element is considered to be "connected" to another element, it may be directly connected to the other element or indirectly connected, that is, there are intermediate elements. On the contrary, when an element is said to be "directly" connected to another element, there are no intermediate elements.

[0034] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for the purpose of distinguishing descriptions, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0035] See also Figure 1As shown, in a preferred embodiment of the present invention, a closed-loop insulin controlled release system based on a microneedle array patch is provided, characterized in that it comprises a control circuit module 1, an insulin controlled release microneedle array patch 2, and a dynamic blood glucose monitoring microneedle array patch 3. The control circuit module 1 serves as the main control module of the entire system, and is used to control the respective working states of the insulin controlled release microneedle array patch 2 and the dynamic blood glucose monitoring microneedle array patch 3. The insulin controlled release microneedle array patch 2 can release insulin under the control of the control circuit module 1, and the dynamic blood glucose monitoring microneedle array patch 3 can monitor the blood glucose concentration in real time under the control of the control circuit module 1. The structural forms and working principles of the insulin controlled release microneedle array patch 2 and the dynamic blood glucose monitoring microneedle array patch 3 are described in detail below.

[0036] See also Figure 2 As shown, the insulin controlled-release microneedle array patch 2 includes a first flexible electrode sheet 21, a first reference electrode, and insulin controlled-release microneedle electrodes 22 distributed in an array on the first flexible electrode sheet 21. The insulin controlled-release microneedle electrodes 22 are based on metal needles, and a gel network formed by metal ion cross-linking sodium alginate is covered on the surface of the metal needles, and insulin is wrapped in the gel network. All electrodes on the first flexible electrode sheet 21, including the first reference electrode and the insulin controlled-release microneedle electrodes 22, are each connected to the control circuit module 1 through an independent first current path 23, and the control circuit module 1 addresses each insulin controlled-release microneedle electrode 22 separately, and independently controls the reduction voltage applied to the insulin controlled-release microneedle electrodes 22 for releasing insulin.

[0037] It should be noted that in the above-mentioned insulin controlled-release microneedle array patch 2, the first reference electrode can form a two-electrode system with each insulin controlled-release microneedle electrode 22. However, in other embodiments, another first pair of electrodes (platinum electrodes can be used) in addition to the first reference electrode can be arranged on the first flexible electrode sheet 21, and the first pair of electrodes is also connected to the control circuit module 1 through an independent first current path 23, thereby forming a three-electrode system with the insulin controlled-release microneedle electrode 22. Both the two-electrode system and the three-electrode system can achieve the technical effects of the present invention.

[0038] In an embodiment of the present invention, the preparation method of the above-mentioned insulin controlled-release microneedle electrode 22 can be achieved in two ways. The first implementation method is: using a metal needle as a working electrode, a silver / silver chloride electrode (Ag / AgCl) as a reference electrode, a platinum electrode as a counter electrode, and the three electrodes are immersed in a solution containing sodium alginate, insulin and ferrous sulfate, and the insulin gel-covered insulin controlled-release microneedle is obtained by constant current electrolysis (preferably 30μA constant current electroplating for 60s). The second implementation method is: using a copper-plated metal needle as a working electrode, a silver / silver chloride electrode as a reference electrode, and a platinum electrode as a counter electrode, and the three electrodes are immersed in a solution containing sodium alginate and insulin, and the insulin gel-covered insulin controlled-release microneedle is obtained by constant current electrolysis (preferably 30μA constant current electroplating for 60s). The above two methods can form a gel network wrapped with insulin formed by metal ion cross-linking sodium alginate on the surface of the metal needle, but the metal ions therein are different. In the first implementation method, the metal ions are trivalent iron ions, and in the second method, the metal ions are divalent copper ions. These high-valent ions exchange with the sodium ions in sodium alginate, causing the sodium alginate units to pile up to form a cross-linked network structure, thereby encapsulating insulin molecules. In the present invention, the insulin-releasing gel cross-linked by trivalent iron ions in the first implementation is preferably used.

[0039] In practical applications, the insulin release method in the above-mentioned insulin controlled-release microneedle electrode 22 is as follows: the above-mentioned insulin controlled-release microneedle electrode 22 is used as the working electrode, the silver-silver chloride electrode is used as the reference and counter electrode, and a two-electrode system is formed (a platinum electrode can also be added to form a three-electrode), and a reduction voltage of -1.0 to -2.0V (relative to the voltage between the silver / silver chloride reference electrode) is applied to the working electrode through the control circuit module 1, thereby reducing the trivalent iron ions or divalent copper ions to divalent iron ions or copper elements, and the cross-linking degree of the sodium alginate gel is reduced to release insulin. Since the insulin controlled-release microneedle array patch has multiple insulin microneedles, an independent current path can release a single or multiple insulin microneedles, thereby controlling the release amount and rate. When all insulin microneedles are released, the patch can be removed from the interface with the circuit board and replaced with a new patch to complete the continuous supply of insulin.

[0040] See also Figure 3As shown, the dynamic blood glucose monitoring microneedle array patch 3 includes a second flexible electrode sheet 31, a second reference electrode, and a dynamic blood glucose monitoring microneedle electrode 32 distributed in an array on the second flexible electrode sheet 31. All electrodes on the second flexible electrode sheet 31, including the second reference electrode and the dynamic blood glucose monitoring microneedle electrode 32, are connected to the control circuit module 1 through an independent second current path 33, and the control circuit module 1 addresses each dynamic blood glucose monitoring microneedle electrode 32 separately, and independently controls the working voltage applied to the dynamic blood glucose monitoring microneedle electrode 32. At the same time, a microcurrent detection module needs to be set in the control circuit module 1 to detect and record the current values ​​on different dynamic blood glucose monitoring microneedle electrodes 32 during the addressing process. The current value is correlated with the blood glucose concentration, and the blood glucose concentration can be converted using a pre-fitted relationship curve.

[0041] Similarly, in the above-mentioned dynamic blood glucose monitoring microneedle array patch 3, the second reference electrode can form a two-electrode system with each dynamic blood glucose monitoring microneedle electrode 32. However, in other embodiments, another second pair of electrodes (platinum electrodes can be used) in addition to the second reference electrode can be provided on the second flexible electrode sheet 31, and the first pair of electrodes is also connected to the control circuit module 1 through an independent second current path 33, thereby forming a three-electrode system with the dynamic blood glucose monitoring microneedle electrode 32. Both the two-electrode system and the three-electrode system can achieve the technical effect of the present invention.

[0042] There are a series of existing technologies for the above-mentioned dynamic blood glucose monitoring microneedle electrode 32, and in theory, any microneedle capable of measuring blood glucose can be used to achieve it. In the embodiment of the present invention, the dynamic blood glucose monitoring microneedle electrode 32 is based on a metal needle and has a 5-layer composite structure on the outside, that is, the surface of the metal needle is sequentially covered with a platinum layer, an o-phenylenediamine layer, a glucose oxidase layer, a chitosan layer, and a polyurethane layer.

[0043] In an embodiment of the present invention, a method for preparing a blood glucose sensitive working electrode for a dynamic blood glucose monitoring microneedle array patch is as follows: a metal needle is used as a working electrode, a silver / silver chloride electrode is used as a reference electrode, and a platinum electrode is used as a counter electrode, and a platinum layer is electroplated at a constant voltage of -0.3V for 300s in a 10mM H2PtCl6 / 1MHCl solution. Then, a platinum-plated metal needle is used as a working electrode, a silver / silver chloride electrode is used as a reference electrode, and a platinum electrode is used as a counter electrode, and an o-phenylenediamine layer is formed by electroplating at a constant voltage of +0.65V for 1200s in a 5mM o-phenylenediamine / 30mg / mL glucose oxidase (GOX) / 10mg / mL bovine serum albumin (BSA) solution. Then, the electrode covered with the o-phenylenediamine layer is immersed in 90mg / mL GOX / 30mg / mL BSA for 10min, 50μL glutaraldehyde is added to a 250mL brown cross-linking bottle, and the electrode is placed in a cross-linking bottle and cross-linked at 37°C for 15min to form a glucose oxidase layer. Next, the cross-linked electrode was immersed in a 1% chitosan solution for 30 seconds to form a chitosan layer. A 3mm diameter copper ring was made using a 0.5mm copper wire, and it was immersed in a 1% polyurethane solution to form a layer of polyurethane foam film inside the metal ring. The electrode was passed through the metal ring and taken out, so that the polyurethane foam film layer was partially transferred to the electrode surface to form a polyurethane layer.

[0044] The working method of the dynamic blood glucose monitoring microneedle array patch 3 is as follows: the dynamic blood glucose monitoring microneedle electrode 32 is used as the working electrode, the silver-silver chloride electrode is used as the reference and counter electrode, and a two-electrode system is formed (a platinum electrode can also be added to form a three-electrode system), and the working voltage between the working electrode and the silver / silver chloride reference is controlled by the control circuit module 1 to be +0.2-1.0V, preferably 0.5V. Glucose in the tissue fluid decomposes hydrogen peroxide under the action of the glucose oxidase layer of the blood glucose sensitive microneedle electrode, and the platinum layer catalyzes the decomposition of hydrogen peroxide to cause electron transfer under the working voltage, and the reaction current can be recorded by the microcurrent detection module in the circuit board. There is a high correlation between the glucose concentration in the tissue fluid and the glucose concentration in the blood, so the dynamic blood glucose monitoring microneedle array can characterize blood glucose changes to a large extent.

[0045] The currents measured by different blood glucose sensitive working electrodes in the dynamic blood glucose monitoring microneedle array patch 3 can be recorded separately, and different groups of data can be analyzed to obtain more accurate blood glucose monitoring results. The dynamic blood glucose monitoring microneedle array patch 3 can also be replaced after losing the blood glucose monitoring effect, so as to achieve the purpose of long-term dynamic blood glucose monitoring.

[0046] In addition, in the above-mentioned insulin-controlled-release microneedle array patch 2 and dynamic blood glucose monitoring microneedle array patch 3, all microneedles can be arranged arbitrarily, and can be various shapes such as m*n square array, circle, ring, etc. Insulin-controlled-release microneedle array patch 2 has only one reference electrode (or one reference electrode and one counter electrode), and the rest are insulin-controlled-release microneedle electrodes 22; similarly, dynamic blood glucose monitoring microneedle array patch 3 has only one reference electrode (or one reference electrode and one counter electrode), and the rest are dynamic blood glucose monitoring microneedle electrodes 32. Both patches and the control circuit module 1 are designed to be removable and replaceable.

[0047] The metal needles used to prepare the electrodes in the present invention are gold needles, platinum needles or stainless steel needles, etc., which are not limited.

[0048] In addition, the control circuit module 1 is the control center for realizing the overall function, but in addition to the individual addressing control of the electrodes on the two patches, other functions can be reasonably configured according to actual needs. For example, in one embodiment, an interactive display interface for displaying control parameters and detection parameters can be set in the control circuit module 1, and the user can directly perform human-computer interaction on the display screen to display and control the data. In another embodiment, a communication module for data interaction with an external device can be set in the control circuit module 1, and the relevant data can be sent to an external mobile device or other human-computer interactive system for display and control. In another embodiment, a feedback control module for feedback control of insulin release in the insulin controlled release microneedle array patch 2 according to the blood sugar concentration detected by the dynamic blood sugar monitoring microneedle array patch 3 can be set in the control circuit module 1.

[0049] The following is a specific example to illustrate the above Figure 1 to Figure 3 The specific implementation form and technical effect of the closed-loop insulin controlled-release system based on the microneedle array patch are shown.

[0050] Example

[0051] In this embodiment, the basic structures and connection methods of the control circuit module 1, the insulin controlled release microneedle array patch 2 and the dynamic blood glucose monitoring microneedle array patch 3 in the closed-loop insulin controlled release system based on the microneedle array patch are as described above and will not be repeated here. The specific preparation method and effect are as follows:

[0052] In the insulin controlled release microneedle array patch 2, the needle body substrate of the insulin controlled release microneedle electrode 22 is a stainless steel needle with a diameter of 140 μm. In a 1wt% sodium alginate, 35mM ferrous sulfate, 1000U insulin solution, a metal needle is used as a working electrode, a silver-silver chloride electrode is used as a reference electrode, and a platinum electrode is used as a counter electrode (it can also be a two-electrode system), and 30μA constant current electrolysis is performed for 60s, and the insulin controlled release microneedle is obtained after drying. The stainless steel needle can also be electroplated at -3mA constant current for 10s in a 0.4M copper sulfate solution to obtain a copper-plated stainless steel needle, and then the copper-plated stainless steel needle is electrolyzed at 30μA constant current for 60s in a 1wt% sodium alginate and 1000U insulin solution, and the insulin controlled release microneedle is obtained after drying. In this embodiment, the former is adopted, that is, the outer part of the needle body of the insulin controlled release microneedle electrode 22 is an insulin release gel cross-linked by trivalent iron ions.

[0053] Finally, an insulin controlled release microneedle array patch with independent current pathways was designed. Figure 2 As shown, the insulin controlled-release microneedle electrode 22 and a single silver / silver chloride reference microneedle are connected to the circuit patch through conductive silver paste, and then fixed and insulated with UV glue.

[0054] In the dynamic blood glucose monitoring microneedle array patch 3, the needle body base of the dynamic blood glucose monitoring microneedle electrode 32 is a stainless steel needle with a diameter of 140 μm. In 10 mM chloroplatinic acid / 1 M hydrochloric acid, the stainless steel needle is used as the working electrode, the silver / silver chloride electrode is used as the reference electrode, and the platinum electrode is used as the counter electrode. The platinum-plated stainless steel needle is obtained by constant voltage electroplating at -0.3 V for 300 s. Then, the platinum-plated stainless steel needle is used as the working electrode, the silver / silver chloride electrode is used as the reference electrode, and the platinum electrode is used as the counter electrode. In a 5 mM o-phenylenediamine / 30 mg / mL glucose oxidase (GOX) / 10 mg / mL bovine serum albumin (BSA) solution, the +0.65 V constant voltage electroplating is performed for 1200 s. Then, the electrode covered with the o-phenylenediamine layer is immersed in 90 mg / mL GOX / 30 mg / mL BSA for 10 min, 50 μL glutaraldehyde is added to a 250 mL brown cross-linking bottle, and the electrode is placed in the cross-linking bottle for cross-linking at 37°C for 15 min. Then, the electrode was immersed in a 1% chitosan solution for 30 seconds, and a copper ring with a diameter of 3 mm was made using a 0.5 mm copper wire. After being immersed in a 1% polyurethane solution, a layer of polyurethane foam film was formed inside the metal ring, and the electrode was taken out after passing through the film layer.

[0055] Finally, a dynamic blood glucose monitoring microneedle array patch with independent current pathways was designed. Figure 3 As shown, the dynamic blood glucose monitoring microneedle electrode 32, a single silver / silver chloride reference microneedle and a single platinum electrode microneedle are connected to the circuit patch through conductive silver paste, and then fixed and insulated with UV glue.

[0056] Finally, refer to Figure 1As shown, the insulin controlled release microneedle array patch and the dynamic blood glucose monitoring microneedle array patch are connected to the flexible circuit board through an interface. After the flexible circuit board is connected to a battery, the measured glucose concentration data is transmitted to the mobile phone via Bluetooth. When the glucose concentration exceeds the normal range, the insulin microneedle array patch can be released by applying a reduction voltage, thereby achieving stable control of blood glucose concentration.

[0057] The two patches in the above system were tested and verified respectively, and the experimental results are as follows:

[0058] 1) Glucose response experiment of microneedle for dynamic blood glucose monitoring:

[0059] For the dynamic blood glucose monitoring microneedle array patch 3, the metal microneedles coated with insulin-releasing gel cross-linked by trivalent iron ions were used as the working electrode, the standard Ag / AgCl was used as the reference electrode, and the standard platinum wire was used as the counter electrode to form a three-electrode system, which was immersed in a PBS solution with a pH of 7.2 to 7.4. The voltage difference between the working electrode and the reference electrode was controlled to be +0.5V by an electrochemical workstation. Each time 2mM glucose was added, the current response was measured. The final results are shown in Figure 4 As shown, the left figure is the glucose current response curve, and the right figure is the current-concentration correspondence.

[0060] In addition, the dynamic blood glucose microneedle monitoring response was tested using an electrochemical workstation and a flexible circuit board, respectively. The flexible circuit board played the role of the aforementioned control circuit module 1. In the same PBS solution with a pH of 7.2 to 7.4, the voltage difference between the working electrode and the reference electrode was controlled to be +0.5V. Each time 2mM glucose was added, the current response was measured. The glucose response curves measured by the electrochemical workstation and the flexible circuit board were shown in Figure 1. Figure 5 shown.

[0061] In addition, after the flexible circuit board is connected to the dynamic blood glucose monitoring microneedle patch, the patch contains four independent dynamic blood glucose monitoring microneedles. 2mM glucose is added to the PBS solution with pH = 7.2-7.4 each time, and the current response is as follows Figure 6 As shown (the four microneedles correspond to Channel 1, Channel 2, Channel 3, and Channel 4 respectively).

[0062] Then the dynamic blood glucose monitoring microneedle patch was inserted into the back of the rat, and the rat began to eat. The real-time monitored current signal was as follows Figure 7 shown.

[0063] 2) Response experiment of insulin controlled release microneedles:

[0064] For insulin controlled release microneedle array patch 2, the specific microneedle preparation process is as follows: in a solution containing 1% sodium alginate, 35mM ferrous sulfate and insulin, with a metal needle as the working electrode, a silver / silver chloride electrode as the reference electrode, and a platinum electrode as the counter electrode, electroplating at a constant current of 30μA for 60s, a layer of trivalent iron ion cross-linked insulin release gel is obtained on the surface of the metal needle. After standing in the air for 15 minutes, the gel loses water and tightly wraps around the needle body. Figure 8 The state diagrams of the ferric iron insulin gel after drying for 0min, 5min, 10min, and 15min are shown, and it can be seen that the gel gradually shrinks over time.

[0065] In addition, insulin release experiments were conducted based on the prepared microneedles: fluorescent microspheres were used instead of insulin molecules, and the fluorescence was observed under a fluorescence microscope after applying a -1.2 V reduction voltage for 5 min and 10 min. Fig. 9 As shown, the left picture is the initial state, the middle picture is the state after 5 minutes of reduction, and the right picture is the state after 10 minutes of reduction. It can be seen that the insulin controlled-release microneedle prepared by the present invention can achieve controlled release of insulin under the corresponding voltage.

[0066] The above-described embodiments are only some preferred implementations of the present invention, but are not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A closed-loop insulin controlled release system based on microneedle array patch, It is characterized in that It comprises a control circuit module (1), an insulin controlled-release microneedle array patch (2) and a dynamic blood glucose monitoring microneedle array patch (3); The insulin controlled-release microneedle array patch (2) comprises a first flexible electrode sheet (21), a first reference electrode and insulin controlled-release microneedle electrodes (22) distributed in an array on the first flexible electrode sheet (21), wherein the insulin controlled-release microneedle electrodes (22) are based on metal needles, and a gel network formed by metal ion cross-linking sodium alginate is covered on the surface of the metal needles, wherein insulin is encapsulated in the gel network; and all electrodes on the first flexible electrode sheet (21) are connected to the control circuit module (1) through an independent first current path (23), and the control circuit module (1) addresses each insulin controlled-release microneedle electrode (22) individually, and independently controls the reduction voltage applied to the insulin controlled-release microneedle electrode (22) for releasing insulin; The dynamic blood glucose monitoring microneedle array patch (3) comprises a second flexible electrode sheet (31), a second reference electrode and dynamic blood glucose monitoring microneedle electrodes (32) distributed in an array on the second flexible electrode sheet (31); and all electrodes on the second flexible electrode sheet (31) are connected to a control circuit module (1) via independent second current paths (33); the control circuit module (1) addresses each dynamic blood glucose monitoring microneedle electrode (32) individually, independently controls the working voltage applied to the dynamic blood glucose monitoring microneedle electrode (32), and records the current values ​​on different dynamic blood glucose monitoring microneedle electrodes (32) during the addressing process.

2. The closed-loop insulin controlled release system based on the microneedle array patch according to claim 1, It is characterized in that The preparation method of the insulin controlled-release microneedle electrode (22) is as follows: a metal needle is used as a working electrode, a silver / silver chloride electrode is used as a reference electrode, and a platinum electrode is used as a counter electrode; the three electrodes are immersed in a solution containing sodium alginate, insulin and ferrous sulfate, and insulin controlled-release microneedles covered with insulin gel are obtained by constant current electrolysis.

3. The closed-loop insulin controlled release system based on the microneedle array patch according to claim 1, It is characterized in that The preparation method of the insulin controlled-release microneedle electrode (22) is as follows: a copper-plated metal needle is used as a working electrode, a silver / silver chloride electrode is used as a reference electrode, and a platinum electrode is used as a counter electrode. The three electrodes are immersed in a solution containing sodium alginate and insulin, and insulin gel-covered insulin controlled-release microneedles are obtained by constant current electrolysis.

4. The closed-loop insulin controlled release system based on the microneedle array patch according to claim 1, It is characterized in that The reduction voltage applied to the insulin controlled-release microneedle electrode (22) for releasing insulin is -1.0 to -2.0V.

5. The closed-loop insulin controlled release system based on the microneedle array patch according to claim 1, It is characterized in that The dynamic blood glucose monitoring microneedle electrode (32) uses a metal needle as a substrate, and the surface of the metal needle is sequentially covered with a platinum layer, an o-phenylenediamine layer, a glucose oxidase layer, a chitosan layer and a polyurethane layer.

6. The closed-loop insulin controlled release system based on the microneedle array patch according to claim 1, It is characterized in that The working voltage applied to the dynamic blood glucose monitoring microneedle electrode (32) is +0.2 to +1.0V.

7. The closed-loop insulin controlled release system based on the microneedle array patch according to claim 1, It is characterized in that In addition to the first reference electrode, the first flexible electrode sheet (21) of the insulin controlled-release microneedle array patch (2) is also provided with a first pair of electrodes, which are also connected to the control circuit module (1) through an independent first current path (23), thereby forming a three-electrode system with the insulin controlled-release microneedle electrode (22).

8. The closed-loop insulin controlled release system based on the microneedle array patch according to claim 1, It is characterized in that In addition to the second reference electrode, the second flexible electrode sheet (31) of the dynamic blood glucose monitoring microneedle array patch (3) is also provided with a second pair of electrodes, which are also connected to the control circuit module (1) through an independent second current path (33), thereby forming a three-electrode system with the dynamic blood glucose monitoring microneedle electrode (32).

9. The closed-loop insulin controlled-release system based on a microneedle array patch as claimed in claim 1, It is characterized in that The control circuit module (1) has an interactive display interface for displaying control parameters and detection parameters, or has a communication module for data interaction with external equipment, or has a feedback control module for feedback controlling the release of insulin in the insulin controlled-release microneedle array patch (2) according to the blood glucose concentration detected by the dynamic blood glucose monitoring microneedle array patch (3).

10. The closed-loop insulin controlled release system based on a microneedle array patch according to any one of claims 1 to 9, It is characterized in that The metal needle is a gold needle, a platinum needle or a stainless steel needle.

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