Glucose diffusion control film solution for continuous blood glucose measurement biosensor, glucose diffusion control film for continuous blood glucose measurement biosensor comprising same, and continuous blood glucose measurement biosensor comprising same
By using a glucose diffusion control membrane solution containing hydrophilic and hydrophobic substances in the continuous blood glucose measurement biosensor, the problem of stability and difficulty in controlling glucose permeability and water absorption after the sensor is inserted into the human body is solved, achieving a more accurate blood glucose measurement.
Patent Information
- Application Number
- CN202380022083.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-02-16
- Filing Date
- 2023-02-01
- Publication Date
- 2025-01-24
AI Technical Summary
After the glucose diffusion control membrane in the existing continuous blood glucose measurement biosensor is inserted into the human body, it is difficult to ensure stability, and it is difficult to control the penetration and water absorption of glucose, affecting the accuracy of blood glucose measurement.
The glucose diffusion control membrane solution containing hydrophilic substances and hydrophobic substances is used, and the alipodus polyester base thermoplastic polyurethane is specifically used as hydrophilic substances. The permeability and water absorption of the control membrane.
Even if the substance that is verified by only biochemicals is inserted into the human body, it can ensure the stability of the biosensor, control the penetration and water absorption of glucose, thereby improving the accuracy of blood glucose measurement.
Smart Images
Figure CN119365540A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a glucose diffusion controlling membrane solution for a continuous blood glucose measurement biosensor, a glucose diffusion controlling membrane for a continuous blood glucose measurement biosensor containing the same, and a biosensor for continuous blood glucose measurement containing the same. More specifically, the present invention relates to a glucose diffusion controlling membrane solution for a continuous blood glucose measurement biosensor, which can ensure stability and control glucose permeability and water absorption even when only substances with verified biocompatibility are inserted into the human body, a glucose diffusion controlling membrane for a continuous blood glucose measurement biosensor containing the same, and a biosensor for continuous blood glucose measurement containing the same. Background Art
[0002] According to the 9th edition of the diabetes white paper "Global Diabetes Atlas (IDF DIABETES ATLAS)" published every two years by the International Diabetes Federation (IDF), there were 463 million (9.3%) people with diabetes aged 20 to 79 worldwide in 2019. This is an increase of 39 million people compared to the 425 million reported in 2017.
[0003] Moreover, as of 2019, there were 136 million people with diabetes over the age of 65, and one in every five elderly people suffered from diabetes.
[0004] What needs attention is that the incidence of diabetes is increasing rapidly every year.
[0005] Based on current trends, the number of people with diabetes worldwide is expected to reach 578 million (10.2%) in 2030, and will increase by 51% from 2019 to nearly 700 million (10.9%) in 2045.
[0006] Therefore, in the revised version of the 2021 guidelines of the American Diabetes Association (ADA), it is recommended that patients use a continuous glucose monitoring (CGM) system for multiple insulin treatments regardless of age or diabetes type, and it is clearly stated that it can also be used during hospitalization.
[0007] In particular, it helps correct the blood sugar pattern of glycemic patients and improve glycated hemoglobin, and blood sugar management through CGM is more effective when programs such as education and training and follow-up management are provided together.
[0008] In the 2021 diagnosis and treatment guidelines of the Korean Diabetes Association (KDA), it is recommended that all adults with type 1 diabetes use real-time continuous blood glucose monitors to regulate blood sugar and reduce the risk of hypoglycemia, and it is clearly stated that adults with type 2 diabetes receiving multiple insulin injections can use real-time continuous blood glucose monitors to regulate blood sugar.
[0009] Adults with type 2 diabetes who are treated only with other forms of insulin other than multiple insulin injections or oral medications can perform regular, real-time, continuous blood glucose monitoring to regulate blood glucose.
[0010] In addition, continuous blood glucose measurement can reduce the risk of hypoglycemia in pregnant women with type 1 diabetes, optimize blood glucose regulation, and improve obstetric performance, so it is recommended.
[0011] The sensor of the continuous blood glucose monitor may include a glucose diffusion control membrane at the outermost portion of the sensor.
[0012] The glucose diffusion control membrane does not have a negative impact on the human body when the sensor is inserted into the human body, preventing the sensor substances from being discharged into the human body. In addition, it can control the diffusion of glucose that flows into the human body.
[0013] As a person moves, the inflow rate of glucose flowing into the outermost part of the sensor through the glucose diffusion control membrane may increase, thereby making it difficult to accurately measure glucose in the blood.
[0014] Therefore, the present inventors conducted research to overcome this problem, and as a result, confirmed that when a glucose diffusion control membrane solution containing a mixture of specific hydrophilic substances and specific hydrophobic substances is used to prepare a glucose diffusion control membrane for a continuous blood glucose measurement biosensor, stability can be ensured even when only substances with verified biocompatibility are used for insertion into the human body, and glucose permeability and water absorption can be controlled, thereby completing the present invention. Summary of the invention
[0015] Technical issues
[0016] The present invention is conceived to solve the above-mentioned problems. The problem to be solved by the present invention is to provide a glucose diffusion controlling membrane solution for a continuous blood glucose measurement biosensor which can ensure stability and control glucose permeability and water absorption even when only substances with verified biocompatibility are inserted into the human body, a glucose diffusion controlling membrane for a continuous blood glucose measurement biosensor containing the same, and a biosensor for continuous blood glucose measurement containing the same.
[0017] Solutions to the problem
[0018] In order to solve the above-mentioned problems, the glucose diffusion control membrane solution of the present invention comprises a hydrophilic substance and a hydrophobic substance. Specifically, in the glucose diffusion control membrane solution for the continuous blood glucose measurement biosensor of the present invention, the hydrophilic substance may comprise an aliphatic polyester-based thermoplastic polyurethane, and the hydrophobic substance may comprise a styrene block copolymer.
[0019] In a preferred embodiment of the present invention, the specific gravity of the aliphatic polyester-based thermoplastic polyurethane according to the ASTM D792 determination method may be 1.0 to 1.2 g / cm 3 .
[0020] In a preferred embodiment of the present invention, the shore hardness of the aliphatic polyester-based thermoplastic polyurethane according to the ASTM D2240 test method may be 78-88A.
[0021] In a preferred embodiment of the present invention, the aliphatic polyester-based thermoplastic polyurethane may have a flexural modulus of 2400-3400 psi measured according to ASTM D790.
[0022] In a preferred embodiment of the present invention, for aliphatic polyester-based thermoplastic polyurethane, according to the ASTM D412 measurement method, in a dry state, the ultimate tensile can be 1700 to 2700 psi, and in a wet state, the ultimate tensile can be 900 to 1900 psi.
[0023] In a preferred embodiment of the present invention, for aliphatic polyester-based thermoplastic polyurethane, according to the ASTM D412 measurement method, in a dry state, the ultimate elongation can be 540 to 1540 psi, and in a wet state, the ultimate elongation can be 320 to 920 psi.
[0024] In a preferred embodiment of the present invention, the specific gravity of the styrene block copolymer according to the ISO 1183-1 determination method may be 0.9 to 1.1 g / cm 3 .
[0025] In a preferred embodiment of the present invention, the shore hardness of the styrene block copolymer according to the ISO 48-4 measurement method may be 60-80A.
[0026] In a preferred embodiment of the present invention, the tensile strength of the styrene block copolymer measured according to ISO 37 may be 8.2 to 10.2 MPa.
[0027] In a preferred embodiment of the present invention, the elongation at break of the styrene block copolymer measured according to ISO 37 may be 414-614%.
[0028] In a preferred embodiment of the present invention, the tear strength of the styrene block copolymer measured according to ISO 34-1, preferably ISO 34-1 method B (b) (Graves) may be 15 to 25 N / mm.
[0029] In a preferred embodiment of the present invention, the weight ratio of the hydrophilic substance to the hydrophobic substance may be 1:0.1-4.
[0030] On the other hand, the glucose diffusion controlling membrane for a continuous blood glucose measuring biosensor of the present invention can be prepared by drying the glucose diffusion controlling membrane for a continuous blood glucose measuring biosensor of the present invention solution.
[0031] Furthermore, the continuous blood glucose measurement biosensor of the present invention may include the glucose diffusion control membrane for the continuous blood glucose measurement biosensor of the present invention.
[0032] Effects of the Invention
[0033] The glucose diffusion controlling membrane solution for a continuous blood glucose measurement biosensor, the glucose diffusion controlling membrane for a continuous blood glucose measurement biosensor containing the same, and the continuous blood glucose measurement biosensor containing the same of the present invention can ensure stability and control glucose permeability and water absorption even when inserted into the human body using only substances with verified biocompatibility. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 The results are as follows: the current intensity over time of the test sensors using the glucose diffusion controlling membrane solutions prepared in Examples 1 to 3, the hydrophilic solution prepared in Preparation Example 1, and the hydrophobic solution prepared in Preparation Example 2, respectively.
[0035] Figure 2 The following are confirmation results of the current density over time of the test sensors using the glucose diffusion controlling membrane solution prepared in Example 1 and the glucose diffusion controlling membrane solution prepared in Comparative Example 1, respectively. DETAILED DESCRIPTION
[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement the present invention. The present invention can be implemented in a variety of different forms and is not limited to the embodiments described herein. In the drawings, parts not related to the description are omitted in order to clearly illustrate the present invention. In the entire specification, the same or similar structural elements are marked with the same reference numerals.
[0037] The continuous blood glucose measurement biosensor of the present invention may include the glucose diffusion control membrane for the continuous blood glucose measurement biosensor of the present invention. In this case, the glucose diffusion control membrane for the continuous blood glucose measurement biosensor of the present invention may be prepared by drying the glucose diffusion control membrane solution for the continuous blood glucose measurement biosensor of the present invention described later.
[0038] The biosensor for continuous blood glucose measurement of the present invention is an electrochemical sensor for measuring glucose in blood.
[0039] Such a biosensor for continuous blood glucose measurement may include, for example, electrodes, an insulator, a substrate, an electron transfer medium, an enzyme layer containing an enzyme and a cross-linking agent, and a glucose diffusion control membrane.
[0040] The enzyme layer may include an enzyme and a redox polymer that can redox a liquid biological sample. It may be an enzyme layer for an electrochemical biosensor that includes an electron transfer medium. Redox enzymes are a general term for enzymes that catalyze redox reactions in organisms. In the present invention, it means an enzyme that reacts with the object substance to be measured, for example, in the case of a biosensor, to reduce the object substance to be measured. The enzyme reduced in this way reacts with the electron transfer medium, and the object substance is quantified by measuring signals such as current changes that occur at this time. The redox enzyme that can be used in the present invention can be one or more selected from the group consisting of various dehydrogenases, oxidases, esterases, etc., and according to the redox or detection object substance, an enzyme that uses the object substance as a substrate can be selected from the enzyme group.
[0041] More specifically, the above-mentioned oxidoreductase can be one or more selected from the group consisting of glucose dehydrogenase, glutamate dehydrogenase, glucose oxidase, cholesterol oxidase, cholesterol esterase, lactate oxidase, ascorbic acid oxidase, alcohol oxidase, alcohol dehydrogenase, bilirubin oxidase, uricase, etc.
[0042] Furthermore, the electron transfer medium may include at least one selected from a metal-containing complex and an organic conducting salt.
[0043] As metal-containing complexes, ruthenium complexes, osmium complexes, ferricyanide complexes, etc., which are Group 8 elements, may be included. As organic conductive salts, ferrocene, quinone, quinone derivatives, methylene blue, etc. may be included.
[0044] On the other hand, the oxidoreductase may also contain a cofactor that plays a role in storing hydrogen that the oxidoreductase removes from the target substance to be measured (e.g., the target substance), for example, it may be one or more selected from the group consisting of flavin adenine dinucleotide (FAD), nicotinamide adenine dinucleotide (NAD), pyrroloquinoline quinone (PQQ), etc.
[0045] In addition, the enzyme layer may also contain one or more additives selected from the group consisting of cross-linking agents, surfactants, water-soluble polymers, quaternary ammonium salts, fatty acids, thickeners, etc., to act as a dispersant during reagent dissolution, a binder during reagent preparation, a stabilizer for long-term storage, etc.
[0046] The electrodes may include two electrodes such as a working electrode and a counter electrode, or three electrodes such as a working electrode, a counter electrode, and a reference electrode. In one example, the biosensor according to the present invention may be an electrochemical biosensor produced by coating a substrate having at least two, preferably two or three electrodes with an enzyme solution containing an enzyme that can oxidize and reduce glucose, a cross-linking agent, and an electron transfer mediator, and then drying the substrate. For example, as an electrochemical biosensor, a planar electrochemical biosensor may be provided, wherein a working electrode, a counter electrode, and a reference electrode are arranged on the same surface of a substrate, an enzyme layer according to the present invention is stacked on the working electrode, an insulator is stacked on the substrate and electrodes (working electrode, counter electrode, reference electrode), and a glucose diffusion control membrane is stacked on the above electrodes.
[0047] As a specific embodiment, the substrate may be formed of one or more materials selected from the group consisting of polydimethylsiloxane (PDMS), polyimide (PI) and polyethylene terephthalate (PET).
[0048] Also, carbon, gold, platinum, silver or electrodes may be used as the working electrode.
[0049] Furthermore, for an electrochemical biosensor having two electrodes, the counter electrode serves as a reference electrode, and thus a gold, platinum, silver or silver / silver chloride electrode can be used as the counter electrode. For an electrochemical biosensor having three electrodes including a reference electrode, a silver / silver chloride electrode can be used as the reference electrode, and a carbon electrode can be used as the counter electrode.
[0050] As a non-limiting example, in the case of two electrodes, the counter electrode functions as a reference electrode and silver chloride or silver may be used. In the case of three electrodes, silver chloride or silver is used as the reference electrode and a carbon electrode may be used as the counter electrode.
[0051] On the other hand, the glucose diffusion control membrane solution for the continuous blood glucose measurement biosensor of the present invention contains a hydrophilic substance and a hydrophobic substance. As such, the glucose diffusion control membrane solution for the continuous blood glucose measurement biosensor of the present invention contains both a hydrophilic substance and a hydrophobic substance, and even in the environment inside the human body, the glucose permeability control is excellent, and the glucose sensing sensitivity can be achieved. When the glucose diffusion control membrane solution for the continuous blood glucose measurement biosensor of the present invention contains only a hydrophilic substance, there may be a problem that glucose excessively permeates the outermost part of the continuous blood glucose measurement biosensor, resulting in a decrease in the performance of the sensor. When it contains only a hydrophobic substance, there may be a problem that glucose does not permeate the outermost part of the continuous blood glucose measurement biosensor, resulting in an inability to sense glucose.
[0052] First, as a hydrophilic substance, an aliphatic polyester-based thermoplastic polyurethane may be included.
[0053] Specifically, the specific gravity of the aliphatic polyester-based thermoplastic polyurethane according to the ASTM D792 measurement method is 1.0 to 1.2 g / cm 3 , preferably, it can be 1.1 to 1.16 g / cm 3 .
[0054] Furthermore, the aliphatic polyester-based thermoplastic polyurethane has a Shore hardness of 78 to 88A, preferably 81 to 85A, according to the ASTM D2240 measurement method.
[0055] Furthermore, the aliphatic polyester-based thermoplastic polyurethane has a flexural modulus of 2400 to 3400 psi, preferably 2700 to 3100 psi, measured according to ASTM D790.
[0056] Furthermore, the ultimate tensile strength of the aliphatic polyester-based thermoplastic polyurethane in a dry state is 1700 to 2700 psi according to the ASTM D412 test method, and preferably 2000 to 2400 psi.
[0057] Furthermore, the ultimate tensile strength of the aliphatic polyester-based thermoplastic polyurethane in a wet state is 900 to 1900 psi according to the ASTM D412 test method, and preferably 1200 to 1600 psi.
[0058] Furthermore, the aliphatic polyester-based thermoplastic polyurethane has an ultimate elongation of 540 to 1540 psi, preferably 840 to 1240 psi, in a dry state according to ASTM D412.
[0059] Furthermore, the aliphatic polyester-based thermoplastic polyurethane has an ultimate elongation of 320 to 920 psi, preferably 520 to 720 psi, in a wet state according to ASTM D412.
[0060] Then, as the hydrophobic substance, a styrene block copolymer may be included.
[0061] Specifically, the specific gravity of the styrene block copolymer according to the ISO 1183-1 measurement method is 0.9 to 1.1 g / cm 3 , preferably, it can be 1.0 to 1.05 g / cm 3 .
[0062] Furthermore, the shore hardness of the styrene block copolymer measured according to ISO 48-4 is 60 to 80A, preferably 65 to 75A.
[0063] Furthermore, the tensile strength of the styrene block copolymer measured according to ISO 37 is 8.2 to 10.2 MPa, preferably 8.7 to 9.7 MPa.
[0064] Furthermore, the elongation at break of the styrene block copolymer measured according to ISO 37 is 414 to 614%, preferably 464 to 564%.
[0065] Furthermore, the tear strength of the styrene block copolymer measured by ISO 34-1, preferably ISO 34-1 method B (b) (Graves) is 15 to 25 N / mm, preferably 18 to 22 N / mm.
[0066] On the other hand, the weight ratio of the hydrophilic substance and the hydrophobic substance in the glucose diffusion control membrane solution for the continuous blood glucose measurement biosensor of the present invention is 1:0.1-4, preferably 1:0.1-3, and more preferably 1:0.15-0.8. When the weight ratio is less than 1:0.1, there is a possibility that glucose excessively permeates the outermost part of the continuous blood glucose measurement biosensor, thereby causing the performance of the sensor to deteriorate. When the weight ratio is greater than 1:4, there is a possibility that glucose does not permeate the outermost part of the continuous blood glucose measurement biosensor, thereby causing the problem of being unable to sense glucose.
[0067] Furthermore, the glucose diffusion control membrane solution for the continuous blood glucose measurement biosensor of the present invention may further include an organic solvent, and the concentration of the glucose diffusion control membrane solution for the continuous blood glucose measurement biosensor of the present invention may be adjusted by the organic solvent. As the organic solvent of the present invention, any solvent may be used as long as it is an organic solvent used in the field, preferably, it may include one or more selected from chloroform, cyclohexanone, cyclopentanone, dimethylacetamide, dimethylformamide, dioxane, methylene chloride, trichloroethane, tetrahydrofuran, xylene and toluene, and more preferably, it may include tetrahydrofuran.
[0068] Hereinafter, the present invention will be described by the following examples. At this time, the following examples are provided only for the purpose of illustrating the invention, and the scope of rights of the present invention is not limited to the following examples.
[0069] Preparation Example 1: Preparation of hydrophilic solution
[0070] 2000 mg of aliphatic polyester-based thermoplastic polyurethane (HP-93A-100, Lubrizol) as a hydrophilic substance and 50 ml of tetrahydrofuran as an organic solvent were placed in a homogenizer and dissolved to prepare a hydrophilic solution with a concentration of 40 mg / mL.
[0071] Preparation Example 2: Preparation of hydrophobic solution
[0072] 2000 mg of a styrene block copolymer (TM7APO, KRAIBURG) as a hydrophobic substance and 50 ml of tetrahydrofuran as an organic solvent were placed in a homogenizer and dissolved for 30 minutes to prepare a hydrophobic solution with a concentration of 40 mg / mL.
[0073] Experimental Example 1: Cytotoxicity Experiment
[0074] The hydrophilic solution prepared in Preparation Example 1 and the hydrophobic solution prepared in Preparation Example 2 were evaluated for cytotoxicity according to the ISO 10993-5 evaluation method. As a result, it was confirmed that both the hydrophilic solution prepared in Preparation Example 1 and the hydrophobic solution prepared in Preparation Example 2 were non-cytotoxic.
[0075] Experimental Example 2: Skin Sensitization Experiment
[0076] The hydrophilic solution prepared in Preparation Example 1 and the hydrophobic solution prepared in Preparation Example 2 were respectively subjected to skin sensitization evaluation according to the ISO 10993-10 evaluation method. As a result, it was confirmed that neither the hydrophilic solution prepared in Preparation Example 1 nor the hydrophobic solution prepared in Preparation Example 2 caused irritation or skin sensitivity.
[0077] Experimental Example 3: Systemic Toxicity Test
[0078] The hydrophilic solution prepared in Preparation Example 1 and the hydrophobic solution prepared in Preparation Example 2 were evaluated for systemic toxicity according to the evaluation method of ISO 10993-11. As a result, it was confirmed that both the hydrophilic solution prepared in Preparation Example 1 and the hydrophobic solution prepared in Preparation Example 2 had no systemic toxicity.
[0079] Experimental Example 4: Blood Compatibility Experiment
[0080] The hydrophilic solution prepared in Preparation Example 1 and the hydrophobic solution prepared in Preparation Example 2 were respectively evaluated for blood compatibility according to the ISO 10993-4 evaluation method. As a result, it was confirmed that both the hydrophilic solution prepared in Preparation Example 1 and the hydrophobic solution prepared in Preparation Example 2 were blood compatible.
[0081] Example 1: Preparation of Glucose Diffusion Control Membrane Solution for Continuous Blood Glucose Determination Biosensor
[0082] 16 mL of the hydrophilic solution prepared in Preparation Example 1 and 4 mL of the hydrophobic solution prepared in Preparation Example 2 were added to a stirrer and stirred to prepare a glucose diffusion control membrane solution having a concentration of 40 mg / mL. At this time, the glucose diffusion control membrane solution contained aliphatic polyester-based thermoplastic polyurethane (HP-93A-100, Lubrizol) and styrene block copolymer (TM7APO, KRAIBURG) at a weight ratio of 1:0.25.
[0083] Example 2: Preparation of Glucose Diffusion Control Membrane Solution for Continuous Blood Glucose Determination Biosensor
[0084] 10 mL of the hydrophilic solution prepared in Preparation Example 1 and 10 mL of the hydrophobic solution prepared in Preparation Example 2 were added to a stirrer and stirred to prepare a glucose diffusion control membrane solution having a concentration of 40 mg / mL. At this time, the glucose diffusion control membrane solution contained aliphatic polyester-based thermoplastic polyurethane (HP-93A-100, Lubrizol) and styrene block copolymer (TM7APO, KRAIBURG) at a weight ratio of 1:1.
[0085] Example 3: Preparation of Glucose Diffusion Control Membrane Solution for Continuous Blood Glucose Determination Biosensor
[0086] 4 mL of the hydrophilic solution prepared in Preparation Example 1 and 16 mL of the hydrophobic solution prepared in Preparation Example 2 were added to a stirrer and stirred to prepare a glucose diffusion control membrane solution having a concentration of 40 mg / mL. At this time, the glucose diffusion control membrane solution contained aliphatic polyester-based thermoplastic polyurethane (HP-93A-100, Lubrizol) and styrene block copolymer (TM7APO, KRAIBURG) at a weight ratio of 1:4.
[0087] Preparation Example 1: Preparation of test sensor
[0088] (1) An electron transfer mediator, an enzyme, and a cross-linking agent were mixed at a volume ratio of 4:4:1 to prepare an enzyme solution. In this case, an osmium complex was used as the electron transfer mediator, and glutamate dehydrogenase was used as the enzyme.
[0089] (2) A test electrode consisting of a working electrode (using a carbon electrode), a reference electrode (using an AgCl electrode), and a counter electrode (using a carbon electrode) was prepared, and 2.5 μL of the enzyme solution was drop-casted on the working electrode of the test electrode.
[0090] (3) Dry the test electrode in a 35°C dry oven for 30 minutes.
[0091] (4) A masking film is attached to the working electrode, reference electrode and counter electrode of the test electrode, and the glucose diffusion control membrane solution prepared in Examples 1 to 3, the hydrophilic solution prepared in Preparation Example 1, and the hydrophobic solution prepared in Preparation Example 2 are drop-casted on the masking film respectively, and then dried to prepare test sensors each having a glucose diffusion control membrane.
[0092] Experimental Example 5: Determination of Glucose Osmolarity
[0093] 2 mL of PBS solution was placed in a glass cell for electrochemical measurement, and the test sensors prepared in Preparation Example 1 were respectively supported in the PBS solution.
[0094] Glucose was supplied to the PBS solution using a glucose stock solution (in 10 mM PBS solution) to adjust the glucose concentration to 50, 100, 200, 300, 400, and 500 mg / dL. The conditions were then measured using a potentiostat (Multi-Palmsens 4, applied voltage: 0.3 V) under chronoamperometry (CA) conditions. The results are shown in Figure 1 middle.
[0095] If available from Figure 1 It was confirmed that the change in the current value due to the change in glucose concentration was greater in the order of the hydrophilic solution prepared in Preparation Example 1, the glucose diffusion controlling membrane solution prepared in Example 1, the glucose diffusion controlling membrane solution prepared in Example 2, and the glucose diffusion controlling membrane solution prepared in Example 3. In addition, when only the hydrophobic solution prepared in Preparation Example 2 was used, there was almost no change in the current value due to the change in glucose concentration.
[0096] From these results, it was confirmed that the glucose sensing sensitivity can be selectively controlled by controlling the ratio of the hydrophobic substance contained in the glucose diffusion control membrane.
[0097] Experimental Example 6: Determination of water absorption
[0098] 3 mL of each of the glucose diffusion controlling membrane solutions prepared in Examples 1 to 3, the hydrophilic solution prepared in Preparation Example 1, and the hydrophobic solution prepared in Preparation Example 2 were dispensed into glass petri dishes and dried at room temperature (25° C.) for 24 hours to prepare glucose diffusion controlling membranes, and the initial weights were measured.
[0099] The prepared glucose diffusion control membranes were supported in ultrapure water (DI water) for 24 hours, and the final weights were measured.
[0100] The water absorption rates of the glucose diffusion controlling membrane solutions prepared in Examples 1 to 3, the hydrophilic solution prepared in Preparation Example 1, and the hydrophobic solution prepared in Preparation Example 2 were calculated using the measured initial weight and final weight, and are shown in Table 1 below.
[0101] Table 1
[0102] distinguish Initial weight (mg) Final weight (mg) Water absorption (%) Example 1 109.5 188.5 72.1 Example 2 107.6 152.0 41.3 Example 3 109.2 123.3 12.9 Preparation Example 1 106.8 200.3 87.5 Preparation Example 2 112.0 112.6 0.6
[0103] As can be confirmed from Table 1, it can be confirmed that the water absorption rate is higher in the order of the hydrophilic solution prepared in Preparation Example 1, the glucose diffusion controlling membrane solution prepared in Example 1, the glucose diffusion controlling membrane solution prepared in Example 2, and the glucose diffusion controlling membrane solution prepared in Example 3. In addition, when only the hydrophobic solution prepared in Preparation Example 2 was used, water was hardly absorbed.
[0104] From these results, it was confirmed that the water absorption rate can be selectively controlled by controlling the ratio of the hydrophobic substance contained in the glucose diffusion control membrane.
[0105] Comparative Preparation Example 1: Preparation of Hydrophobic Solution
[0106] 2000 mg of aliphatic polyester-based thermoplastic polyurethane (SG-80A, Lubrizol) as a hydrophobic substance and 50 ml of tetrahydrofuran as an organic solvent were placed in a homogenizer and dissolved for 60 minutes to prepare a hydrophobic solution with a concentration of 40 mg / mL.
[0107] As can be confirmed in the process of preparing the hydrophobic solution of Comparative Preparation Example 1, it can be confirmed that the time for dissolving the styrene block copolymer used in Preparation Example 2 is 30 minutes, while the time for dissolving the aliphatic polyester-based thermoplastic polyurethane used in Comparative Preparation Example 1 is 60 minutes. Therefore, it can be confirmed that when preparing the glucose diffusion control membrane solution, using the hydrophobic solution prepared in Preparation Example 2 as the hydrophobic solution shortens the preparation time compared to using the hydrophobic solution prepared in Comparative Preparation Example 1, and it can be confirmed that it is easy to mass produce.
[0108] Comparative Example 1: Preparation of Glucose Diffusion Control Membrane Solution for Continuous Blood Glucose Determination Biosensor
[0109] 16 mL of the hydrophilic solution prepared in Preparation Example 1 and 4 mL of the hydrophobic solution prepared in Comparative Preparation Example 1 were added to a stirrer and stirred to prepare a glucose diffusion control membrane solution having a concentration of 40 mg / mL. At this time, the glucose diffusion control membrane solution contained aliphatic polyester-based thermoplastic polyurethane (HP-93A-100, Lubrizol) and aliphatic polyester-based thermoplastic polyurethane (SG-80A, Lubrizol) at a weight ratio of 1:0.25.
[0110] Preparation Example 2: Preparation of test sensor
[0111] (1) An electron transfer mediator, an enzyme, and a cross-linking agent were mixed at a volume ratio of 4:4:1 to prepare an enzyme solution. In this case, an osmium complex was used as the electron transfer mediator, and glutamate dehydrogenase was used as the enzyme.
[0112] (2) A test electrode consisting of a working electrode (using a carbon electrode), a reference electrode (using an AgCl electrode), and a counter electrode (using a carbon electrode) was prepared, and 2.5 μL of the enzyme solution was drop-casted on the working electrode of the test electrode.
[0113] (3) Dry the test electrode in a 35°C dry oven for 30 minutes.
[0114] (4) A masking film is attached to the working electrode, reference electrode and counter electrode of the test electrode, and the glucose diffusion controlling membrane solution prepared in Example 1 and the glucose diffusion controlling membrane solution prepared in Comparative Example 1 are drop-casted on the masking films respectively, followed by drying to prepare test sensors each having a glucose diffusion controlling membrane.
[0115] Experimental Example 7: Determination of Glucose Osmolarity
[0116] 2 mL of PBS solution was placed in a glass cell for electrochemical measurement, and the test sensors prepared in Preparation Example 2 were respectively supported in the PBS solution.
[0117] Glucose was supplied to the PBS solution using a glucose stock solution (in 10 mM PBS solution) to a glucose concentration of 200 mg / dL. The conditions were then measured using a potentiostat (Multi-Palmsens 4, applied voltage: 0.3 V) under chronoamperometry (CA) conditions. The results are shown in Figure 2 middle.
[0118] If available from Figure 2 It was confirmed that the current density measured when the glucose diffusion controlling membrane solution prepared in Example 1 was used was higher than that when the glucose diffusion controlling membrane solution prepared in Comparative Example 1 was used.
[0119] Simple modifications or changes of the present invention can be easily implemented by ordinary technicians in the technical field to which the present invention belongs, and these modifications or changes can be regarded as included in the scope of the present invention.
Claims
1. A glucose diffusion control membrane solution for a continuous blood glucose measurement biosensor, comprising a hydrophilic substance and a hydrophobic substance, characterized in that: The hydrophilic substance comprises aliphatic polyester-based thermoplastic polyurethane, The hydrophobic substance includes a styrene block copolymer.
2. The glucose diffusion control membrane solution for continuous blood glucose measurement biosensor according to claim 1, characterized in that: The specific gravity of the aliphatic polyester-based thermoplastic polyurethane according to the ASTM D792 measurement method is 1.0 to 1.2 g / cm 3 , according to the ASTM D2240 determination method, the Shore hardness is 78 to 88A, The specific gravity of the styrene block copolymer measured according to ISO 1183-1 is 0.9 to 1.1 g / cm 3 The Shore hardness according to ISO48-4 measurement method is 60~80A.
3. The glucose diffusion control membrane solution for continuous blood glucose measurement biosensor according to claim 2, characterized in that: For the above-mentioned aliphatic polyester-based thermoplastic polyurethane, The bending modulus according to ASTM D790 is 2400~3400psi. According to the ASTM D412 test method, the ultimate tensile strength is 1700-2700 psi in a dry state and 900-1900 psi in a wet state. According to the ASTM D412 test method, the ultimate elongation is 540 to 1540 psi in a dry state, and the ultimate elongation is 320 to 920 psi in a wet state.
4. The glucose diffusion control membrane solution for continuous blood glucose measurement biosensor according to claim 2, characterized in that: For the above styrene block copolymer, The tensile strength according to ISO 37 is 8.2-10.2 MPa. The elongation at break according to ISO 37 is 414-614%. The tear strength measured by the ISO 34-1 method is 15 to 25 N / mm.
5. The glucose diffusion control membrane solution for continuous blood glucose measurement biosensor according to claim 1, characterized in that: The weight ratio of the hydrophilic substance to the hydrophobic substance is 1:0.1-4.
6. A glucose diffusion control membrane for a continuous blood glucose measurement biosensor, characterized in that: The biosensor according to claim 1 is prepared by drying the glucose diffusion control membrane solution.
7. A biosensor for continuous blood glucose measurement, characterized in that: Comprising the glucose diffusion control membrane according to claim 6.