Difunctional polymer film and application thereof in preparation of potentiometric sensor

Abstract

The invention belongs to the field of polymer membrane ion selective electrode sensitive membranes, and particularly relates to a bifunctional polymer membrane and application thereof in preparation of a potentiometric sensor. The bifunctional polymer membrane comprises the following components in parts by weight: 0.05-10 parts of an ion exchanger and 10-90 parts of a sensitive membrane matrix of a grafted ion carrier, wherein the sensitive membrane matrix of the grafted ion carrier is a fluorine-containing methacrylate polymer of the grafted ion carrier. According to the method disclosed by the invention, a novel fluorine-based sensing membrane ion selective electrode is constructed, so that the problem of biological fouling when a sensitive membrane of a traditional polymer membrane ion selective electrode is applied to a biological fluid is avoided, and meanwhile, the problems of electrode performance reduction and toxicity to a to-be-detected object caused by reagent seepage of the traditional sensitive membrane are eliminated; and the stability, the service life and the biocompatibility of the electrode are effectively improved. The method is of great significance in application of a potentiometric sensor of a polymer sensitive film substrate in biomedical equipment.

Description

Technical Field

[0001] The invention belongs to the field of polymer membrane ion selective electrode sensitive membranes, and specifically relates to a bifunctional polymer membrane with the advantages of low toxicity and anti-fouling and its application in the preparation of potential type sensors. Background Art

[0002] As a common type of electrochemical sensor, polymer membrane ion selective electrodes (ISEs) have the characteristics of simple operation, low cost, low energy consumption, and excellent detection performance. They have been widely used in environmental monitoring, clinical diagnosis, food testing and other fields. Especially in clinical diagnosis, polymer membrane ISEs potentiometric method has become a popular method for clinical analysis of Na + , K + , Ca 2+ and Cl - At present, this type of electrode has been widely used for the direct determination of various ions in whole blood, serum, urine, tissue, intracellular fluid and their dilutions.

[0003] In recent years, the development of wearable and implantable healthcare devices based on polymer membrane ISEs to measure the ion content in biological fluids in real time as a non-invasive method for diagnosing diseases has attracted widespread attention. The polymer sensitive membranes in wearable and implantable ISEs must be biocompatible, including not causing toxicity problems to the object and the sensitive membrane needs to be anti-fouling. However, most of the polymer sensitive membranes reported so far are prepared based on plasticized polyvinyl chloride (PVC) matrix. During the preparation process, a large amount of plasticizers need to be added to reduce the glass transition temperature of PVC, which inevitably leads to a decrease in biocompatibility. The surface of traditional PVC sensitive membranes is hydrophobic. When the electrode is in continuous contact with biological fluids for a long time, there is usually a problem of biofouling, such as proteins, lipids and cells adsorbed on the sensor surface. In addition, the leaching of plasticizers in the membrane phase will cause certain physiological toxicity and limit the service life of the sensor. The biofouling and toxicity problems of polymer sensitive membranes are problems that ISEs must face when they are applied in the biomedical field.

[0004] In order to promote the development of ISEs in biomedical applications, it is crucial to develop polymer membrane ion selective electrodes with good biocompatibility. At present, the research work on improving the biocompatibility of polymer membrane potential sensors is mainly focused on improving the anti-fouling ability of the electrode, and there is little research on the biotoxicity of polymer sensitive membranes.

[0005] Fluorinated polymers are biocompatible materials with wide applications in the biomedical field. However, most commercially available fluorinated polymers are not suitable for the manufacture of polymer sensitive membranes due to their high glass transition temperature. The active components (ion carriers, ion exchangers) in the sensitive membrane phase are incompatible with fluorinated polymers, which affects the response performance of the electrode. In addition, there is currently no method that can simultaneously achieve anti-biofouling and reduce the toxicity of polymer sensitive membranes. Therefore, designing low-surface-energy fluorinated polymers and solving the compatibility problem of components to construct a low-toxic and anti-fouling bifunctional polymer membrane ISEs is of great significance for expanding the application of ISEs in biomedicine. Summary of the invention

[0006] The purpose of the present invention is to provide a fluorine-containing polymer sensitive membrane with low surface energy, to construct a dual-function polymer membrane potential sensor with low toxicity and anti-fouling advantages and its application.

[0007] To achieve the above object, the technical solution adopted by the present invention is: A bifunctional polymer membrane comprises, by weight, 0.05-10 parts of an ion exchanger and 10-90 parts of a sensitive membrane matrix of a grafted ion carrier; wherein the sensitive membrane matrix of the grafted ion carrier is a fluorine-containing methacrylate polymer of the grafted ion carrier; the fluorine-containing methacrylate polymer of the grafted ion carrier is obtained by free radical polymerization of a fluorine-containing methacrylate monomer, a monomer with a low glass transition temperature and a polymerizable ion carrier, or by the reaction of a fluorine-containing methacrylate monomer with a low glass transition temperature and a polymerizable ion carrier; wherein the monomer with a low glass transition temperature is a methacrylate or acrylate monomer with a low glass transition temperature.

[0008] The fluorine-containing methacrylate monomer and the monomer having a low glass transition temperature are mixed in a molar ratio of 1-50:10-80.

[0009] The bifunctional polymer membrane is a mixture of a sensitive membrane matrix grafted with an ion carrier and an ion exchanger, which is fully dissolved in a non-polar organic solvent and evaporated naturally at room temperature.

[0010] The ion exchanger is one or more fluorine-containing ion exchangers.

[0011] The ion exchanger is sodium tetrakis(3,5-di(trifluoromethyl)phenyl)borate, potassium tetrakis(3,5-di(trifluoromethyl)phenyl)borate or sodium tetrakis(3,5-di(perfluorohexyl)phenyl)borate.

[0012] The sensitive membrane matrix of the grafted ion carrier is prepared by mixing a fluorine-containing methyl acrylate monomer and a monomer with a low glass transition temperature, or a fluorine-containing methyl acrylate monomer with a low glass transition temperature with a covalently linked ion carrier in an organic solvent, stirring evenly, adding an initiator, and thermally initiating polymerization at 60-90° C. for 8-24 hours to obtain a transparent solution; dropping the transparent solution into a cold polar organic solvent to form a gel-like precipitate; dissolving the obtained copolymer precipitate in dioxane, then precipitating the precipitate with ultrapure water, and vacuum drying the obtained white viscous copolymer at room temperature for 12-48 hours to obtain the target product.

[0013] The covalently linked ion carrier is a polymerizable ion carrier containing a vinyl functional group; the added amount thereof accounts for 0.5-20 wt % of the total mass percentage of the polymerization reaction monomers.

[0014] When the monomer is a fluorine-containing methacrylate monomer and a monomer with a low glass transition temperature (an acrylic monomer with a low glass transition temperature), the two monomers are mixed in a molar fraction ratio of 1-50:10-80.

[0015] The fluorine-containing methacrylate monomer is dodecafluoroheptyl methacrylate and / or tridecafluorooctyl methacrylate; The low glass transition temperature monomer is n-butyl acrylate, lauryl methacrylate, isodecyl acrylate, n-decyl methacrylate and / or isooctyl acrylate.

[0016] The initiator can be azobisisobutyronitrile (AIBN), dimethyl azobisisobutyrate (AMBME), azobisisoheptanenitrile (ABVN), di-tert-butyl peroxide (DTBP) and diisopropylbenzene peroxide (DCP), etc., and the added amount thereof is 1-5wt% of the total monomer content.

[0017] An application of the bifunctional polymer membrane is application of the bifunctional polymer membrane in preparing a potentiometric sensor.

[0018] A potential type sensor comprises the bifunctional polymer membrane.

[0019] The bifunctional polymer membrane is adhered to the bottom of the electrode matrix; the electrode is a solid contact polymer membrane ion selective electrode containing a conductive layer or a liquid contact polymer membrane ion selective electrode containing an internal filling liquid.

[0020] The potential type sensor is used in the detection of common cations in biological fluids to achieve low toxicity and anti-fouling.

[0021] The commonly detected ions are sodium ions, potassium ions, ammonium ions, calcium ions, lead ions, copper ions, iron ions, chromium ions or magnesium ions. The biological fluid is whole blood, serum, urine, sweat, tissue, intracellular fluid and dilutions thereof.

[0022] Detection principle: The present invention adopts a fluorinated polymer grafted with an ion carrier as the electrode sensitive membrane matrix, disperses the ion exchanger in the fluorinated methacrylate polymer matrix, and constructs a polymer membrane ion selective electrode with good stability and excellent biocompatibility (anti-fouling, low toxicity).

[0023] The advantages of the present invention are: The fluorine-based sensing membrane ion selective electrode constructed by the method of the present invention avoids the problem of biological fouling faced by the traditional polymer membrane ion selective electrode sensitive membrane when used in biological fluids, and eliminates the problem of electrode performance degradation and toxicity to the object to be measured caused by the leakage of reagents from the traditional sensitive membrane, effectively improving the stability, service life and biocompatibility of the electrode. The present invention is of great significance for the application of polymer sensitive membrane-based potential sensors in biomedical equipment.

[0024] 1. The present invention adopts a fluorinated polymer grafted with an ion carrier as the electrode sensitive membrane matrix, disperses the ion exchanger in the fluorinated methacrylate polymer matrix to obtain a sensitive membrane, and constructs a dual-function polymer membrane potential sensor with both low toxicity and anti-fouling advantages.

[0025] 2. The polymer membrane potential sensor of the present invention exhibits anti-biological fouling capability through the low surface energy characteristics of the fluorine-based sensing membrane, and the absence of plasticizers in the membrane phase reduces the biotoxicity problem caused by component leakage. This strategy greatly improves the biocompatibility of the sensor.

[0026] 3. The present invention adopts covalent bonding reaction to graft ion carriers onto the fluorine-containing polymer sensitive membrane phase, which solves the incompatibility problem between the ion carriers in the sensitive membrane phase and the fluorine-based sensing membrane. This has an important role in promoting the application of fluorine-based sensing membranes in the fields of polymer membrane-based optical devices and electrochemical sensors.

[0027] 4. The sensitive film of the present invention can be used to establish polymer film optical and electrochemical sensors with good stability and high biocompatibility, which will further promote the application and development of polymer film-based optical and electrochemical sensors in clinical testing, disease diagnosis, especially in implantable and wearable devices.

[0028] 5. The dual-function polymer membrane potential sensor of the present invention has good universality, and a variety of ion selective sensors can be constructed by changing the type of ion carrier. Therefore, the sensitive membrane of the present invention has good application prospects in the field of sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A technical roadmap for the synthesis of graftable calcium ion carriers provided in the embodiments of the present invention.

[0030] Figure 2 Graftable calcium ion carrier provided by the embodiment of the present invention 1 HNMR spectrum.

[0031] Figure 3 Schematic diagram of the synthesis of the fluorinated methacrylate polymer as a grafted ion carrier provided in an embodiment of the present invention.

[0032] Figure 4 The polymer membrane ion selective electrode provided in the embodiment of the present invention detects Ca 2+ Response diagram; wherein (A) is the bifunctional polymer membrane ion selective electrode electrode to Ca in Example 1 2+ Potential response calibration curve of (B) the ion selective electrode in Comparative Example 1 for Ca 2+ Potential response calibration curve.

[0033] Figure 5 A comparison chart of the toxicity of the dual-function electrode sensitive membrane provided in an embodiment of the present invention and the traditional PVC sensitive membrane containing plasticizers to cells; wherein a is a microscope image of the toxicity of the sensitive membrane obtained in an embodiment of the present invention to cell proliferation; b is a microscope image of the toxicity of the traditional sensitive membrane to cell proliferation.

[0034] Figure 6 Scanning electron microscope images of the conventional PVC sensitive membrane containing plasticizer (A, C) and the dual-function electrode sensitive membrane (B, D) provided in the embodiments of the present invention after being immersed in human whole blood for 12 hours. DETAILED DESCRIPTION

[0035] The specific implementation modes of the present invention are further described below in conjunction with examples. It should be noted that the specific implementation modes described here are only for illustrating and explaining the present invention, and are not limited to the present invention.

[0036] The dual-function polymer membrane potential sensor of the present invention is composed of a conventional disk electrode and a polymer sensitive membrane. The polymer sensitive membrane is prepared from a fluorinated methyl acrylate polymer grafted with an ion carrier and an ion exchanger. The surface of the sensitive membrane exhibits low surface energy characteristics, thereby showing good anti-biological fouling ability. In addition, since the membrane phase does not contain a plasticizer, the biological toxicity is low during long-term use. These two characteristics make it extremely advantageous in the biomedical field and are of great significance for further promoting the application and development of polymer membrane potential sensors in this field.

[0037] The bifunctional polymer membrane potential sensor of the present invention has both low toxicity and anti-fouling advantages. By changing the type of ion carrier, a variety of ion selective sensors can be constructed, and it has good universality. Therefore, the sensitive membrane of the present invention has good application prospects in the field of sensors. The sensor of the present invention has the advantages of simple preparation, excellent anti-biological fouling performance and low toxicity, which solves the biocompatibility problem faced by polymer membrane potential sensors in the biomedical field, especially in the field of wearable and implantable online monitoring equipment that has attracted much attention at present, during long-term application. This has important reference significance for the development of medical and health management equipment. Example 1

[0038] Taking the detection of calcium ions as an example, the specific preparation steps of the dual-functional polymer membrane potential sensor with both low toxicity and anti-fouling advantages are as follows: a. Polymerizable calcium ion carriers containing vinyl functional groups: Synthesis technology routes such as Figure 1 As shown. The specific steps are as follows: 5.48g of compound 1 (N-tert-butyloxycarbonyl-4-piperidone) was dissolved in methanol (200mL), 12.6g of sodium cyanoborohydride was added, and the mixture was stirred at 20°C for 3 hours. After the reaction was completed, water was added to quench the mixture and the mixture was extracted with dichloromethane. The organic phase was washed with water, dried over anhydrous sodium sulfate, and concentrated. The crude product was purified by silica gel column chromatography (dichloromethane / methanol, 1 / 0 to 20 / 1) to obtain 15.6g of compound 2. 13.1g of compound 5 (dicyclohexylamine) was dissolved in dichloromethane (220mL), 9.20g of diquinic anhydride was added, the mixture was stirred at 40°C for 5 hours, and 21.2g of compound 6 was obtained by concentration. 11.3 g of compound 6, 11.4 g of compound 2 and 9.85 g of DIEA (N,N-diisopropylethylamine) were dissolved in DMF (N,N-dimethylformamide, 120 mL), 21.7 g of HATU was added, and the mixture was stirred at 20°C for 2 hours, concentrated, and purified by reverse phase HPLC (0.1% formic acid) to obtain 6.30 g of compound 3. 6.10 g of compound 3 was dissolved in dichloromethane (36 mL), 4 M hydrochloric acid-dioxane solution (36 mL) was added, and the mixture was stirred at 25°C for 2 hours, and concentrated to obtain 7.30 g of compound 4 (hydrochloride). 7.30 g of compound 4 was dissolved in dichloromethane (70 mL), and 3.71 g of triethylamine and 1.46 g of acryloyl chloride were added in sequence at 0 ° C. The mixture was stirred at 25 ° C for 1 hour. After concentration, it was purified by preparative HPLC (Phenomenex Luna C18, [water (containing HCl)-acetonitrile], B%: 60%-90%, 20 minutes) to obtain a polymerizable calcium ion carrier. The final product was successfully synthesized by nuclear magnetic resonance ( Figure 2 ). 1HNMR (400 MHz, DMSO): δ6.80 (br dd, J = 10.4, 16.4 Hz, 1H), 6.09 (br d, J = 16.4 Hz, 1H), 5.66 (brd, J = 10.4 Hz, 1H), 4.63-4.33 (m, 1H), 4.10 (br d, J = 9.2 Hz, 5H), 3.48 (brs, 2H), 3.15-3.02 (m, 1H), 3.01-2.87 (m, 1H), 2.72-2.53 (m, 2H), 2.40-2.20(m, 3H), 1.85-1.47 (m, 16H), 1.47-1.14 (m, 12H), 1.07 (br d, J = 10.4 Hz, 3H).

[0039] b. Synthesis of fluorinated methacrylate polymer grafted with calcium ion carrier: Select tridecafluorooctyl methacrylate, lauryl methacrylate and the polymerizable calcium ion carrier containing vinyl functional groups obtained above, and synthesize copolymers by free radical polymerization. The synthesis process is as follows: Figure 3 As shown. Methacrylate tridecafluorooctyl ester and methacrylate lauryl ester were mixed in a mass ratio of 2:1 and added to a round-bottom flask, followed by the addition of initiator AIBN (1wt%) and a polymerizable calcium ion carrier containing a vinyl functional group (accounting for 5wt% of the total weight of the monomer). The mixture was dissolved in 10mL of benzene, ultrasonically treated for 15 minutes to ensure uniform dispersion, and then nitrogen was introduced for 15 minutes to remove oxygen from the solution. The reaction flask was placed in an 80°C oil bath for constant temperature polymerization for 16 hours. After the polymerization was completed, 10 times the volume of methanol was added to the polymer solution, and the copolymer was precipitated by vigorous stirring. The precipitate was redissolved in dioxane and then precipitated again in a large amount of ultrapure water, and repeated twice to remove unreacted monomers. Finally, the obtained white viscous copolymer was vacuum dried at room temperature for 24 hours to obtain the target product.

[0040] c. Preparation of calcium ion selective membrane solution: 98.0 mg of the above-mentioned fluorinated methyl acrylate polymer grafted with calcium ion carrier and 2.0 mg of ion exchanger sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaTFPB) were dissolved in 1 mL of dichloromethane and magnetically stirred for 24 h to disperse them evenly, thereby obtaining an electrode sensitive membrane solution.

[0041] d. Pretreatment process of disk electrode: Taking glassy carbon disk electrode as an example, the polished disk electrode is ultrasonically cleaned with anhydrous ethanol and deionized water, and the electrode surface is blown dry with nitrogen. The glassy carbon disk electrode is used as the working electrode, the Ag / AgCl electrode is used as the reference electrode, and the platinum wire electrode is used as the counter electrode. The electrodes are immersed in 0.1M poly (sodium 4-styrene sulfonate) (NaPSS) and 0.01M 3,4-ethylenedioxythiophene (EDOT) solution. After electrodeposition at a constant current of 0.01414mA for 714s, a uniform and dense PEDOT (PSS) film is formed on the surface of the working electrode. This modified layer can effectively avoid the influence of the water layer on the electrode performance.

[0042] e. Preparation of a dual-function polymer membrane potential sensor with low toxicity and anti-fouling advantages: After the disk electrode with the PEDOT (PSS) conductive layer deposited on the surface is cleaned and dried at room temperature, 100 μL of the electrode sensitive membrane solution obtained in step b is dripped onto the glassy carbon electrode with the PEDOT-PSS transduction layer deposited. The electrode with the calcium ion selective sensitive membrane dripped on is placed in a constant temperature and humidity chamber and dried for 12 hours. -3 The electrode to be tested was obtained after being activated in M ​​CaCl2 solution overnight. Comparative Example 1

[0043] Taking the detection of calcium ions as an example, the specific preparation steps of constructing a potentiometric sensor using fluorinated polymers and free active components are as follows: a. Synthesis of fluorinated methacrylate polymers: Tridecafluorooctyl methacrylate and lauryl methacrylate were mixed in a mass ratio of 2:1 and added to a round-bottom flask. Then, initiator AIBN (1wt%) was added to the round-bottom flask. After mixing, the mixture was dissolved in 10mL of benzene and ultrasonicated for 15min to keep the mixture uniform. Nitrogen was passed into the resulting mixed solution for 15min to remove oxygen from the mixed solution. Finally, the reaction bottle was placed in an 80°C oil bath for constant temperature polymerization for 16h. After the polymerization was completed, 10 times the volume of methanol was added to the polymer solution, and the copolymer was precipitated by vigorous stirring. The precipitate was redissolved in dioxane, and then precipitated again in a large amount of ultrapure water, and repeated twice to remove unreacted monomers. Finally, the obtained white viscous copolymer was vacuum dried at room temperature for 24 hours to obtain the target product.

[0044] b. Preparation of calcium ion selective membrane solution: 2.7 mg of the above-obtained polymerizable calcium ion carrier containing vinyl functional groups, 2.2 mg of ion exchanger sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaTFPB) and 95.1 mg of the above-obtained fluorinated methyl acrylate polymer were dissolved in 1 mL of dichloromethane and magnetically stirred for 24 h to uniformly disperse them to obtain an electrode sensitive membrane solution.

[0045] c. The deposition of the transduction layer, electrode preparation and activation process are the same as in Example 1. Application Example 1

[0046] Taking the detection of calcium ions as an example, the potential detection of calcium ions by the sensor is obtained using the above-mentioned Example 1 and Comparative Example 1: a. The calcium ion selective electrodes prepared in Example 1 and Comparative Example 1 were used as working electrodes and the Ag / AgCl electrode was used as the reference electrode to perform potential detection on calcium ions of different concentrations.

[0047] b. Use 1M calcium ion stock solution (containing 0.01M NaCl) prepared with CaCl2 and NaCl, and add calcium ion stock solution to 0.01M NaCl base solution to make the calcium ion in the base solution 10 -8 , 10 -7 , 10 -6 , 10 -5 , 10 -4 , 10 -3 , 10 -2 M, and then use the above-mentioned sensor to detect and record the potential values ​​generated by different concentrations of calcium ions.

[0048] c. After calibration of calcium ion concentration, the experimental results of the sensor constructed in Example 1 and Comparative Example 1 are shown in Figure 4 ,Depend on Figure 4 As shown in (A), the detection sensitivity of the electrode in Example 1 is 28.8 mV dec. -1 , which is close to the theoretical sensitivity calculated according to the Nernst equation, indicating that the constructed electrode has good detection performance for calcium ions of different concentrations. Figure 4 In (B), the electrode response is poor (does not conform to the Nernst response, has low sensitivity, and a narrow linear range), indicating that the configured sensitive membrane cannot meet the conditions for being a sensing element. Application Example 2

[0049] Taking the detection of calcium ions as an example, the calcium ion selective membrane prepared in Example 1 was used to conduct cytotoxicity studies: a. Cytotoxicity test was evaluated using L929 mouse fibroblast cell line as model cells.

[0050] The cells were cultured in RPMI 1640 medium supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin mixed solution and incubated at 37°C in an incubator under a 5% carbon dioxide atmosphere. All steps were performed under sterile conditions to prevent the cells from being contaminated by microorganisms.

[0051] b. 100 μl of the prepared calcium ion selective membrane solution was titrated to the bottom of a sterile culture dish and left to dry for 24 hours. Then, the culture dish containing the membrane was sterilized under ultraviolet light for 30 minutes, and then the calcium ion selective membrane was placed in a 96-well plate and immersed in the cell culture medium in step a for up to 10 days to allow the toxic substances in the membrane phase to penetrate into the cell culture medium. 100 μl of the extract was added to a 1.5×10 4 cells / well in a 96-well plate. To ensure the robust viability of the cells, the cells were first allowed to recover for about 2-3 days, then trypsinized and the trypsin was removed by centrifugation. After 48 hours of incubation, the cells were observed using an inverted fluorescence microscope (Revolve FL, Echo Laboratories, USA).

[0052] c. At the same time, a conventional polymer membrane calcium ion selective electrode sensitive membrane based on PVC and plasticizer o-nitrophenyl octyl ether with the same ion carrier and ion exchanger content was used as a comparative example to conduct parallel experiments under the same experimental conditions as above. The toxicity of the two sensitive membranes to cells was compared. Figure 5 .

[0053] Preparation of comparative polymer membrane: A mixture of 100 mg of PVC particles, o-nitrophenyl octyl ether, calcium ion carrier and sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, including 31.8wt% PVC particles, 63.7wt% o-nitrophenyl octyl ether, 2.3wt% calcium ion carrier and 2.2wt% sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, was transferred into 1 mL of tetrahydrofuran solution and stirred for 24 hours to make it evenly dispersed, thereby obtaining a traditional PVC-based sensitive membrane solution.

[0054] The exudate of the sensitive membrane based on PVC and plasticizer o-nitrophenyl octyl ether was incubated ( Figure 5 The number of cells in b) is much lower than that in ( Figure 5 a) The number of cells in the experiment. In addition, the cell morphology also underwent certain shrinkage changes. These results show that the exudation of plasticizers in the conventional sensitive membrane phase has certain toxicity to the cell division and proliferation, thus affecting its growth. Therefore, it can be proved that the polymer membrane ion selective electrode sensitive membrane proposed in Example 1 has low biological toxicity. Application Example 3

[0055] Taking the detection of calcium ions as an example, the polymer sensitive membrane prepared in Example 1 was immersed in a human whole blood sample for 24 hours to observe the protein and cell adsorption on the membrane surface: a. Pour the calcium ion selective membrane solution obtained in step b of Example 1 into a glass ring (inner diameter 3.6 cm) fixed on a glass plate and place it in a room temperature and low humidity environment for 12 hours to obtain a uniform polymer calcium ion sensitive membrane. Use a punch to obtain a disc-shaped transparent film for experiment.

[0056] b. The sensitive membrane was exposed to the whole blood sample for 12 hours at room temperature, and then rinsed with phosphate buffered saline (PBS) to remove unadsorbed cells and proteins. After that, the membrane was fixed in a PBS solution containing 2.0% (w / v) glutaraldehyde for 2 hours to fix the cells (platelets, blood cells, etc.) adsorbed on the membrane surface, and then the membrane was immersed in a series of diluted ethanol solutions (30, 50, 70, 90, 95, 100% v / v) for dehydration. After the solvent evaporated overnight, the membrane surface was sprayed with gold and observed using a scanning electron microscope (SEM).

[0057] c. At the same time, a conventional polymer membrane calcium ion selective electrode sensitive membrane based on PVC and plasticizer o-nitrophenyl octyl ether with the same ion carrier and ion exchanger content was used as a comparative example. The scanning electron microscopy of the two sensitive membranes after incubation with blood samples was as follows: Figure 6 .

[0058] Depend on Figure 6 As shown in (A) and (C), after the traditional electrode sensitive membrane was incubated with blood samples, a large number of cells were adsorbed on the electrode surface, and even thrombosis occurred. However, only a small number of cells were adsorbed on the electrode sensitive membrane proposed in the present invention ( Figure 6 The above results show that the sensor of the present invention has the advantages of low toxicity and anti-fouling, and has good anti-cell adhesion function, and has the potential for long-term application in biological fluids. Example 2

[0059] Taking the detection of potassium ions as an example, the specific preparation steps of the potentiometric sensor are as follows: a. Synthesis of fluorinated methacrylate polymer grafted with potassium ion carrier: methacrylate tridecafluorooctyl ester and methacrylate lauryl ester were mixed in a mass ratio of 2:1 and added to a round-bottom flask, and then initiator AIBN (1wt%) and polymerizable potassium ion carrier (specifically 4-acryloylamidobenzo-15-crown-5 or 4-acryloylamidobenzo-18-crown-6, 1wt% of the monomer mass) were added to the round-bottom flask. After mixing, the mixture was dissolved in 10mL of benzene and ultrasonicated for 5min to keep the mixture uniform. Nitrogen was passed into the obtained mixed solution for 15min to remove oxygen in the mixed solution. Finally, the reaction bottle was placed in an oil bath pot at 80℃ for constant temperature polymerization for 16h. After the polymerization was completed, 10 times the volume of methanol was added to the polymer solution, and the copolymer was precipitated by vigorous stirring. The precipitate was redissolved in dioxane and then precipitated again in a large amount of ultrapure water, and the process was repeated twice to remove the unreacted monomers. Finally, the obtained white viscous copolymer was dried under vacuum at room temperature for 24 hours to obtain the target product.

[0060] b. Preparation of potassium ion selective membrane solution: 99.4 mg of the above-mentioned fluorinated methyl acrylate polymer grafted with potassium ion carrier and 0.6 mg of ion exchanger sodium tetrakis(3,5-di(trifluoromethyl)phenyl)borate (NaTFPB) were dissolved in 1 mL of dichloromethane and magnetically stirred for 24 h to disperse them evenly, thereby obtaining an electrode sensitive membrane solution.

[0061] c. Pretreatment process of disk electrode: Taking magnetic glassy carbon disk electrode as an example, the polished disk electrode is ultrasonically cleaned with anhydrous ethanol and deionized water, and the electrode surface is blown dry with nitrogen. The magnetic glassy carbon disk electrode is used as the working electrode, the Ag / AgCl electrode is used as the reference electrode, and the platinum wire electrode is used as the counter electrode. The electrodes are immersed in 0.1M poly (sodium 4-styrene sulfonate) (NaPSS) and 0.01M 3,4-ethylenedioxythiophene (EDOT) solution. After electrodeposition at a constant current of 0.01414mA for 714s, a uniform and dense PEDOT (PSS) film is formed on the surface of the working electrode. This modified layer can effectively avoid the influence of the water layer on the electrode performance.

[0062] d. Preparation of potassium ion selective electrode: After the disk electrode with PEDOT (PSS) conductive layer deposited on the surface was washed and dried at room temperature, 100 μL of the potassium ion selective membrane solution obtained above was modified on its surface by drop coating, and then the modified disk electrode was placed in a constant temperature drying oven to dry overnight for use. -3 The samples were activated in MKCl solution overnight.

[0063] At the same time, different ion selective carriers (such as sodium ion carriers, magnesium ion carriers, ammonium ion carriers, copper ion carriers, etc.) are added during the preparation process of the ion selective sensitive membrane described in Example 1 or Example 2, and different bifunctional polymer membrane potential sensors can be constructed, which shows the universality of this method.

[0064] In summary, the novel fluorine-based sensing membrane ion selective electrode constructed by the method of the present invention avoids the problem of biological fouling faced by the traditional polymer membrane ion selective electrode sensitive membrane when used in biological fluids, and eliminates the problem of electrode performance degradation and toxicity to the object to be measured caused by the leakage of reagents from the traditional sensitive membrane, effectively improving the stability, service life and biocompatibility of the electrode. The present invention is of great significance for the application of polymer sensitive membrane-based potential sensors in biomedical equipment.

Claims

1. A bifunctional polymer film, characterized in that: The bifunctional polymer membrane comprises, by weight, 0.05-10 parts of an ion exchanger and 10-90 parts of a sensitive membrane matrix of a grafted ion carrier; wherein the sensitive membrane matrix of the grafted ion carrier is a fluorine-containing methacrylate polymer of the grafted ion carrier; the fluorine-containing methacrylate polymer of the grafted ion carrier is obtained by free radical polymerization of a fluorine-containing methacrylate monomer, a monomer with a low glass transition temperature and a polymerizable ion carrier, or is obtained by reacting a fluorine-containing methacrylate monomer with a low glass transition temperature with a polymerizable ion carrier; wherein the monomer with a low glass transition temperature is a methacrylate or acrylate monomer with a low glass transition temperature.

2. The bifunctional polymer membrane according to claim 1, characterized in that: The fluorine-containing methacrylate monomer and the monomer having a low glass transition temperature are mixed in a molar ratio of 1-50:10-80.

3. The bifunctional polymer membrane according to claim 1, characterized in that: The bifunctional polymer membrane is a mixture of a sensitive membrane matrix grafted with an ion carrier and an ion exchanger, which is fully dissolved in a non-polar organic solvent and evaporated naturally at room temperature.

4. The bifunctional polymer membrane according to claim 1, characterized in that: The ion exchanger is one or more fluorine-containing ion exchangers.

5. The bifunctional polymer membrane according to claim 1, characterized in that: The sensitive membrane matrix of the grafted ion carrier is prepared by mixing a fluorine-containing methyl acrylate monomer and a monomer with a low glass transition temperature, or a fluorine-containing methyl acrylate monomer with a low glass transition temperature with a covalently linked ion carrier in an organic solvent, stirring evenly, adding an initiator, and thermally initiating polymerization at 60-90° C. for 8-24 hours to obtain a transparent solution; dropping the transparent solution into a cold polar organic solvent to form a gel-like precipitate; dissolving the obtained copolymer precipitate in dioxane, then precipitating the precipitate with ultrapure water, and vacuum drying the obtained white viscous copolymer at room temperature for 12-48 hours to obtain the target product.

6. The bifunctional polymer membrane according to claim 5, characterized in that: The covalently linked ionophore is a polymerizable ionophore containing a vinyl functional group; The added amount accounts for 0.5-20wt% of the total mass percentage of the polymerization reaction monomers.

7. The bifunctional polymer membrane according to claim 1, characterized in that: The fluorine-containing methacrylate monomer is dodecafluoroheptyl methacrylate and / or tridecafluorooctyl methacrylate; the low glass transition temperature monomer is n-butyl acrylate, lauryl methacrylate, isodecyl acrylate, n-decyl methacrylate and / or isooctyl acrylate.

8. An application of the bifunctional polymer membrane according to claim 1, characterized in that: Application of the bifunctional polymer film in preparing a potential-type sensor.

9. A potential type sensor, characterized in that: A bifunctional polymer film comprising the bifunctional polymer film according to claim 1.

10. The potential type sensor according to claim 9, characterized in that: The bifunctional polymer membrane described in claim 1 is adhered to the bottom of the electrode substrate; the electrode is a solid contact polymer membrane ion selective electrode containing a conductive layer or a liquid contact polymer membrane ion selective electrode containing an internal filling liquid.

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