An updatable polymer membrane potential type anti-fouling sensor and its application

Abstract

The present invention relates to a potentiometric anti-biofouling sensor, specifically to a renewable polymer membrane potentiometric anti-biofouling sensor modified with a magnetic anti-fouling functional material and its application. The polymer membrane potentiometric anti-biofouling sensor is composed of a disk electrode, a polymer sensitive membrane, and a magnetic material anti-fouling layer; the polymer membrane is coated on the surface of the conductive substrate of the disk electrode, and a magnetic material anti-fouling layer is self-assembled on the surface of the polymer membrane through the action of magnetic field force; among them, the disk electrode has magnetism. The renewable potentiometric anti-biofouling sensor modified with a magnetic anti-fouling functional material according to the present invention realizes the hindrance to biological attachment and biofilm formation by means of a magnetic anti-fouling functional material with super-hydrophilicity and bactericidal properties, and at the same time improves the anti-biofouling performance of the polymer membrane potentiometric sensor by virtue of the advantage that the magnetic anti-fouling layer is easy to update.

Description

Technical Field

[0001] The present invention relates to a potentiometric anti-biofouling sensor, and more particularly to a renewable polymer membrane potentiometric anti-biofouling sensor modified with a magnetic anti-fouling functional material and its application. Background Art

[0002] Ion-selective electrodes, as a common type of electrochemical sensor, have the characteristics of simple operation, low cost, low energy consumption, and excellent detection performance. Potentiometric sensors based on polymer membrane ion-selective electrodes have been widely used in environmental monitoring, clinical diagnosis, food detection, biosensing and other fields. Especially in environmental monitoring, polymer membrane ion-selective electrodes play an important role in the real-time and accurate analysis of some environmental parameters such as pH, Ca 2+ concentration, CO3 2- concentration, nutrients, etc. However, ion-selective electrodes are difficult to be applied in complex environmental matrices for a long time. This is mainly because a variety of complex components (such as organic substances or microorganisms) will adsorb on the surface of the polymer sensitive membrane of the sensor, causing biofouling on the sensor surface, affecting the thermodynamic and kinetic responses of the electrode, and thus affecting the stability and accuracy of long-term monitoring of the sensor.

[0003] To reduce the influence of biofouling in environmental water bodies on polymer membrane sensors, several methods have been proposed by researchers to improve the anti-biofouling ability of polymer membrane potentiometric sensors, which are mainly divided into two categories: one is to modify the anti-fouling material on the surface of the polymer membrane, but this method has a cumbersome and complex operation process and limited anti-fouling performance, and the common chemical modification methods for functionalizing the electrode surface are likely to damage the polymer membrane and thus affect its performance; the other is to dope antibacterial active ingredients during the membrane fabrication process to construct an anti-fouling polymer membrane, and such methods have problems such as limited adhesion to microorganisms or organic substances. Therefore, it is still a major problem to develop a simple, stable and excellent anti-biofouling polymer membrane potentiometric sensor without affecting the detection performance. In addition, there is currently no method that can achieve complete anti-fouling, and most methods improve the anti-fouling ability of the electrode by delaying the occurrence of fouling. As the working time of the sensor in complex environmental matrices extends, the anti-fouling efficacy of the sensor gradually decreases, and dead and live bacteria gradually accumulate and adhere on the surface of the sensor and eventually lead to the occurrence of biofouling. In the current research on anti-fouling of polymer membrane ion-selective electrodes, most of the research focuses on how to improve the anti-biofouling ability of ion-selective electrodes in complex environmental matrices, and has not involved how to restore the anti-bioadhesion performance of fouled anti-fouling electrodes. Realizing the renewal of the anti-fouling functional layer on the polymer membrane surface is crucial for improving the sustainable anti-biofouling ability of polymer membrane potentiometric sensors. Summary of the Invention

[0004] The object of the present invention is to provide a renewable polymer membrane potentiometric antifouling sensor modified with a magnetic antifouling functional material and its application.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A renewable polymer membrane potentiometric antifouling sensor, which is composed of a disk electrode, a polymer sensitive membrane, and a magnetic material antifouling layer; the polymer membrane is coated on the surface of the conductive substrate of the disk electrode, and a magnetic material antifouling layer is self-assembled on the surface of the polymer membrane through the action of magnetic force; wherein, the disk electrode has magnetism.

[0007] The magnetic material antifouling layer is based on Fe3O4, and a hydrophilic material (hydrophilicity and steric hindrance effect) and a cationic polymer (antibacterial property) are loaded on its surface to form a composite magnetic material with a dual antifouling function.

[0008] The composite magnetic material with the dual antifouling function can achieve antifouling against bacterial adhesion by utilizing the superhydrophilicity of the material and antibacterial performance by utilizing the bactericidal property of the material.

[0009] The composite magnetic material with the dual antifouling function is prepared by placing the Fe3O4 synthesized by the kettle boiling method in a solution containing a hydrophilic material, so that a coating with a hydrophilic material is formed on the surface of Fe3O4, and then it is placed in an aqueous solution of a cationic polymer and stirred and mixed at 40-60 °C, and covalently bonded to the surface of the hydrophilic coating to form a composite magnetic material with a dual antifouling function.

[0010] The hydrophilic material is one or more of zwitterionic polymers (such as phosphocholine, betaine, etc.), nanomaterials (such as graphene oxide, titanium dioxide, etc.), polyethylene glycol and its derivatives, hydrogels (such as polyvinyl alcohol hydrogel, graphene-based hydrogel, etc.), polypeptide materials; the hydrophilic material can be dissolved / dispersed in solvents such as water, methanol, N,N-dimethylformamide, etc., and the hydrophilic modification of the substrate is realized through covalent bonds (such as amino-carboxamide reaction, dopamine self-polymerization reaction, and dopamine-assisted one-step co-deposition reaction, etc.) / non-covalent bonds (such as electrostatic interaction, hydrogen bond interaction, π-π stacking interaction, etc.).

[0011] The cationic polymer is one or more of quaternary ammonium salt polymers (such as acrylic acid and methacrylate polymers, polysiloxane quaternary ammonium salts, etc.), N-haloamine polymers (such as amino N-haloamines, amide N-haloamines, etc.), phosphonium salts (such as 2-trimethylphosphonium acetylchrysanthemum powder, poly[4-(2-tributyl-ethylphosphonium)styrene chloride-co-4-(2-ethyl chloride)styrene, etc.), sulfonium salt polymers (such as 4-vinylbenzyltetramethylene sulfonium tetrafluoroborate polymer, tris(n-alkyl)sulfonium salts, etc.), guanidine salt polymers (such as polycyclohexane biguanide, polycyclohexane guanidine, etc.), and antibacterial hydrogels (such as β-sheet-type -peptide-based hydrogels, dextran aldehyde / polyethyleneimine hydrogels, etc.).

[0012] The composite magnetic material with dual antifouling function is prepared by placing Fe3O4 synthesized by the autoclave method in a solution containing dopamine (DA) and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt (SBMA), stirring and mixing evenly, so that a polydopamine (PDA)-poly(dimethylpropylsulfonic acid amide ethyl methacrylate) (PSBMA) coating Fe3O4@PDA-PSBMA is formed on the surface of Fe3O4. Then, Fe3O4@PDA-PSBMA is added to an aqueous solution of dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (QAC C18 ) and stirred at 40-60 °C for 6-8 hours, and covalently bonded to the surface of the hydrophilic coating to form a composite magnetic material Fe3O4@PDA-PSBMA@QAC with dual antifouling function C18 .

[0013] The solution containing dopamine (DA) and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt (SBMA) is prepared by dissolving dopamine and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt in Tris-HCl with a pH of 8.5 at a mass ratio of 1:15; wherein, the concentration of dopamine is 0.001-1000 mg / L; the mass ratio of Fe3O4 to dopamine powder is 0.5-1; the aqueous solution of dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (QAC C18 ) is prepared by mixing a commercial QAC C18 solution with deionized water and adjusting the pH to 3-4 with glacial acetic acid

[0014] The disk electrode is a magnetic glassy carbon disk electrode, a magnetic gold disk electrode or a magnetic platinum disk electrode

[0015] The surface of the disk electrode is coated with a polymer sensitive film, which is a solid-contact polymer membrane ion-selective electrode. An ion-electron conduction layer can be added to the conductive substrate surface of the disk electrode to improve the stability of the electrode response signal.

[0016] The polymer sensitive film is prepared by mixing an ion-selective carrier, a lipophilic ion exchanger, a membrane base material, and a plasticizer in a weight ratio of 0.2 - 10:0.1 - 5:20 - 40:40 - 80, then dissolving them in a tetrahydrofuran solution, and then dropping the solution onto the surface of the disk electrode and allowing it to evaporate naturally at room temperature.

[0017] The polymer membrane potential type anti-fouling sensor is prepared by inserting a conventional magnetic disk electrode with a polymer film coated on the bottom into an aqueous solution containing the magnetic anti-fouling material for 1 - 10 minutes, and then uniformly fixing the magnetic anti-fouling material on the surface of the electrode polymer film under the induction of magnetic force.

[0018] The polymer membrane electrode modified with the anti-fouling magnetic material is immersed in deionized water and subjected to an external opposite magnetic force for 10 - 30 minutes to remove the anti-fouling layer on the electrode surface, and then the replacement can be realized.

[0019] Application of the renewable polymer membrane potential type anti-fouling sensor, which is applied to the anti-biofouling in the detection of common cations in environmental water bodies by the polymer membrane potential type anti-fouling sensor.

[0020] The common ions to be detected are lead ions, copper ions, iron ions, chromium ions, sodium ions, potassium ions, ammonium ions, calcium ions, magnesium ions, carbonate ions, nitrate ions, chloride ions, or bromide ions. The environmental water body is lake water, river water, or seawater.

[0021] Principle of action: Traditional polymer membrane sensors are difficult to be applied in complex environmental matrices for a long time because various complex components in seawater (such as organic substances or microorganisms) will adsorb on the surface of the sensor polymer sensitive film, causing biofouling on the sensor surface, thereby affecting the stability and accuracy of long-term monitoring of the sensor. The present invention utilizes the magnetism of Fe3O4, the hydrophilicity and steric hindrance of zwitterionic (poly[2-(methacryloyloxy)ethyl dimethyl-(3-sulfopropyl) ammonium hydroxide], PSBMA) materials, and the quaternary ammonium salt cationic polymer (dimethyl octadecyl [3-trimethoxysilylpropyl] ammonium chloride, QAC C18A composite material is obtained, which has dual properties of preventing bacterial adhesion and sterilization, thereby enabling it to have good anti-biofouling effect. Then, a binary composite anti-fouling active material with anti-adhesion and sterilization functions is combined with a polymer membrane potentiometric sensor, and at the same time, a magnetic field-induced self-assembly technology is adopted to realize the self-assembly and immobilization of the anti-fouling material on the sensor surface, effectively improving the anti-fouling performance of the polymer membrane sensor in a complex environment. At the same time, with the help of the magnetic induction technology, the simple update of the anti-fouling functional layer on the sensor surface can be realized, further improving the sustainability of the anti-fouling efficacy of the polymer membrane sensor. In addition, the sensor can generate a potential response to the ion to be measured, realizing the detection of common ions in environmental water bodies.

[0022] The advantages of the present invention are as follows:

[0023] 1. The present invention is based on a renewable polymer membrane potentiometric anti-fouling sensor modified with a magnetic anti-fouling functional material. For the first time, a dual-functional (anti-adhesion, antibacterial) composite anti-fouling magnetic material is modified on the surface of the polymer membrane potentiometric sensor to improve the anti-biofouling activity of the potentiometric sensor in the environment, and the response performance of the electrode can be better maintained in a high-concentration fouling environment.

[0024] 2. For the polymer membrane potentiometric anti-fouling sensor of the present invention, an anti-fouling layer is self-assembled on the surface of the polymer ion-selective electrode through the action of magnetic force. This modification method is not only simple in operation but also can avoid the damage to the polymer membrane during the chemical modification process.

[0025] 3. The polymer membrane potentiometric anti-biofouling sensor of the present invention makes the anti-fouling layer easy to update by using paramagnetism and diamagnetism, and can realize the long-term, highly efficient and stable anti-fouling of the sensor.

[0026] 4. In the polymer membrane potentiometric anti-fouling sensor of the present invention, the anti-fouling layer combines the high hydrophilicity and bactericidal characteristics of the material, and the sensor has excellent anti-fouling performance. At the same time, the construction of the anti-fouling layer has a certain universality for the polymer membrane potentiometric sensor, and various ion-selective anti-fouling sensors can be constructed by changing the types of ion carriers.

[0027] 5. The polymer membrane potentiometric anti-fouling sensor of the present invention can be applied to the low detection limit detection of various environmental water bodies or high-concentration bacterial solution environments. At the same time, after the anti-fouling functional layer is fouled, it can be simply updated, and the detection limit of the electrode is not significantly affected after the update. Therefore, the present invention will play a huge role in the fields of water quality analysis, environmental monitoring, pollutant control, etc. Brief Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the synthesis of a magnetic anti-fouling functional material and the corresponding scanning electron microscope image provided for Embodiment 1 of the present invention.

[0029] Figure 2Schematic diagram of the renewable polymer membrane potentiometric anti-fouling sensor modified with magnetic anti-fouling functional materials provided in Embodiment 1 of the present invention.

[0030] Figure 3 Potential response diagram of the renewable polymer membrane potentiometric anti-fouling sensor provided in Embodiment 1 of the present invention for measuring different concentrations of Ca in 0.5M NaCl solution 2+ of.

[0031] Figure 4 Plate map of bacteria after overnight culture of seawater bacteria in Embodiment 3 of the present invention, stimulated for two hours, and then diluted 100 times.

[0032] Figure 5 Potential response diagram (A - before update; B - after update) of the renewable polymer membrane potentiometric anti-fouling sensor provided in Embodiment 1 of the present invention for measuring different concentrations of Ca in 0.5M NaCl solution after continuous immersion in high-concentration bacterial solution for 10 days. 2+ of.

[0033] Figure 6 Colony coverage rate on the surface of the sensitive membrane of the polymer membrane potentiometric anti-fouling sensor provided in Embodiment 1 of the present invention after immersion in bacterial solution for 5 hours. Specific Embodiments

[0034] The following further illustrates the specific embodiments of the present invention in combination with examples. It should be noted that the specific embodiments described here are only for explaining and interpreting the present invention and are not limited to the present invention.

[0035] The polymer membrane potentiometric anti-fouling sensor of the present invention is composed of a conventional magnetic disk electrode, a polymer sensitive membrane, and a magnetic material anti-fouling layer. The conductive substrate surface of the conventional magnetic disk electrode is coated with a polymer membrane, and then, through the action of magnetic field force, an anti-fouling layer is self-assembled on the surface of the polymer membrane. This modification method is not only simple to operate but also can avoid damage to the polymer membrane during the chemical modification process, and has a certain universality for various polymer membrane potentiometric sensors. The renewable polymer membrane potentiometric anti-fouling sensor based on magnetic anti-fouling functional material modification of the present invention can achieve the anti-fouling performance of the polymer membrane potentiometric sensor by means of the hydrophilicity and steric hindrance effect of zwitterionic materials and the bactericidal effect of quaternary ammonium salt cationic polymers on microorganisms, thereby solving the biofouling problem often faced by polymer membrane potentiometric sensors in complex water bodies. At the same time, the present invention can achieve simple renewal of the anti-fouling functional layer on the sensor surface by means of magnetic induction technology, further improving the sustainability of the anti-fouling efficacy of the polymer membrane sensor. This anti-fouling sensor has the advantages of simple preparation, easy renewal of the anti-fouling layer, and excellent anti-fouling performance.

[0036] The anti-fouling sensor of the present invention is a renewable potentiometric anti-fouling sensor modified with a magnetic anti-fouling functional material. By means of the anti-fouling functional magnetic material with super-hydrophilicity and bactericidal properties, it realizes the hindrance effect on biological attachment and biofilm formation, and improves the anti-biofouling performance of the polymer film potentiometric sensor. In addition, after the renewable polymer film potentiometric anti-fouling sensor modified with the magnetic anti-fouling functional material is fouled during long-term use in environmental water bodies, the anti-fouling layer can be updated by virtue of the easy renewal advantage of the magnetic material, extending the service life of the anti-fouling sensor, and solving the problem that the anti-fouling efficacy of the anti-fouling functional layer of the polymer film potentiometric anti-fouling sensor gradually decreases or even fails with the extension of time during long-term application in complex water bodies, thereby realizing sustainable and efficient anti-fouling.

[0037] Example 1

[0038] Taking the detection of calcium ions as an example, the specific preparation steps of the renewable polymer film potentiometric anti-fouling sensor modified with the magnetic anti-fouling functional material are as follows:

[0039] a. Synthesis of the magnetic anti-fouling functional material: First, magnetic microspheres are synthesized by the autoclave method. Specifically, 1.35 g of FeCl3·6H2O is added to 40 mL of ethylene glycol solution, and a transparent solution is formed under magnetic stirring. Subsequently, 3.6 g of NaAc and 1.0 g of polyethylene glycol are added to the solution and stirred vigorously for 30 min. Finally, the formed solution is placed in a 100 mL reaction kettle and reacted at 200 °C for 8 hours to obtain a suspension of Fe3O4 magnetic microspheres. After cooling to room temperature, the obtained black product is washed by magnetic separation technology and vacuum dried at 60 °C for 24 hours to obtain a black dry powder (Fe3O4 magnetic microspheres). 200 mg of the synthesized Fe3O4 microspheres are dispersed in a 10 mM Tris-HCl solution with a pH of 8.5 containing 2 mg / L of dopamine and 30 mg / L of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt (SBMA) and mechanically stirred for 8 hours to form a polydopamine (PDA)-poly(dimethylpropylsulfonic acid amide ethyl acrylate) (PSBMA) coating on the surface of the Fe3O4 microspheres. Then, the Fe3O4@PDA-PSBMA microspheres are added to an aqueous solution of dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (QAC C18 ) (15 mL of commercial QAC C18 solution plus 35 mL of deionized water, and the pH is adjusted to 3.5 with glacial acetic acid), and mechanically stirred at 60 °C for 6 hours to form a composite magnetic material Fe3O4@PDA-PSBMA@QAC with dual anti-fouling functions C18 . The obtained black product is collected by magnetic separation technology and placed in a vacuum drying oven for vacuum drying at 60 °C for 24 hours to obtain Fe3O4@PDA-PSBMA@QAC C18Microsphere-magnetic antifouling functional material (see the synthesis process and corresponding scanning electron micrographs in Figure 1 ).

[0040] b. Preparation of calcium ion selective membrane solution: A mixture of 360 mg of PVC particles, o-nitrophenyl octyl ether, calcium ionophore, and sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, where 31.8 wt% is PVC particles, 63.7 wt% is o-nitrophenyl octyl ether, 2.3 wt% is calcium ionophore, and 2.2 wt% is sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, is transferred into 3.6 mL of tetrahydrofuran solution and stirred for 6 h to disperse evenly, obtaining the electrode sensitive membrane solution.

[0041] c. Pretreatment process of the disk electrode: Taking the magnetic glassy carbon disk electrode as an example, after the polished disk electrode is ultrasonically cleaned with absolute ethanol and deionized water, the electrode surface is dried with nitrogen. Using the magnetic glassy carbon disk electrode as the working electrode, the Ag / AgCl electrode as the reference electrode, and the platinum wire electrode as the counter electrode, the electrodes are immersed in a solution of 0.1 M poly(4-styrenesulfonate) (NaPSS) and 0.01 M 3,4-ethylenedioxythiophene (EDOT). After electrodeposition at a constant current of 0.01414 mA for 714 s, 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] d. Preparation of a renewable polymer membrane potentiometric antifouling sensor modified with magnetic antifouling functional material: After the disk electrode with the PEDOT(PSS) conduction layer deposited on its surface is cleaned and dried at room temperature, 100 μL of the above-obtained polymer calcium ion selective membrane solution is modified on its surface by the drop-coating method, and then the modified disk electrode is placed in a constant temperature drying oven and dried overnight for standby. The above-obtained calcium ion selective electrode is placed in 10 -3 M CaCl2 solution and activated overnight. The activated polymer membrane calcium ion selective electrode is vertically placed in 1 mL of Fe3O4@PDA-PSBMA@QAC C18 solution (0.3 mg / mL) for 10 min, and the magnetic antifouling functional material is adsorbed on the electrode surface by the magnetic induction force of the magnetic core inside the electrode to form an antifouling layer, obtaining a renewable potentiometric antifouling sensor (see Figure 2 ).

[0043] Example 2

[0044] Taking the detection of calcium ions as an example, the potential detection of calcium ions by the sensor obtained in the above example is as follows:

[0045] a. Using the anti-fouling calcium ion selective electrode prepared in Example 1 as the working electrode and the Ag / AgCl electrode as the reference electrode, the potential of calcium ions at different concentrations was detected;

[0046] b. The obtained anti-fouling calcium ion selective electrode was placed in 10 -3 M CaCl2 solution for 1 h of activation. Using a 1 M calcium ion stock solution (containing 0.5 M NaCl) prepared with CaCl2 and NaCl, the calcium ion stock solution was added to the 0.5 M NaCl bottom solution to make the calcium ions in the bottom solution 10 -7 、10 -6 、10 -5 、10 -4 、10 -3 、10 -2 、10 -1 M. Then, the above-built sensor was used for detection, and the potential values generated by calcium ions at different concentrations were recorded (see Figure 3 ). After calibrating the calcium ion concentration, the experimental results are shown in Figure 3 . As can be seen from Figure 3 , the obtained detection sensitivity was 27.73 mV dec -1 , which was close to the theoretical sensitivity calculated according to the Nernst equation, indicating that the constructed electrode had good detection performance for calcium ions at different concentrations. At the same time, the electrode without the anti-fouling layer was used as a control.

[0047] Example 3

[0048] Taking the detection of calcium ions as an example, the potential response of the sensor obtained in Example 1 above to calcium ions after being immersed in a high-concentration bacterial solution for 10 days:

[0049] a. Cultivation and preparation of the high-concentration bacterial solution: Mix 1 mL of seawater with 9 mL of LB medium evenly and place it in a shaker at 37 °C for overnight cultivation. Then, take 1 mL of the overnight culture broth containing bacteria and mix it evenly with 9 mL of LB medium and place it in a shaker at 37 °C for 2 h. By centrifuging at 5000 r / min for 2 min, the bacteria were separated from the medium, and the bacteria were washed 3 times with sterile physiological saline. Then, the bacteria were dispersed in sterile physiological saline to obtain a bacterial suspension with a concentration of 10 8 or 10 9 CFU mL -1 for standby (the diluted seawater bacteria cultured and plated are shown in Figure 4 ).

[0050] b. Place the polymer membrane potential type anti-fouling sensor obtained in Example 1 in the bacterial suspension in step a) (10 8 CFU mL -1After being immersed in [] for 10 days, the antifouling sensor was taken out, washed with physiological saline, and then placed in 10 -3 M CaCl2 solution for overnight activation. The potential of different calcium ion concentrations was detected, and the operation process was carried out according to step c of Example 2. After the calcium ion concentration was corrected, the experimental results are shown in Figure 5 A. At the same time, an electrode without a modified antifouling layer was used as a control.

[0051] c. The polymer membrane potential type antifouling sensor obtained in Example 1 for detecting different calcium ion concentrations was placed in the bacterial suspension (10 8 CFU mL -1 ) obtained in step a) above for 10 days. Then, after the electrode was washed with physiological saline, the internal magnetic core of the electrode was taken out and placed in 5 mL of deionized water. After applying an opposite magnetic field for 10 minutes, it was gently rinsed with deionized water to obtain an updated electrode. Then it was placed in 10 -3 M CaCl2 solution for overnight activation. The potential of different calcium ion concentrations was detected, and the operation process was carried out according to step c of Example 2. After the calcium ion concentration was corrected, the experimental results are shown in Figure 5 B.

[0052] From Figure 5 A, it can be seen that the performance of the constructed electrode was not affected in an environment containing a high concentration of fouling organisms, indicating that it has good resistance to the attachment of fouling organisms; from Figure 5 B, it can be seen that the response slope of the antifouling electrode was basically not affected after updating, and the response time was significantly shortened, proving the renewability of the antifouling electrode. According to the data obtained from the tests in Example 2 and 3, a calibration curve was made, and the detection limits of three different electrodes (unmodified electrode, modified electrode, updated electrode) were calculated as shown in Table 1. It can be seen from Table 1 that the antifouling electrode changed by about 0.5 orders of magnitude before and after fouling. Compared with the unmodified electrode (which changed by 1 order of magnitude), it proved that the antifouling electrode has good antifouling ability. Compared with the unmodified electrode before fouling, the detection limit of the updated electrode did not change significantly, proving that the antifouling layer of the updated antifouling electrode is relatively easy to update, and the performance of the electrode can be restored to near the initial state after updating. Continuous modification can achieve long-term, highly efficient and stable anti-fouling of the sensor.

[0053] Table 1

[0054]

[0055] Example 4

[0056] Taking the detection of calcium ions as an example, the polymer sensitive membrane prepared in Example 1 above was immersed in a high-concentration bacterial solution for 5 hours, and then the bacterial distribution on the membrane surface was observed:

[0057] 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 at room temperature for 8 h to obtain a uniform polymer calcium ion-sensitive membrane. Use a puncher to obtain a round transparent membrane with a diameter of 0.6 cm as a control. Drop 30 μL of Fe3O4@PDA-PSBMA@QAC C18 suspension (10 mg / mL) on the control membrane. After the deionized water has evaporated, an antifouling membrane is obtained.

[0058] b. After contacting the control membrane and the antifouling membrane obtained in the above step a with the bacterial suspension (10 9 CFU / mL -1 ) obtained in Example 3a for 5 h, wash the two membrane-sensitive membranes with normal saline to remove the unadsorbed bacteria, and then stain them with SYTO 9 (3.34 μM) and PI (20 μM) in the dark for 30 min. After staining, gently rinse with deionized water and place them under a laser confocal scanning microscope to observe the quantity and state of the bacteria adsorbed on the membrane surface. Then, based on the laser confocal scanning microscope photos, perform a coverage rate statistics on the colonies on the membrane surface. The experimental results are shown in Figure 6 .

[0059] It can be seen from Figure 6 that after the electrode-sensitive membrane is modified with the antifouling magnetic material, the quantity of biological attachment is reduced by about 56%. This result further proves the anti-biological attachment ability of the fabricated antifouling electrode. After the magnetic-induced antifouling layer is renewed, there are almost no bacteria on the surface of the sensitive membrane, indicating that the renewal can restore the fouled membrane surface to a state close to the initial state. The above results show that the polymer membrane potential type antifouling sensor based on the magnetic antifouling functional material modification of the present invention not only has good anti-adhesion and bactericidal functions, but also can realize the renewal of the antifouling layer and has long-term, highly efficient and stable antifouling ability.

[0060] Example 5

[0061] Taking the detection of potassium ions as an example, the specific preparation steps of the renewable polymer membrane potential type antifouling sensor based on the magnetic antifouling functional material modification are as follows:

[0062] a. Preparation of the potassium ion-selective membrane solution First, weigh 1 mg of the potassium ion carrier valinomycin, 0.6 mg of the ion exchanger NaTFPB, 32.8 mg of the polymer substrate PVC, and 65.6 mg of the plasticizer o-NPOE in a weighing bottle, then measure and add 0.8 mL of redistilled THF, and stir at room temperature for 2 h to obtain a potassium ion-selective membrane solution with a uniform concentration.

[0063] b. Pretreatment process of the disk electrode: Taking the magnetic glassy carbon disk electrode as an example, after the polished disk electrode is ultrasonically cleaned with absolute ethanol and deionized water, the electrode surface is dried with nitrogen. Using the magnetic glassy carbon disk electrode as the working electrode, the Ag / AgCl electrode as the reference electrode, and the platinum wire electrode as the counter electrode, the electrodes are immersed in a solution of 0.1 M poly(sodium 4-styrenesulfonate) (NaPSS) and 0.01 M 3,4-ethylenedioxythiophene (EDOT). After electrodeposition at a constant current of 0.01414 mA for 714 s, 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.

[0064] c. Preparation of the potassium ion-selective electrode: After the disk electrode with the PEDOT(PSS) conduction layer deposited on its surface is cleaned and dried at room temperature, 100 μL of the above-obtained polymer potassium ion-selective membrane solution is modified on its surface by the drop-coating method. Then, the modified disk electrode is placed in a constant-temperature drying oven and dried overnight for standby. The above-obtained potassium ion-selective electrode is placed in 10 -3 M KCl solution and activated overnight.

[0065] d. Modification of the magnetic anti-fouling functional layer: Refer to the modification method in Example 1d.

[0066] At the same time, different ion-selective carriers (such as lead ion carrier, copper ion carrier, etc.) are added during the preparation process of the ion-selective sensitive membrane described in Example 1 or 5. Then, according to the magnetic functional material modification process described in Example 1, an anti-fouling polymer membrane electrode for measuring different ions can be obtained, and the same effect as above can be achieved. It can be seen that the universality of this method.

Claims

1. An updatable polymer membrane potential type anti-fouling sensor, characterized in that: The polymer film potential type anti-fouling sensor is composed of a disk electrode, a polymer film and a magnetic material anti-fouling layer; the polymer film is coated on the surface of the conductive substrate of the disk electrode, and a magnetic material anti-fouling layer is self-assembled on the surface of the polymer film by the action of magnetic field force; among them, the disk electrode is magnetic; The magnetic material anti-fouling layer is based on Fe3O4, and a hydrophilic material and a cationic polymer are loaded on its surface to form a composite magnetic material with dual anti-fouling functions; The composite magnetic material with dual anti-fouling function is prepared by placing Fe3O4 synthesized by the kettle-boiling method in a solution containing dopamine (DA) and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium] propane-1-sulfonate inner salt (SBMA), stirring and mixing evenly, so that a polydopamine (PDA)-polyethyl dimethylpropyl ammonium methacrylate (PSBMA) coating Fe3O4@PDA-PSBMA is formed on the surface of Fe3O4. Then, Fe3O4@PDA-PSBMA is added to an aqueous solution of dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (QAC C18 ), and stirred at 40-60 °C for 6-8 hours, and covalently bonded to the surface of the hydrophilic coating to form a composite magnetic material Fe3O4@PDA-PSBMA@QAC with dual anti-fouling function C18 .

2. The updatable polymer membrane potential type anti-fouling sensor according to claim 1, characterized in that: The composite magnetic material with dual anti-fouling functions realizes anti-bacterial adhesion by using the super-hydrophilicity of the material and realizes antibacterial performance by using the bactericidal property of the material.

3. The updatable polymer membrane potential type anti-fouling sensor according to claim 1, characterized in that: The polymer film is prepared by mixing an ion-selective carrier, a lipophilic ion exchanger, a membrane substrate material and a plasticizer according to a weight ratio of 0.2-10:0.1-5:20-40:40-80, then dissolving it in a tetrahydrofuran solution, and then dropping it on the surface of the disk electrode and naturally volatilizing it at room temperature.

4. The updatable polymer membrane potential type anti-fouling sensor according to claim 1, characterized in that: The polymer film potential type anti-fouling sensor is to insert a conventional magnetic disk electrode coated with a polymer film at the bottom into an aqueous solution containing the magnetic material anti-fouling layer for 1-10 minutes, and then the magnetic material anti-fouling layer is uniformly fixed on the surface of the electrode polymer film under the induction of magnetic field force.

5. The updatable polymer membrane potential type anti-fouling sensor according to claim 1, characterized in that: The polymer film electrode modified with the anti-fouling magnetic material is immersed in deionized water and acted under the action of an externally applied opposite magnetic field force for 10-30 minutes to remove the anti-fouling layer on the surface of the electrode, thereby realizing replacement.

6. The application of the updatable polymer membrane potential type anti-fouling sensor according to claim 1, characterized in that: The application of the polymer film potential type anti-fouling sensor in anti-biofouling during the detection of common cations in environmental water bodies.

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