CN-117554452-B - Method for preparing wearable potential ion sensor based on conductive polymer nanofiber membrane

CN117554452BCN 117554452 BCN117554452 BCN 117554452BCN-117554452-B

Abstract

A method for preparing wearable potential ion sensor based on conductive polymer nanofiber membrane belongs to the field of electrochemical sensing. The method mainly comprises the following steps of (1) successively dripping a conductive polymer monomer solution and an initiator-cross-linking agent mixed solution on the surface of an electrode, wherein the conductive polymer monomer solution and the initiator-cross-linking agent mixed solution induce monomer assembly polymerization, obtain a conductive polymer nanofiber membrane and dry the conductive polymer nanofiber membrane, (2) preparing an ion selective membrane dispersion liquid according to a certain proportion, dripping the ion selective membrane dispersion liquid on the electrode, drying the electrode to form a membrane, and (3) placing the prepared electrode in a prepared standard ion solution (ions to be detected) for pretreatment after being dried overnight in a dark place, and (4) placing the electrode in ion solutions with different concentrations for testing, so as to obtain the relation between ion concentration and voltage, obtain a standard curve and a linear equation, and realize monitoring of ion concentration in sweat. The wearable potential ion sensor prepared by the method is used for carrying out high-sensitivity real-time monitoring on ions in sweat.

Inventors

YIN MINGJIE
YANG YAQIONG
Lv tianrun
AN QUANFU

Assignees

北京工业大学

Dates

Publication Date: 20260508
Application Date: 20231108

Claims (6)

1. A method for preparing a wearable potentiometric ion sensor based on a conductive polymer nanofiber membrane, comprising the steps of: (1) Dissolving conductive polymer monomer in solvent, stirring to dissolve fully to obtain monomer solution A, dissolving initiator and four-claw cross-linking agent in solvent, stirring to dissolve fully to obtain solution B; (2) Respectively dripping the solution A and the solution B on an electrode, and reacting the solution A and the solution B on the surface of the electrode to obtain a conductive polymer nanofiber membrane; (3) Preparing ion selective membrane dispersion liquid according to a certain proportion; (4) Dripping the ion selective membrane dispersion prepared in the step (3) onto the conductive polymer nanofiber membrane obtained in the step (2), and drying to form a membrane; (5) Drying the prepared electrode overnight in dark, and then placing the electrode in a prepared 0.1M ion solution to be tested for pretreatment; (6) Placing the electrode in the step (5) in ion solutions with different standard concentrations to be tested to obtain the relation between the ion concentration and the voltage, and obtaining a standard curve and a linear equation to realize the monitoring of the ion concentration; the conductive polymer monomer in the step (1) is selected from pyrrole, aniline or thiophene, and the mass fraction of the monomer in the solution A is 10% -30%; The 'four-claw' cross-linking agent is selected from copper tetrasulfonate, zinc tetrasulfonate, iron tetrasulfonate, zinc phthalocyanine tetracarboxylate or tetra amino iron phthalocyanine, and the molar concentration of the cross-linking agent in the solution B is 7 mu M-10 mu M; The volume ratio of the solution A to the solution B in the step (2) is 1:2.
2. The method according to claim 1, wherein the initiator is Ammonium Persulfate (APS) or ferric chloride (FeCl 3 ) in the amount of 0.1 to 1% by mass in solution B.
3. The method according to claim 1, wherein the composition of the ion selective membrane dispersion in the step (3) is that polyvinyl chloride, dioctyl sebacate, tetra [3, 5-di (trifluoromethyl) phenyl ] sodium borate and different ionophores are dissolved in cyclohexanone, and the mass percentage of the polyvinyl chloride, dioctyl sebacate, tetra [3, 5-di (trifluoromethyl) phenyl ] sodium borate and the ionophores is 32-35%, 62-65%, 0.4-0.6%, 1-3%.
4. The method of claim 3, wherein the different ionophores are selected from the group consisting of K + carrier, NH 4 + carrier, na + carrier, ca 2+ carrier, cu 2+ carrier, cl - carrier, and Pb 2+ carrier.
5. A wearable potentiometric ion sensor based on a conductive polymer nanofiber membrane prepared according to the method of any one of claims 1-4.
6. The application of the wearable potential ion sensor based on the conductive polymer nanofiber membrane prepared by the method according to any one of claims 1-4 can realize detection of various ions by directly wearing the sensor on the skin, and has high sensitivity and quick response time.

Description

Method for preparing wearable potential ion sensor based on conductive polymer nanofiber membrane Technical field: the invention relates to a wearable potential ion sensor with a conductive polymer nanofiber membrane as an ion-electron transduction layer and application thereof in sweat monitoring, belonging to the field of electrochemical sensing. The background technology is as follows: Ions are key to maintaining normal operation of cells in vivo, and ions such as sodium, potassium and calcium are involved in important biochemical processes such as cell membrane potential regulation and cell signaling. However, when the ion concentration is too high or too low, dysfunction or even failure of various organs such as nervous system, cardiovascular system, muscular system, etc. may result. Monitoring the change of the ion content in the human body in real time is important for preventing diseases. Blood tests can accurately obtain the concentration of ions in the body. However, this method is prone to trauma and infection risk, and it is difficult to record information changes in real time, possibly missing the optimal treatment period in the initial stage of the onset. Therefore, a sensor for noninvasively and continuously monitoring the ion concentration in the body is developed, which is beneficial to optimizing the use of medical resources and guaranteeing the health of human bodies. Wearable Potentiometric Ion Sensors (WPIS) can obtain relevant health information in real time by detecting active ingredients in secretions, such as sweat. But the concentration of ions in sweat is much lower than in blood. Therefore, improving the sensitivity and detection limit of WPIS is a key to achieving accurate monitoring of ions in sweat. The core determining WPIS performance is the solid contact ion selective electrode, where the ion-electron conversion membrane is critical for signal transmission. The conductive polymer has the advantages of capability of conducting ions and electrons simultaneously, solution processability, easiness in regulation and the like, and is widely used for the ion-electron conversion film of the WPIS. However, the conductive polymer film is generally prepared by aggregating conductive polymer nano particles, so that the mass transfer resistance of electrons/ions is increased, the active surface area of the conductive polymer film is reduced, and the sensitivity and the detection limit of the conductive polymer film are low, so that the requirement of low-concentration ion test cannot be met. If the conductive polymer can be prepared into a wire-like nanofiber shape, the mass transfer of electrons/ions in the conductive polymer film can be enhanced and the active area of the conductive polymer film can be increased, so that the WPIS with high sensitivity and wide range can be obtained for long-term monitoring of the change of the concentration of K + in sweat (Kim, H.J., adaptation 2019,25,1259-1269). The invention adopts a supermolecular chemical method to control the self-assembly orientation of the conductive polymer in situ, prepares a conductive polymer film with nanofiber shape on a flexible electrode substrate, and obtains the WPIS for monitoring the concentration change of ions in sweat in real time by depositing the ion selective permeable film. In the polymerization process of the conductive polymer, a 'four-claw' cross-linking agent is utilized to regulate the unidirectional growth of chain segments in the polymerization process of the conductive polymer, so that a nanofiber-shaped conductive polymer chain with a high length-diameter ratio is obtained, and meanwhile, the cross-linking agent has a doping effect on the conductive polymer, so that the conductivity of the conductive polymer is improved. In the test, the ion-selective permeable membrane dedopes the conductive polymer membrane, which is reduced, creating a potential difference. The conductive polymer nanofiber with high length-diameter ratio can improve the reaction and mass transfer speed of electrons/ions in the dedoping process, and improve the sensitivity of WPIS and response time of the WPIS. By regulating the morphology of the conductive polymer chain segment, the electron/ion mass transfer barrier is reduced, the reaction site is increased, and the performance of the sensor can be obviously improved. By measuring the relation between the potassium ion concentration and the voltage of the polypyrrole nanospheres WPIS, the linear equation is y=0.107+0.0322, the polypyrrole nanofiber WPIS is y=0.227+0.062x, the slope of the equation is sensitivity, and the optimized polypyrrole nanofiber-based WPIS can realize high sensitivity of 62mV decade –1 in K + detection, which is superior to 32mV decade –1 of the polypyrrole nanospheres, and the WPIS has a wide detection range, namely 0.05-100mM (the concentration of K + in covering sweat). The method has the advantages of mild preparation conditions, simple operation an