关键词: 分子印迹技术, 电场, 分子印迹聚合物, 样品前处理, 综述

Abstract:

Molecular imprinting technology （MIT） simulates the specific recognition mechanism between antibodies and antigens， and can construct separation media with specific recognition performance， demonstrating unique advantages in the fields of separation， purification， and trace detection in complex sample matrices. Molecularly imprinted polymers （MIPs）， the core of MIT， form three-dimensional imprinting cavities matching the spatial structure and chemical properties of the target substance via three key steps： template self-assembly with functional monomer， cross-linking polymerization， and template elution. The prepared MIPs present highly selective extraction and recognition of the target substance. However， traditional MIT faces critical challenges in material preparation and application. During MIPs synthesis， due to the randomness of polymerization reactions， the resulting MIPs often have uneven distribution of imprinting sites and lack molecular orientation. This not only reduces the mechanical performance of MIPs， but also affects their specific recognition performance. In addition， incomplete removal of template molecules severely reduces the number of effective imprinting sites and may interfere with the accuracy of subsequent detection results. In the pre-treatment application of MIPs adsorbents， the mass transfer rate of the target substance in the sample solution is slow， which prolongs the adsorption equilibrium time of MIPs on it. In the sensor detection based on MIPs， there are inherent issues such as fluorescence quenching and insufficient signal amplification， which further limit the detection sensitivity. These challenges significantly limit the application of MIT in fields like environmental monitoring， biomedical diagnostics， and food safety analysis. In recent years， the cross fusion of electric field assisted technology and MIT has provided innovative strategies to solve the above-mentioned problems. During MIPs preparation， an external electric field can be applied to provide electrophoretic driving force to assist in regulating the directional self-assembly of functional monomers and template molecules. This can promote the ordered arrangement of imprinting sites at the micro level of MIPs prepared， achieving material uniformity of MIPs. For template molecule elution， applying an electric field can provide electrostatic repulsion between MIPs and template molecules. This can effectively weaken the inter-molecular forces between MIPs and template molecules， facilitate the diffusion of template molecules into the desorption solution， reduce the residual template molecules， and avoid the detection of “false positives”. During the sample pretreatment process， electrophoretic force significantly enhances the mass transfer rate of the target substance， prompting it to aggregate around the MIPs adsorbent and achieve the purpose of pre-concentration. This can not only shorten the adsorption equilibrium time of MIPs for target substances， achieve rapid enrichment， but also effectively drive away interfering substances with opposite electrical properties， improving the selective extraction performance of MIPs for target substances. In the detection and analysis stages， the signal enhancement effect induced by the electric field can significantly improve the response sensitivity of the sensor. Combining with electrochemical and fluorescence detection methods， ultra sensitive detection of the target substance can be achieved. Moreover， MIP-based sensors can be integrated with microfluidic technology to achieve rapid detection and analysis of trace samples， greatly expanding the practicality of MIPs in on-site detection and analysis applications. The present review systematically elaborates the mechanism of electric field in the three key links of MIPs preparation， sample pretreatment and detection analysis. At the same time， it summarizes the application prospects of electric field assisted MIT in environmental monitoring， biomedical， food safety and other fields. In addition， the future development direction of electric field assisted MITs is proposed.

Key words: molecular imprinting technology （MIT）, electric field, molecularly imprinted polymers （MIPs）, sample pretreatment, review