RESUMEN

Ion concentration polarization (ICP) is an electrical transport phenomenon that occurs at the micro-nano interface under the action of an applied electric field, and the ICP phenomenon can be used to enrich charged particles with high efficiency. The microfluidic chip has the advantages of high precision, high efficiency, easy integration and miniaturization in biochemical analysis, which provides a new solution and technical way for biochemical analysis. In response to the demand for the detection of trace charged target analytes in sample solution, the advantages of high enrichment multiplicity, convenient operation and easy integration of ICP are utilized to provide an effective way for microfluidic biochemical detection. The combination of ICP phenomenon and microfluidic analysis technology has been widely used in the fields of pre-enrichment of charged particles, separation of targets, and detection of target analytes in biochemical analysis. In this paper, the principle of ICP and the microfluidic ICP chip are briefly introduced. Under the action of external electric field, the co-ions pass through the ion-selective nanochannel, the counterions are rejected at the boundary of nanochannel to form a depletion zone, and the charged samples will be enriched at the boundary of the depletion zone. Then the preparation techniques and methods of ICP chips are summarized. Among them, the design of microfluidic channel structure and the preparation and design of nanostructures are emphasized. The basic single-channel structure is analyzed, and the parallel-channel structure as well as the integrated multi-functional microfluidic ICP chip are sorted out and summarized. The preparation methods of nanostructures in ICP chips and their respective advantages and disadvantages are listed, and it is summarized that the current mainstream means are the embedding method and the self-assembly method, and attention is paid to the design of nanostructures preparation methods by both of them. In addition, this paper also discusses how to optimize the enrichment efficiency of ICP chip, through the introduction of multi-field coupling, valve control and other means to achieve the optimization of the enrichment efficiency of target substances. Meanwhile, this paper provides a classified overview of the progress of application of ICP chips in biochemical analysis and detection. ICP chips have been widely used in the research and development of biosensors, which can be used for the enrichment and separation of a variety of analytes including small molecules, nucleic acids, proteins, and cells, etc. By changing the design of microfluidic structures, integrating detection methods and modifying specific antibodies, ICP chips have shown great potential in the fields of rapid enrichment and pre-processing of targets, separation of targets and highly sensitive detection. Finally, it is pointed out that ICP chips are facing challenges in improving enrichment efficiency and selectivity, and solving the problems of fluid control, mixing and transport to match the biological properties of target assay, and that microfluidic ICP chips have been continuously promoting the development of ICP chips through the improvement of materials, chip design and integration of multifunctional units, opening up new possibilities in the field of biochemical analysis methods and applications. It can be seen that microfluidic ICP chips have the advantages of low sample flow rate, good separation and enrichment, high detection efficiency, and easy integration and miniaturization, which have shown good research significance and practical prospects in the field of biochemical detection.