Evolution of multi-functional capillary electrophoresis for high-efficiency selection of aptamers

Aptamers have drawn considerable attention as newly emerging molecular recognition elements in clinical diagnostics, drug delivery, therapeutics, environmental monitoring, and food safety analyses. As the in vitro screening antibody analogs, aptamers are enabled to recognize various types of targets with high affinity and specificity like or even superior to antibodies. However, the restrictions and inefficiency of selection have been hampering their wider application. Among various modified systematic evolution of ligands by exponential enrichment (SELEX) methods, capillary electrophoresis (CE)-SELEX holds multiple functions and advantages with the powerful qualitative and quantitative analysis capabilities, less consumption of sample and analytical reagent, natural binding environment, higher screening efficiency, and availability in multiple modes. This review summarizes the key developments in the area of CE-SELEX by leading research groups, including our teams' ten years of research and experience to help researchers fully understand and utilize CE-SELEX. Aptamers' history, applications, as well as the SELEX developments, have been briefly described; the advantages of CE-SELEX are highlighted compared with the conventional SELEX methods. Further, we describe some essential CE-SELEX models and provide an overview of the CE-SELEX, including the targets and ssDNA library, every technical point in the selection process, and post-SELEX protocol. We expect this review will inspire more researchers to have insight into the screening problems from CE-SELEX viewpoint and will help to improve the selection efficiency and probability of success to meet the growing needs of aptamers' discovery in bioanalytical and medical fields.