Research progress on evaluation methods of binding affinity of nucleic acid aptamer

Nucleic acid aptamers which can be synthesized in vitro have attracted more and more attention in the field of life and health, and their binding affinity with targets is one of the important performance indexes. There are many methods to evaluate the binding affinity of nucleic acid aptamers. We screen and classify the technical methods, and describe the basic principle, research progress, and bottleneck problems of each technical method in detail. Mature methods for evaluating the binding affinity of nucleic acid aptamers include surface plasmon resonance, biological layer interference, enzyme-linked aptamer assay, and quartz crystal microbalance. These techniques can stably and sensitively capture molecular binding signals, which significantly promote the research progress of nucleic acid aptamer technology. However, the traditional aptamer immobilization technology may have a certain impact on the molecular conformation, thus changing its actual binding affinity in the environment. In order to solve this problem, researchers are actively exploring new methods to evaluate the binding affinity of molecules without immobilization, such as circular dichroism, UV–visible absorption spectroscopy, fluorescence anisotropy, fluorescence spectroscopy, isothermal titrition calorimetry, gel retardation, microscale thermophoresis, and flow induced dispersion analysis. The continuous progress of these new technologies and methods will greatly promote the innovation of nucleic acid aptamers in the fields of screening and application, and pave the way for further commercialization of nucleic acid aptamers.