Current Status and Challenges of Aptamers Screening and Optimization

Aptamers, consisting of single-stranded DNA or RNA, have secondary and tertiary structures which could bind specifically to target molecules. They are characterized by strong specificity, high affinity, low molecular weight, and low immunogenicity; therefore, the current research focuses on their potential as a targeted drug carrier, a diagnostic probe for diseases, or as a direct therapeutic drug.In this review, how to improve the success rate of adaptor screening and the optimization after screening is described.For aptamer screening, an efficient selection strategy is needed. In this article, by analyzing key aspects of SELEX such as initial library design, screening procedures, truncation and modification after screening, a comprehensive analysis of each step that might meet obstacles in SELEX is provided.Aptamers, which possess the specificity and affinity with the target, can serve as targeted drug carriers or biosensors for diagnosing a disease. If the problems in the screening process in cell-SELEX technology, truncation, and modification after screening are solved, it will have a broader range of applications.