Current Status and Challenges of Aptamers Screening and Optimization

Background: 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. Objective: In this review, how to improve the success rate of adaptor screening and the optimization after screening is described. Results: 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. Conclusion: 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.