Development of Better Aptamers: Structured Library Approaches, Selection Methods, and Chemical Modifications

Abstract

Systematic evolution of ligands by exponential enrichment (SELEX) has been used to discover thousands of aptamers since its development in 1990. Aptamers are short single‐stranded oligonucleotides capable of binding to targets with high specificity and selectivity through structural recognition. While aptamers offer advantages over other molecular recognition elements in their ease of production, smaller size, extended shelf‐life, and lower immunogenicity, they have yet to show significant success in real‐world applications. By analyzing the importance of structured library designs, reviewing different SELEX methodologies, and the effects of chemical modifications, we provide a comprehensive overview on the production of aptamers for applications in drug delivery systems, therapeutics, diagnostics, and molecular imaging.

Recent Advances in Aptamer-Based Biosensors for Bacterial Detection

“…Furthermore, we discuss the principal methodologies and techniques used to enhance the overall efficiency and functionality of aptamers for improved target detection. Recently, two reviews have described aptamer identification, the transducer technologies used in aptasensors and nanomaterials for aptasensors [17][18][19][20][21][22][23]. Differing from these reports, the current review aims to demonstrate the present circumstances and the prospects of various aptasensors for the detection of pathogenic bacteria.…”

Site-Directed Electrochemical Grafting for Amplified Detection of Antibody Pharmaceuticals

“…Over the past decades, many methods have been reported for the selective detection of antibody levels. − In addition to liquid chromatography–mass spectrometry (LC–MS)-based methods that do not require the use of an affinity ligand, a variety of methods utilizing antibodies, peptide mimotopes, and aptamers, , as the affinity ligands have been reported, such as the surface plasmon resonance (SPR), chemiluminescent, photoelectrochemical (PEC), bioluminescent, fluorescent, , quartz crystal microbalance (QCM), and electrochemical methods. − Among these methods, the electrochemical aptamer-based (E-AB) detection of antibody pharmaceuticals has received increasing attention, largely due to the good portability, low sample consumption and detection cost, and uncomplicated instrumentation. , On the basis of the binding-induced conformational change of the ferrocene (Fc)-modified DNA aptamer, for example, Nagata et al reported an E-AB method for the one-step detection of bevacizumab, with a detection limit of 9.1 nM . This method is easy to operate, low-cost, and highly selective; however, the “signal-off” detection can result in false-positive responses while the detection sensitivity remains to be further improved.…”

Chemistry and Biology of Noncanonical Nucleic Acid Structures: From Physicochemical Properties to Therapeutic Applications

“…Many nucleic acid aptamers, characterized by their propensity to adopt specific structural conformations, also fold into noncanonical structures, thus forming unique threedimensional architectures capable of specifically recognizing their targets at the molecular level [12,13]. Moreover, the nanoscale geometry and dynamic properties of noncanonical nucleic acid structures, along with their inherent biocompatibility, make them promising candidates for the development of functional nanodevices [14,15].…”