Aptamers against viruses: Selection strategies and bioanalytical applications

Viruses are infectious agents that can only replicate inside cells. Tests available to make an early and effective diagnosis of viral diseases are mainly based on PCR, the gold-standard method, or in the detection of virus antigens or antibodies against them. The need for rapid diagnostic tests postulates aptamers as an alternative to antibodies. Aptamers are short single-stranded nucleic acid molecules that are selected through an in vitro process called SELEX. They show numerous advantages over antibodies, such as greater stability and chemical synthesis that minimizes variability between batches. However, they still have some limitations, for example, their low commercial availability, or the absence of standardized protocols for their characterization. In this work, different approaches for selecting aptamers against viruses are presented, as well as their targets, sequences, and binding affinities. Recent efforts aimed to develop aptamer-based methods for viral detection, using optical, electrochemical and piezoelectric transduction, are critically reviewed.