This article reviews the challenges and advances in the isolation and characterization of small-molecule-binding DNA aptamers and their use in sensors.
Aptamers are short oligonucleotides isolated in vitro from randomized libraries that can bind to specific molecules with high affinity and offer some advantages relative to antibodies as biorecognition elements in biosensors; however, it remains difficult and labor-intensive to develop aptamer-based sensors for small-molecule detection a given application. This article first discusses in vitro methodologies for the isolation of aptamers and provides guidance on selecting the appropriate strategy for generating aptamers with optimal binding properties for a given application. It next examines techniques for characterizing aptamer–target binding and structure. It then discusses various small-molecule sensing platforms based on original or engineered aptamers and their detection applications. The article concludes with a general workflow to develop aptamer-based small-molecule sensors for real-world applications. (publisher abstract modified)