Aptamer-based monitoring of drug uptake into cells and vertebrates

Sensing small molecules, including drugs and their metabolites inside cells, is critical for drug discovery and development, diagnostics, and precision medicine. To facilitate sensitive, long-term studies of drug uptake in cultured cells and animals, we developed a genetically-encoded aptamer biosensor platform for non-invasive real-time measurements of drug distribution. We combined the high specificity of aptamer molecular recognition with the easy-to-detect properties of fluorescent proteins. We tested six different aptamer biosensors, showcasing the platform versatility. The biosensors display high sensitivity and specificity for detecting their specific drug target over related analogs. Furthermore, the biosensor responses were dose dependent and could be detected in individual live cells. We designed our platform for easy integration into animal genomes; thus, we incorporated one aptamer biosensor into zebrafish, an important model vertebrate. The biosensor was stably expressed and enabled non-invasive drug biodistribution imaging in whole animals across different timepoints. To our knowledge, this is the first example of an integrated aptamer biosensor encoded by a vertebrate animal. As such, our aptamer encoded biosensors address the need for non-invasive whole animal biosensing ideal for pharmacokinetic-pharmacodynamic analyses that can be expanded to detect diverse molecules of interest. Furthermore, due to the lack of species-specific machinery, our biosensors can be potentially adapted for any model organism of interest.