Implantable Fluorogenic DNA Biosensor for Stress Detection

Implantable sensors that can monitor analytes related to cognitive and physiological status have gained significant focus in recent years. We have developed an implantable biosensor to detect dehydroepiandrosterone sulfate (DHEA-S), a biomarker related to stress. The biosensor strategy was based on the principle of forced intercalation (FIT) aptamers designed to detect subtle intramolecular changes during aptamer-target binding events. By incorporating a steroid-specific fluorogenic aptamer into a hydrogel, the sensitivity and biostability of the FIT biosensor fiber were improved, which were essential for designing implantable sensors to monitor biomarker levels in the living body. The polyethylenimine-based hydrogel chosen for this study produced an optically transparent cross-linked network with optimal microstructure, physicochemical, and mechanical properties, making it suitable for optical biosensors. The