A pilot clinical trial published in Nature Biotechnology demonstrated an electrochemical, aptamer‑based wearable patch that measures drug concentrations continuously from interstitial fluid. The device provided real‑time kinetics in healthy volunteers and could enable therapeutic drug monitoring for narrow‑therapeutic‑index agents, dose optimization and adherence tracking. Authors highlighted the platform’s potential to reduce sampling burdens and accelerate pharmacokinetic studies; further work is required to validate accuracy across diverse drugs, patient populations and chronic dosing scenarios.