Nanomaterial-Based Electrochemical and Optical Biosensors for Sedative Drug Detection: Mechanistic Insights and Point-of-Care Applications.

Therapeutic sedatives, including benzodiazepines, barbiturates, and Z-drugs, are widely prescribed for anxiety, insomnia, and related disorders but are associated with dependence, overdose, and abuse, creating a need for rapid and selective monitoring. Conventional analytical techniques provide high accuracy but remain limited by cost, infrastructure requirements, and poor portability. Recent advances in nanomaterial-based electrochemical and optical biosensors have enabled sensitive and point-of-care detection of sedatives in complex biological and environmental matrices. This review critically evaluates electrochemical, fluorescence, colorimetric, and SERS-based sensing platforms, with emphasis on nanomaterial-analyte interactions, sensing mechanisms, and structure-function relationships governing analytical performance. Platform-specific advantages, limitations, multiplexing capability, and challenges associated with real-sample analysis and point-of-care translation are discussed, together with emerging directions in AI-assisted, smartphone-integrated, and wearable biosensing.