Macromolecule-Enriched Fluorescent Peptides Derived from Receptor Proteins for Sensitive Drug Identification via Differential Sensing

Synthetic illicit drugs have posed severe threats to health and social security. Differential sensing integrated with multivariate data processing methods provides substantial benefits for the simultaneous detection of multiple drugs. Rational design of sensing elements targets a variety of drugs, and achieving high sensitivity using nontargeted sensing elements remains a challenge. To address these challenges, we design peptide-based sensing elements through rational truncation of key recognition fragments from receptor proteins and propose a dual signal amplification strategy that leverages Förster resonance energy transfer (FRET) enhancement and macromolecule-induced probe enrichment. Two fluorogenic peptides are truncated from the binding domain of GABAA and opioid receptors. The peptides are then enriched by fluorescently tagged carboxymethyl dextran to form multicomponent complexes and trigger FRET signals. A three-channel four-complex sensor array is constructed, which can simultaneously identify 5 drugs (C = 100 nM) with 100% accuracy and different mixing ratios and achieve quantitative detection of drugs. Moreover, the array excels in distinguishing six simulated drug samples in the artificial urine. The sensor array constructed using this strategy combines high sensitivity with parallel detection capability in complex environments, offering a promising solution to the growing challenge of the detection of increasingly prevalent drugs.