Boosting histamine Raman detection via dynamic competitive coordination chemistry: Ag nano-island anchored nanofiber paper from stepwise solvent evaporation co-assembly.

Creating high-performance Surface-enhanced Raman spectroscopy (SERS) substrates for histamine detection is crucial for food safety, yet remains challenging due to insufficient sensitivity, time-consuming pretreatments, and inadequate real-time sensing capabilities. Herein, an ultrasensitive nanofiber paper-based SERS platform was fabricated through co-assembly of silver ions, fluorescein isothiocyanate, and poly (vinyl alcohol-co-ethylene) nanofibers via stepwise ethanol/water evaporation. The uniform plasmonic silver nano-islands feature tiny hotspot regions, fast wetting abilities, and active coordination sites on nanofibers, achieving a hundred-fold sensitivity improvement compared to dried samples and an ultralow detection limit of 10-16 mol/L. Importantly, this platform exhibits a broad linear sensing range and enables wet-state SERS detection within 30 s of sample contact, eliminating time-consuming drying pretreatment, amplifying Raman signals, and allowing in-situ monitoring of histamine adsorption/competitive coordination dynamics via localized surface plasmon resonance. This nanopaper successfully quantified histamine levels in spoiled meat samples, demonstrating its applicability to complex food matrices and on-site meat safety control.