Development of a novel benzothiazole-based fluorescent and gel-based sensor with enhanced visual discrimination and stability.

Here, we present BTPC-Ta, a benzothiazole-based fluorescent sensor enabling ultrasensitive detection of biogenic amines (spermine/cadaverine: 0.1 nM) through visible colorimetric transitions (red-to-blue). Supported by DFT calculations, HRMS, and NMR analyses, the sensing mechanism involves structural reorganization upon analyte binding. To address traditional limitations, we engineered PD@Ta-a gel-based platform that enhances stability while maintaining sensitivity by optimizing the solvent environment. Applied to real-time shrimp spoilage monitoring, PD@Ta demonstrated quantitative correlations between reaction time, total volatile basic nitrogen (TVB-N) levels, and R/G/B chromaticity values (R2 = 0.98). This portable system combines naked-eye readability with smartphone-compatible signal digitization, achieving rapid discrimination among six biogenic amines. The integration of theoretical modeling, material innovation, and practical validation establishes a robust methodology for food safety control, offering ∼nM detection limits and operational stability exceeding 30 days. This study provides an innovative, efficient, and stable method for food safety testing.