Biogenic amine detection via organic nanocrystals integrated into paper-based analytical devices

Monitoring toxic biogenic amines is essential for ensuring food quality and safety. Microfluidic paper-based analytical devices (µPADs) have emerged as promising platforms for biogenic amine detection owing to their low cost, rapid response, and operational simplicity. In this study, fluorescent organic nanocrystals (NCs), specifically 3-(2-benzothiazolyl)-4-hydroxybenzenesulfonic acid (BHB), were immobilised onto µPADs for the selective detection of biogenic amines. By regulating the pH at 7.6 using a phosphate buffer, the BHB NCs showed good selectivity for histamine over other biogenic amines. Upon application of an appropriate volume of aqueous sample solution, the BHB NCs exhibited a distinct colour change, even at low concentrations, enabling the detection of biogenic amines in real samples. The proposed platform achieved a limit of detection of 15 ppm for histamine, outperforming previously reported methods and approaching the performance of a commercially available assay. Furthermore, the practical applicability of the system was validated through the successful detection of biogenic amines in tuna samples, demonstrating its potential for monitoring food spoilage.