Biogenic amine-responsive ratiometric fluorescent microneedle sensor for real-time visualization of meat freshness

A ratiometric fluorescent hydrogel microneedle (MN) patch was developed for rapid raw meat freshness detection. The sensor integrated fluorescein isothiocyanate (FITC) as a biogenic amine (BAs) indicator and rhodamine B (RhB) as an internal reference within a silk fibroin methacryloyl (SilMA) hydrogel matrix. Leveraging FITC's specific response to BAs, the patch exhibited visible color changes proportional to histamine concentrations. Optimizing FITC/RhB concentrations enabled sensitive BAs detection in meat samples within 8 min. The FITC/RhB@SilMA MN patch demonstrated high accuracy and repeatability in freshness assessment for chicken breast, pork, and salmon stored at 0 °C and 4 °C. Freshness classification was established using G + R/(R + G + B) values: <0.60 (fresh), 0.60–0.65 (low quality), >0.65 (spoiled). These values showed strong correlation with the Biogenic Amine Index (BAI), confirming method reliability. This work presents a novel on-site strategy for real-time meat quality monitoring, offering practical applications in food safety control.