Enhancing Food Safety with Microneedle-Based Biosensors: Real-Time Monitoring of Fish Freshness

Food, especially fish meat, is extremely vulnerable to oxidation and microbiological deterioration. Therefore, effective analytical techniques for quality control and safety monitoring are required. Electrochemical biosensors have become reliable, rapid, and affordable devices for in-field and real-time food quality assessment. However, their application is often limited in point-of-need scenarios due to the requirement for intensive sample preparation. Here, we introduce a microneedle array (MNA)-based electrochemical biosensor, designed for direct food safety and quality analysis without the need for sample preparation. A gold (Au)-coated polymeric MNA was functionalized with a chitosan-gold nanoparticles (Ch-AuNP) nanocomposite and further modified by immobilizing xanthine oxidase (XO) for selective hypoxanthine (HX) detection. The MNA-based biosensor exhibited a linear range between 5 and 50 μM, and 50 to 200 μM, with a sensitivity of 0.024 μA/μM and a limit of detection (LOD) of 2.18 ± 0.75 μM for HX, with a response time of approximately 100 s. Furthermore, the MNA-based biosensor was successfully utilized for monitoring HX levels in fish tissue samples over 48 h, showing strong agreement with results obtained from a commercial Amplex Red assay kit. The technology can be used for real-time food quality assessment and food safety monitoring due to its high sensitivity, interference tolerance, and lack of requirement for sample preparation.