Wireless portable MEMS sensor with mesoporous yolk-Shell SnO2/TiO2 Nanospheres for real-time and nondestructive freshness monitoring of aquatic products.

Rapid and reliable detection of trimethylamine (TMA), a key spoilage indicator in aquatic products, is of critical value for real-time freshness monitoring and food safety control. Herein, mesoporous yolk-shell SnO2/TiO2 nanospheres were utilized as sensing materials to construct a wireless and portable microelectromechanical system-based sensing platform for nondestructive aquatic product freshness evaluation. The optimized SnO2/TiO2-2 sensor exhibited a high response (Ra/Rg = 53.2@100 ppm TMA), fast response/recovery times (7.7 s/10.8 s), and superior selectivity. The signal of the detection device, which is integrated with this sensor, was positively correlated with total volatile basic nitrogen (TVB-N) content measured via the standard reference method. The receiver operating characteristic (ROC) analysis was also performed to determine the optimal classification threshold for discriminating between fresh and spoiled states. These results demonstrate that the proposed platform provides a practical, cost-effective solution for real-time freshness monitoring across the entire aquatic product supply chain.