MnZn bimetallic cold-adapted nanozymes prepared by DBD plasma for in situ monitoring of volatile sulfur compounds and meat freshness inspection.

In this work, low-temperature plasma (LTP) technology was employed to fabricate a novel, cold-adaptive bimetallic MnZn-MOF nanozyme with triple enzyme-like activities. The MnZn-MOF nanozyme could maintain high catalytic activity at nearly 0 °C. The MnZn-MOF nanozyme could be further integrated into agarose hydrogel to construct sensor arrays. By combining the as-prepared sensor arrays with smartphone together with the assistance of machine learning for data analysis, non-destructive detection of volatile sulfur compounds (VSCs) and accurate classification and prediction of meat freshness were achieved. As such, this work not only develops an effective plasma-assisted strategy for fabricating cold-adapted MOF nanozymes but also provides a highly sensitive sensor for trace detection of VSCs at low temperatures, which may offer a promising approach for efficient on-site assessment of meat freshness as well as food safety in practice.