Engineering a "dual-key-and-lock" ratiometric fluorescent nanoprobe for real-time reporting the freshness and quality of meat

Accurate and real-time reporting the freshness and quality of meat has far-reaching implications for safeguarding food safety and public health. Owing to the significant indicator role of H2S in meat spoilage, we here designed a ``dual-key-and-lock'' kind of H+-powered H2S-responsive ratiometric fluorescent nanoprobe BODIPY/ Cy7Cl@HyNPs for precise and real-time evaluating the meat freshness. After incubation with spoilt meat, BODIPY/Cy7Cl@HyNPs was simultaneously initiated by the abnormal H+ and H2S acted as "dual-keys". As a result, the fluorescence emission of BODIPY/CyCl@HyNPs at similar to 688 nm was enhanced, and the other emission at similar to 818 nm was quenched, thereby yielding a typical H+-powered ratiometric fluorescence response toward H2S in meat. In addition, we also successfully exploited BODIPY/Cy7Cl@HyNPs to achieve the real-time monitoring of the meat freshness during storage by measuring the changes of fluorescence signals and solution color.