A fluorescence sensor array for biothiol detection and disease identification based on a CoOOH nanoflake triggered dual-color fluorescence system

Biothiol analysis holds critical importance in disease diagnosis, but the highly similar structures of biothiols pose a major obstacle to their practical detection. Herein, a straightforward yet efficient CoOOH nanoflake (CoOOH NF)-triggered dual-color fluorescence sensor array has been developed for the discrimination of biothiols. Owing to their high oxidase-like activity, CoOOH NFs efficiently catalyze the oxidation of fluorometric signal indicators, generating diverse fluorescence signals. However, the presence of biothiols induced structural degradation of CoOOH NFs via redox etching, thereby inhibiting the fluorescence reactions. Based on the differential reducing capacities of biothiols, the sensor array produced unique fluorescence response patterns, which were further analyzed using principal component analysis (PCA) and hierarchical cluster analysis (HCA). The results demonstrated that the sensor array could reliably discriminate three biothiols (glutathione (GSH), cysteine (Cys), and homocysteine (Hcy)) across a broad concentration range (0.5–100 μM), as well as their mixtures with varying molar ratios. Importantly, this strategy was successfully applied to distinguish cancer cells from normal cells and to analyze clinical serum samples, highlighting its potential for medical diagnostics.