A simple Ag-MoS₂ hybrid nanozyme-based sensor array for colorimetric identification of biothiols and cancer cells

The intracellular levels of biothiols are associated with various diseases including cancer, and biothiols are regarded as tumor biomarker. Due to the similarity of the molecular structure of biothiols, the development of simple, rapid, efficient, and sensitive colorimetric sensor arrays holds great promise for clinical cancer diagnosis. Here, we developed a simple Ag-MoS₂ hybrid nanozyme-based sensor array for colorimetric identification of biothiols and cancer cells. The novel Ag-MoS₂ nanoprobe was synthesized in a simple and efficient way through the in situ self-reduction reaction between MoS₂ and noble metal precursor. Benefiting from to the formation of heterogeneous metal structures, the peroxidase (POD)-like catalytic activity of the synthesized Ag-MoS₂ hybrid nanocomposites is significantly enhanced compared to MoS₂ alone. Moreover, the catalytic activity of Ag-MoS₂ nanozyme was correlated with the pH of the reaction solution and the inhibitory effects of the three biothiols on the nanozyme-triggered chromogenic system differed in the specific pH environments. Therefore, each sensing unit of this electronic tongue generated differential colorimetric fingerprints of different biothiols. After principal component analysis (PCA), the developed novel colorimetric sensor array can accurately discriminate biothiols between different types, various concentrations, and different mixture proportions. Further, the sensor array was used for the colorimetric identification of real serum and cellular samples, demonstrating its great potential in tumor diagnostic applications.