Inhibition effect-involved colorimetric sensor array based on Ln-Ru dual-site nanozymes for thiol discrimination

The inhibitory interaction between nanozymes and thiols has been extensively investigated and developed for the establishment of thiol sensors. However, owing to the structural similarities of various thiols, the accurate distinction of thiols still remains a great challenge. Herein, a series of lanthanide-doped RuO₂ nanozymes (Ln-RuO_x) featuring Ln-Ru dual sites are developed and demonstrate enhanced peroxidase-like activity. Inhibition kinetics demonstrate that thiols induce a mixed inhibition mode on the Ln-RuO_x nanozymes, in contrast to the competitive mode on the RuO₂ nanozymes. Besides, by regulating the Ln elements in Ln-RuO_x nanozymes, the inhibitory interaction between Ln-RuO_x nanozymes and thiols is significantly changed, as evidenced by the inhibition constant, thus achieving the accurate distinction of various thiols. Finally, based on the differential inhibitory effects, a multichannel sensor array is established to discriminate six thiols with a detection limit of 1 μM. More importantly, this colorimetric sensor array discriminates between normal and cancer cells based on endogenous thiols, demonstrating its powerful application prospects in disease diagnosis.