Exploring the bactericidal performance and application of novel mimic enzyme Co₄S₃

Novel and uniform Co₄S₃ nanoparticles were synthesized through a two-step hydrothermal process and testified to possess intrinsic peroxidase (POx)-like activity for the first time. As a fresh POx mimic, we studied its catalytic properties, kinetic, and mechanism to catalyze the oxidation of 3, 3', 5, 5'-tetramethylbenzidine in the presence of H₂O₂. According to the experiments, the bactericidal mechanism is the same as that of simulated enzyme. Based on the ability of Co₄S₃ inducing H₂O₂ to express O₂^-, the bactericidal rate can be as high as 100%. Besides, using the POx-like activity of Co₄S₃, a new off-on sensor for H₂O₂ and l-cysteine (l-Cys) detection is constructed. The sensor reveals a good wide linear response to H₂O₂ in the 40-2000 µM with a detection limit of 18 µM, while l-Cys in the 20-100 mM with a detection limit of 10 mM. The proposed method also shows great stability, high selectivity, and excellent practicability.