Colorimetric detection of creatinine based on specifically modulating the peroxidase-mimicking activity of Cu-Fenton system

Creatinine (CR) has always been considered as a prime important indicator for evaluating of renal dysfunction. Nevertheless, the literature still lacks in methods that fulfill the requirements for detecting CR effectively. Therefore, the development of a visual sensing method for the detection of CR specifically and sensitively is definitely desirable. To provide a solution, a colorimetric sensing platform for monitoring CR was constructed based on the regulation effect of CR on the peroxidase-mimicking activity of MoO3-Cu2+ system. Here, the prepared MoO3 itself does not have the catalytic activity of peroxidase mimics, but it can be used as a co-catalyst. In the presence of CR, the Cu2+ Fenton-like reaction can be promoted through co-catalysis of MoO3, so as to facilitate the production of more reactive oxygen species (ROS) and accelerate the oxidation process of 3,3',5,5'-tetramethylbenzidine (TMB). As a result, the regulation of MoO3-Cu2+ peroxidase-like activity can be achieved by adding different concentrations of CR. The higher the concentrations of CR, the stronger the catalytic activity for MoO3-Cu2+/CR. Experimental results showed that the colorimetric sensing strategy proposed in this paper can be successfully applied to the analysis of CR in human serum samples.