MXene-Ti3C2/CuS nanocomposites: Enhanced peroxidase-like activity and sensitive colorimetric cholesterol detection.

Nanomaterials with enzyme-like activity have attracted much attention recently. Herein, we report the synthesis of a new type of 2D MXene-Ti3C2/CuS nanocomposites with peroxidase-like activity using a simple hydrothermal approach. Significantly, compared with the individual MXene-Ti3C2 nanosheets or CuS nanoparticles, the MXene-Ti3C2/CuS nanocomposites show a synergistically enhanced peroxidase-like activity and can be used as an efficient mimetic peroxidase to catalyze the reaction of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2), causing a blue color change. Kinetic studies reveal that the MXene-Ti3C2/CuS nanocomposites have a higher catalytic activity to TMB than their single components, and the catalytic reaction follows the ping-pong mechanism. The MXene-Ti3C2/CuS nanocomposites are used for the colorimetric determination of cholesterol with a linear range of 10-100 μM and a limit of detection (LOD) of 1.9 μM. Our results show that the MXene-Ti3C2/CuS nanocomposites based colorimetric cholesterol biosensor is cost-effective, sensitive, and selective, which has potential application in H2O2 and cholesterol detection and clinic medicine diagnostics.