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.