Ti3C2 MXenes with intrinsic peroxidase-like activity for label-free and colorimetric sensing of proteins

MXenes are attractive for various biosensors owning to their tunable versatile properties. Herein, Ti 3 C 2 nanosheets (Ti 3 C 2 NSs) were found to possess intrinsic peroxidase-like activity, and which could be enhanced by single-stranded DNA (ssDNA) adsorbed on the nanosheets. Hence, a simple label-free sensing strategy was developed for colorimetric detection of biomolecules, based on Ti 3 C 2 NSs as a peroxidase mimic enzyme and ssDNA aptamer as an enzymatic activity enhancement factor along with a recognition substance for the target. In the presence of target biomolecules, the aptamers were desorbed from Ti 3 C 2 NSs due to the specific binding of targets to aptamers, thus bringing about the decrease of catalytic activity. Thrombin (TB) as the model was determined by this constructed biosensor with a linear range of 1.0 × 10 −11 to 1.0 × 10 −8  M, and evaluated subsequently in the real blood samples with satisfactory results. This work highlights Ti 3 C 2 MXenes as a nanomaterial mimic enzyme (called nanozyme) for monitoring biomolecules by target-specific recognition strategy.