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, Ti3C2 nano sheets (Ti3C2 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 Ti3C2 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 Ti3C2 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 x 10(-11) to 1.0 x 10(-8) M, and evaluated subsequently in the real blood samples with satisfactory results. This work highlights Ti3C2 MXenes as a nano material mimic enzyme (called nanozyme) for monitoring biomolecules by target-specific recognition strategy.

Automated summary

MXenes, especially Ti3C2 nano sheets, exhibit intrinsic peroxidase-like activity and can be enhanced by ssDNA, enabling a label-free colorimetric detection strategy for biomolecules. This biosensor utilizes the specific binding of aptamers to targets, causing a decrease in catalytic activity, with successful detection of thrombin in real blood samples. Ti3C2 MXenes are highlighted as a nanozyme for biomolecule monitoring through target-specific recognition.