Pt Decorated Ti3C2Tx MXene with NIR-II Light Amplified Nanozyme Catalytic Activity for Efficient Phototheranostics

The clinical application of photothermal therapy (PTT) is severely limited by the tissue penetration depth of excitation light, and enzyme therapy is hampered by its low therapeutic efficiency. As a two-dimensional ultrathin nano- sheet with high absorbance in the near-infrared-II (NIR-II) region, the titanium carbide (Ti3C2) nanosheet can be used as a substrate to anchor functional components, like nanozymes and nanodrugs. Here, we decorate Pt artificial nanozymes on the Ti3C2 nanosheets to synthesize Ti-based MXene nanocompo sites (Ti3C2Tx-Pt-PEG). In the tumor microenvironment, the Pt nanoparticles exhibit peroxidase-like (POD-like) activity, which can in situ catalyze hydrogen peroxide to generate hydroxyl radicals ((OH)-O-center dot) to induce cell apoptosis and necrosis. Mean-while, the composite shows a desirable photothermal effect upon NIR-II light irradiation with a low power density (0.75 W cm(-2)). Especially, the POD-like activity is significantly enhanced by the elevated temperature arising from the photothermal effect of Ti3C2Tx. Therefore, satisfactory synergistic PTT/enzyme therapy has been accomplished, accompanied by an applicable photoacoustic imaging capability to monitor and guide the therapeutic process. This work may provide an approach for hyperthermia-amplified nanozyme catalytic therapy, especially based on metal catalysts and MXene nanocomposites.

Automated summary

By using the two-dimensional ultrathin nano-sheet Ti3C2 as a substrate, Pt artificial nanozymes were decorated to synthesize Ti-based MXene nanocomposites Ti3C2Tx-Pt-PEG. In the tumor microenvironment, Pt nanoparticles exhibited peroxidase-like (POD-like) activity, generating hydroxyl radicals to induce cell apoptosis and necrosis. Meanwhile, the composite showed desirable photothermal effect under NIR-II light. Satisfactory synergistic therapy was achieved, accompanied by photoacoustic imaging capability.