Dual Nanozyme-Driven PtSn Bimetallic Nanoclusters for Metal-Enhanced Tumor Photothermal and Catalytic Therapy.

Specific generation of reactive oxygen species (ROS) within tumors catalyzed by nanozymes is a promising strategy for cancer therapeutics. However, it remains a significant challenge to fabricate highly efficient nanozymes acting in the tumor microenvironment. Herein, we develop a bimetallic nanozyme (PtSn) with the photothermal enhancement of dual enzymatic activities for tumor catalytic therapy. The structures and activities of PtSn bimetallic nanoclusters (BNCs) with different Sn content are explored and evaluated systematically. Experimental comparisons show that the PtSn BNCs exhibit the highest activities among all those investigated, including enzymatic activity and photothermal property, due to the generation of SnO with oxygen vacancy (O) sites on the surface of PtSn BNCs. Specifically, the PtSn BNCs exhibit photothermal-enhanced peroxidase-like and catalase-like activities, as well as a significantly enhanced anticancer efficacy in both multicellular tumor spheroids and experiments. Due to the high X-ray attenuation coefficient and excellent light absorption property, the PtSn BNCs also show dual-mode imaging capacity of computed tomography and photoacoustic imaging, which could achieve real-time monitoring of the therapeutic process. Therefore, this work will advance the development of noble-metal nanozymes with optimal composition for efficient tumor catalytic therapy.