Yolk-shell Fe3O4@Carbon@Platinum-Chlorin e6 nanozyme for MRI-assisted synergistic catalytic-photodynamic-photothermal tumor therapy

Tumor treatments based on phototherapy, such as photodynamic therapy (PDT) and photothermal therapy (PTT), are promising anticancer strategies. However, their dependence on light also poses several limitations for their application. Therefore, the establishment of a multifunctional nanotheranostic platform based on light therapy is needed to improve applicability of the technology.We designed yolk-shell magnetic Fe3O4@Carbon@Platinum-Chlorin e6 nanoparticles (MCPtCe6), which may be used for Magnetic resonance imaging (MRI) and synergistic catalytic-photodynamic-photothermal (catalytic-PDT-PTT) tumor therapy.We designed to compound multiple nanozymes and solve the drawbacks of single nanozyme and give additional functionalization to nanozymes for tumor therapy. Fe3O4 has T2 weighted MRI ability. The designed yolk-shell structure can disperse Fe3O4 in the carbon shell layer, which in turn can act as a carrier for PtNPs and improve the dispersion of both Fe3O4 and Pt. Pt nanoparticles attached to the surface of N-doped carbon spheres enhanced the catalytic ability of the nanozyme to generate reactive oxygen species (ROS). The covalently linked photosensitizer chlorin e6 (Ce6) on the Fe3O4@C@Pt (MCPt) nanozyme is essential for the therapeutic effects of PDT. MCPtCe6 can be specifically activated by the microenvironment through an enzyme-like catalytic process and extend PDT/PTT in acidic and H2O2-rich microenvironments. The results showed that MCPtCe6 had a high photothermal conversion efficiency (η = 28.28%), indicating its feasibility for PTT. Further cellular and animal studies have revealed that catalytic-PDT-PTT therapy can effectively inhibit tumors both in vitro and in vivo.