MnO2-coated porous Pt@CeO2 core–shell nanostructures for photoacoustic imaging-guided tri-modal cancer therapy

Abstract

We describe the synthesis of MnO₂-coated porous Pt@CeO₂ core–shell nanostructures (Pt@CeO₂@MnO₂) as a new theranostic nano-platform. The porous Pt cores endow the core–shell nanostructures with high photothermal conversion efficiency (80%) in the near-infrared region, allowing for photothermal therapy (PTT) and photoacoustic imaging (PA) of tumors. The combination of the Pt core and porous CeO₂ interlayer enhances the separation of photo-generated electrons and holes, which is beneficial for the generation of singlet oxygen. With the porous structures of the cores and interlayers, the Pt@CeO₂@MnO₂ nanostructures are further loaded with an anti-cancer drug (doxorubicin, DOX). The degradation of the MnO₂ shell in the tumor microenvironment (TME) can generate O₂ for enhanced photodynamic therapy (PDT) and simultaneously trigger DOX release. PA imaging shows good accumulation and retention of DOX-loaded Pt@CeO₂@MnO₂ in tumors, which guides precise laser irradiation to initiate combined PTT and PDT. The synergistic PTT/PDT/chemotherapy demonstrated by DOX-loaded Pt@CeO₂@MnO₂ yields remarkable therapeutic outcomes in vitro and in vivo. Taken together, our DOX-loaded Pt@CeO₂@MnO₂ provides a new avenue for designing high-performance nano-platforms for imaging and therapeutics.