Ultrasmall gold-encapsulated mesoporous platinum to promote photodynamic/catalytic therapy through cascade enzyme-like reactions

Mesoporous platinum (mPt) nanozyme possessed enzyme-like property of catalase (CAT) and peroxidase (POD), but the insufficient hydrogen peroxide (H₂O₂) concentration severely restricted its application in photodynamic therapy (PDT) and catalytic therapy. Herein, by depositing ultrasmall gold nanoparticles (AuNPs) and modifying photosensitizer IR808, a multifunctional nanozyme (mPt@Au-IR808) was designed to promote PDT/catalytic therapy through cascade enzyme-like reactions of glucose oxidase (GOx) and CAT/POD. In tumor microenvironment, the CAT-like oxygen (O₂) generation improved the PDT efficacy, and the POD-like hydroxyl radical (·OH) generation achieved endogenous catalytic therapy. Using the GOx/CAT-like activities and endogenous H₂O₂, the yields of singlet oxygen and ·OH were significantly promoted. Furthermore, mPt@Au-IR808 showed higher photothermal conversion efficiency (41.2%) than mPt (36.1%). By combining the photothermal therapy and enhanced PDT/catalytic therapy, the developed mPt@Au-IR808 nanozyme showed excellent anti-tumor efficacy, which will be promising as cascade nanozyme to promote photo/catalytic therapy.