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 (HO) 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 (O) 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 HO, 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.