Pt nanoenzyme decorated yolk-shell nanoplatform as an oxygen generator for enhanced multi-modality imaging-guided...

The unsatisfactory efficacy of conventional theranostic agents in ablating tumor poses urgent demands on the development of high-performance integrated theranostic agents utilizing rising nanotechnology. To cope with the existing limitations, here we presented an intelligent nanoplatform based on yolk-shell Fe₃O₄@polydopamine prepared by mussel-inspired polydopamine chemistry and sacrificial template method as well as subsequent incorporation of Pt nanoparticles and chlorine 6 (Ce6) by in situ reduction and electrostatic adsorption for photodynamic therapy (PDT) and photothermal (PTT). The resultant nanoplatform could effectively deliver photosensitizer Ce6 to tumor sites, then promoting the decomposition of endogenous H₂O₂ to oxygen, finally achieving enhanced PDT therapy, which is demonstrated by in vitro and in vivo evaluations. Importantly, the generated oxygen bubbles could improve the echogenicity signal of yolk-shell microspheres and thereby provide enhanced ultrasonic (US) signal for imaging solid tumors. Overall, the synergistic combination of magnetic Fe₃O₄, green polydopamine, catalytic Pt nanoparticles, photosensitive Ce6 enabled the hybrid nanoplatform to have good biocompatibility, efficient tumor accumulation, excellent phototherapy efficiency, high T₂-weighted magnetic resonance imaging (MRI) and fluorescence imaging ability (FL). Our study integrating the merits of PDT/PTT and US/MRI/FL into a single nanoplatform will open an avenue of therapeutic strategy toward biomedical applications.