Visual dual chemodynamic/photothermal therapeutic nanoplatform based on superoxide dismutase plus Prussian blue

Enzyme-based anticancer therapy is more attractive for the less side effect than conventional chemotherapy. However, the poor stability and low membrane permeability of enzymes during the intracellular delivery are constraints for its practical applications. In this work, we synthesized novel near-infrared (NIR)-responsive core–shell-structured Prussian blue@fibrous SiO₂ (PBFS) nanoparticles as the carrier of superoxide dismutase (SOD) and a glutathione (GSH)-activated Fenton reagent (DiFe). The PBFS nanoparticles are further modified with a GSH-responsive cationic polymer (poly(2-(acryloyloxy)-N, N-dimethyl-N-(4-(((2-((2-(((4-methyl-2-oxo-2H-chromen-7-yl)carbamoyl)oxy)ethyl)disulfaneyl)ethoxy)carbonyl)amino)benzyl)ethan-1-aminium, PSS) containing disulfide bonds and fluorophores. After SOD and DiFe are loaded on the PBFS-PSS nanoparticles, dual chemodynamic/photothermal therapeutic nanoparticulate systems (PBFS-PSS/DiFe/SOD) are obtained. In vitro experiments show that PBFS-PSS/DiFe/SOD nanoparticles have good biocompatibility and can be tracked under fluorescence microscope during the intracellular delivery process in MCF-7 tumor cells due to the GSH-activated release of fluorophores. They also exhibit high efficiency in NIR photothermal conversion and GSH-activated Fenton reaction in tumor cells, thus achieving high-efficient killing effect of tumor cells based on the combination of photothermal and chemodynamic therapeutic performance (PTT and CDT). This work offers a novel pathway to construct a visual multifunctional nanomedicine platform for future cancer therapy.