Multifunctional Mesoporous Hollow Cobalt Sulfide Nanoreactors for Synergistic Chemodynamic/Photodynamic/Photothermal Therapy with Enhanced Efficacy

The unique tumor microenvironment (TME) characteristic of severe hypoxia, overexpressed intracellular glutathione (GSH), and elevated hydrogen peroxide (H2O2) concentration limit the anticancer effect by monotherapy. In this report, glucose oxidase (GOx)-encapsulated mesoporous hollow Co9S8 nanoreactors are constructed with the coverage of polyphenol diblock polymers containing poly(oligo(ethylene glycol) methacrylate) and dopamine moieties containing methacrylate polymeric block, which are termed as GOx@PCoS. After intravenous injection, tumor accumulation, and cellular uptake, GOx@PCoS deplete GSH by Co3+ ions. GOx inside the nanoreactors produce H2O2 via oxidation of glucose to enhance •OH-based chemodynamic therapy (CDT) through the Fenton-like reaction under the catalysis of Co2+. Moreover, Co3+ ions possess catalase activity to catalyze production of O2 from H2O2 to relieve tumor hypoxia. Upon 808 nm laser irradiation, GOx@PCoS exhibit photothermal and photodynamic effects with a high photothermal conversion efficiency (45.06%) and generation capacity of the toxic superoxide anion (•O2-) for photothermal therapy (PTT) and photodynamic therapy (PDT). The synergetic antitumor effects can be realized by GSH depletion, starvation, and combined CDT, PTT, and PDT with enhanced efficacy. Notably, GOx@PCoS can also be used as a magnetic resonance imaging (MRI) contrast agent to monitor the antitumor performance. Thus, GOx@PCoS show great potentials to effectively modulate TME and perform synergistic multimodal therapy.