An activatable nanocomposite as a hydrogen peroxide-catalytic oxygenerator for tumor imaging and enhanced photodynamic therapy

Abstract

Photodynamic therapy has been used in the treatment of a variety of tumors, with a high degree of tumor inhibition and reduced side effects. However, the typically hypoxic micro-environment of tumor tissue has long been a key factor limiting the efficacy of tumor photodynamic therapy. Here, we designed and synthesized a nanocomposite RCDs@MnO2, which compounded red emissive carbon-dots (RCDs) with manganese dioxide nanosheets (MnO2), for catalyzes hydrogen peroxide (H2O2) to produce O2 to improve tumor hypoxic environment. The precursor of RCDs showing a wide absorption band in the visible to near-infrared region (400–800 nm) with red emission (from 500 to 800 nm, peaking at 640 nm). These prepared RCDs could produce 1O2 under 550 nm laser irradiation to achieve the purpose of photodynamic therapy. In addition, MnO2 could quench the fluorescence emission of RCDs and exhibit an RCDs@MnO2 fluorescence “off-on” function in tumor cells and tissues. RCDs@MnO2 could achieve the fluorescence imaging of tumor cells and tumor tissues, and improve the tumor hypoxic environment and enhance photodynamic treatment effect. RCDs@MnO2 has the powerful potential to be applied to fluorescence imaging of tumor tissue and significantly improve the photodynamic therapy of tumor, when investigated in vitro and in vivo.