A traceable nanoplatform for enhanced chemo-photodynamic therapy by reducing oxygen consumption.

Tumor hypoxia impedes the efficiencies of oxygen-dependent photodynamic therapy (PDT) and chemotherapy. Herein, we design a traceable nanoplatform (DOX/Met/BSA-HA-CDs) by reducing oxygen (O2) consumption to overcome the hypoxia-caused cancer therapy. Carbon dots (CDs) are used not only as a PDT agent but also applied for in vivo traceable imaging. Metformin (Met), a potent antihyperglycemic agent, to improve tumor oxygenation and enhance the efficiencies of hypoxia-caused cancer therapy. In the hypoxic tumor microenvironment, Met was released more rapidly than DOX, which is advantageous for improving hypoxic cancer to exert a better therapeutic efficiency. Ex vivo immunofluorescence staining revealed that the DOX/Met/BSA-HA-CDs nanoparticles greatly reduce O2 consumption in tumor site. Followed by in vivo synergistic treatment achieved considerably enhanced cancer therapeutic efficiency. This system holds great clinical promise as a traceable imaging approach to guide the improvement of PDT and chemotherapy efficiencies through utilizing a simple, safe method improved hypoxic tumor microenvironment.