Scheme 1.

Schematic illustration of nanocarriers exerting therapeutic effects in vivo. After administration, the drug-loaded photothermal nanocarriers navigate to tumors through the blood circulation. Owing to the enhanced permeability and retention (EPR) effects, the nanocarriers penetrate tumor tissues across vessel walls of tumor vasculature, leading to accumulation within tumors. The nanocarriers then enter tumor cells via endocytosis. If targeting ligands exist, the endocytosis may be enhanced. After entrance into cells, the nanocarriers release drugs and emit heat under NIR radiation, leading to synergistic effects of CHT and PTT.