Scheme 1.

Schematic illustration showing a TPP-PPG@ICG nanocomposite targeting a mitochondrion for synergistic phototherapy with a single laser. The PS agent (ICG) was grafted onto the PEG- and BPEI-functionalized photothermal agent (NGO) to obtain TPP-PPG@ICG. After cellular internalization, TPP-PPG@ICG accumulated in mitochondria, induced mitochondria-related intrinsic apoptosis, surmounted drug resistance, and enhanced the antitumor efficacy after laser irradiation at 808 nm