Hypoxia-Activatable Nanovesicles as In Situ Bombers for Combined Hydrogen-Sulfide-Mediated Respiration Inhibition and Photothermal Therapy

Photothermal therapy (PTT) has emerged as a promising alternative or supplement to cancer treatments. While PTT induces the ablation of solid tumors, its efficiency is hampered by self-recovery within impaired cancer cells through glycolysis and respiration metabolism. Based on this, the introduction of hydrogen sulfide (H2S)-mediated respiration inhibition is a good choice to make up for the PTT limitation. Herein, nanovesicles (NP1) are integrated by a hypoxia-responsive conjugated polymer (P1), polymetric H2S donor (P2), and near-infrared (NIR) light-harvesting aza-BODIPY dye (B1) for the delivery of H2S and synergistic H2S gas therapy/PTT. The scaffold of NP1 undergoes disassembly in the hypoxic environments, thus triggering the hydrolysis of P2 to continuously long-term release H2S. Dependent on the superior photothermal ability of B1, NP1 elicits high photothermal conversion efficiency (eta = 19.9%) under NIR light irradiation for PTT. Moreover, NP1 serves as in situ H2S bombers in the hypoxic tumor environment and suppresses the mitochondrial respiration through inhibiting expression of cytochrome c oxidase (COX IV) and cutting off the adenosine triphosphate (ATP) generation. Both in vitro and in vivo results demonstrate good antitumor efficacy of H2S gas therapy/PTT, which will be recommended as an advanced strategy for cancer therapeutics.