Biodegradable Charge-Transfer Complexes for Glutathione Depletion Induced Ferroptosis and NIR-II Photoacoustic Imaging Guided Cancer Photothermal Therapy.

Suffering from the laborious synthesis and undesirable tumor microenvironment response, the exploitation of novel NIR-II absorbing organic photothermal agents is of importance to promote phototherapeutic efficacy. Herein, two kinds of charge-transfer complex nanoparticles (TMB-F4TCNQ and TMB-TCNQ) are prepared by supramolecular assembly. Because of the larger energy gap between donor and acceptor, TMB-F4TCNQ presents higher charge-transfer degree (72 %) than that of TMB-TCNQ (48 %) in nanoaggregates. Therefore, TMB-F4TCNQ exhibits stronger NIR-II absorption ability with a mass extinction coefficient of 15.4 Lg-1  cm-1 at 1300 nm and excellent photothermal effect. Impressively, the specific cysteine response can make the TMB-F4TCNQ effectively inhibit the intracellular biosynthesis of GSH, leading to redox dsyhomeostasis and ROS-mediated ferroptosis. TMB-F4TCNQ can serve as a contrast agent for NIR-II photoacoustic imaging to guide precise and efficient photothermal therapy in vivo.