Development of novel near-infrared photothermal material for efficient breast cancer therapy

Photothermal therapy (PTT) has become a candidate treatment for breast cancer due to its non-invasive, specific and controllable properties. However, there are few strategies to develop photothermal agents with high photothermal conversion efficiency, adequate tumor accumulation, and the molecular design theory is not perfect. Thus, to obtain the photothermal agent with better comprehensive performance, a novel conjugated polymer PAPQ-Th, comprising quinoxaline derivative 10,11-bis(4-(octyloxy) phenyl)acenaphtho[1,2-b]pyrazino[2,3-g]quinoxaline (PAPQ) as the acceptor and thiophene (Th) as the donor, was designed and synthesized. The PAPQ-Th exhibited the high non-radiative rate of 7.3 × 1011 s−1 and faint fluorescence emission. And PAPQ-Th nanoparticles exhibited strong NIR absorption from 650 nm to 900 nm, negligible ROS generation, and an impressively high photothermal conversion efficiency of 61 % under an 808 nm laser irradiation. Furthermore, PAPQ-Th nanoparticles can be successfully used for both in vitro and in vivo experiments, and exhibited remarkable photothermal antitumor efficacy. After intravenous administration and 808 nm laser irradiation, 4T1 tumor-bearing mice achieve complete tumor remission without recurrence. The results demonstrate that the design of new quinoxaline derivative and construction of novel donor-acceptor conjugated polymer are the effective strategy for the synthesis of efficient photothermal agent. A novel near-infrared photothermal material for efficient breast cancer therapy was developed. [Display omitted] •A novel near-infrared photothermal material (PAPQ-Th) for efficient breast cancer therapy was developed.•The PAPQ-Th exhibited the high non-radiative rate of 7.3 × 1011 s−1 and faint fluorescence emission.•The PAPQ-Th nanoparticles exhibited strong NIR absorption from 650 nm to 900 nm and negligible ROS generation.•The PAPQ-Th nanoparticles an impressively high photothermal conversion efficiency of 61 % under an 808 nm laser irradiation.•The PAPQ-Th nanoparticles can be successfully used for both in vitro and in vivo experiments.