Acceptor motor-driven electronic donor-acceptor supramolecular scaffold towards imaging-guided tumor therapy

Abstract

The traditional approaches access to near infrared (NIR) photothermal agents mainly focus on synthesis. Herein, based on a supramolecular strategy, an electrostatic force-driven electronic donor-acceptor complex is established with 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HAT-CN) and perylene as acceptor and donor, respectively. Due to a strong electronic affinity of the acceptor and the opposite electronic property between them, a through-space charge transfer forms in the assembly to remarkably narrow the energy gap to induce an obvious NIR absorption and benefit the photothermal conversion. More interestingly, the bond stretching vibration is dramatic and sufficient in the acceptor, enabling it as an acceptor motor in the supramolecular complex to further enhance the photothermal property. As a result, a prompt heating effect by more than 190 °C can be obtained in the powder under 808 nm laser excitation and the photothermal conversion efficiency of the nanoparticles (NPs) is recorded as high as 59.4%. Thanks to the good photothermal effect, the in vitro and in vivo photoacoustic (PA) imaging can be well performed with the NPs. Moreover, the NPs display a prominent phototoxicity to kill the CT26 cells and ablate the tumor in the living mice with the photothermal immunomodulatory effect evoked concurrently. The synergetic strategy in this work paves a facile, economic and flexible avenue for designing the highly efficient NIR photothermal agents to accelerate the practical biomedical application.