Molecular Design of Conjugated Small Molecule Nanoparticles for Synergistically Enhanced PTT/PDT

• Main Authors: Wei Shao, Chuang Yang, Fangyuan Li, Jiahe Wu, Nan Wang, Qiang Ding, Jianqing Gao, Daishun Ling
• Format: Article
• Language: English
• Published: SpringerOpen 2020-07-01
• Series: Nano-Micro Letters
• Subjects: Molecular design; Isoindigo; Conjugated small molecule nanoparticles; Singlet–triplet energy gap; Synergistic PTT/PDT
• Online Access: http://link.springer.com/article/10.1007/s40820-020-00474-6
• ISSN: 2311-6706; 2150-5551

Abstract Simultaneous photothermal therapy (PTT) and photodynamic therapy (PDT) is beneficial for enhanced cancer therapy due to the synergistic effect. Conventional materials developed for synergistic PTT/PDT are generally multicomponent agents that need complicated preparation procedures and be activated by multiple laser sources. The emerging monocomponent diketopyrrolopyrrole (DPP)-based conjugated small molecular agents enable dual PTT/PDT under a single laser irradiation, but suffer from low singlet oxygen quantum yield, which severely restricts the therapeutic efficacy. Herein, we report acceptor-oriented molecular design of a donor–acceptor–donor (D–A–D) conjugated small molecule (IID-ThTPA)-based phototheranostic agent, with isoindigo (IID) as selective acceptor and triphenylamine (TPA) as donor. The strong D–A strength and narrow singlet–triplet energy gap endow IID-ThTPA nanoparticles (IID-ThTPA NPs) high mass extinction coefficient (18.2 L g−1 cm−1), competitive photothermal conversion efficiency (35.4%), and a dramatically enhanced singlet oxygen quantum yield (84.0%) comparing with previously reported monocomponent PTT/PDT agents. Such a high PTT/PDT performance of IID-ThTPA NPs achieved superior tumor cooperative eradicating capability in vitro and in vivo.