Quinoid Conjugated Polymer Nanoparticles with NIR-II Absorption Peak Toward Efficient Photothermal Therapy

Recently, extensive efforts have been devoted to the development of the second near-infrared bio-window (NIR-II, 1000-1700 nm) theranostic agents owing to the excellent tissue-penetration capability of NIR-II light. The exploration of organic NIR-II photothermal therapy materials, especially those with absorption peak over 1000 nm, is an appealing yet significantly challenging task. Herein, we have designed conjugated polymer nanoparticles (PIS NPs) with NIR-II absorption peak at 1026 nm through a combined strategy of introducing quinoid donor-acceptor (D-A) structures, constructing intramolecular conformational locks and extending the conjugation area to narrow the band gap. Irradiated at 1064 nm, PIS NPs showed remarkable photothermal conversion performance for efficient photothermal ablation of tumor cells in vitro and in vivo. This study provides useful insights into the rational design of organic NIR-II photothermal agents based on multiple strategies.

Automated summary

Recently, there has been a focus on developing theranostic agents for the second near-infrared bio-window (NIR-II, 1000-1700 nm) due to its excellent tissue-penetration capabilities. In this study, conjugated polymer nanoparticles (PIS NPs) with a NIR-II absorption peak at 1026 nm were designed using a combination of strategies. Under irradiation at 1064 nm, PIS NPs demonstrated remarkable photothermal conversion performance for efficient ablation of tumor cells in vitro and in vivo. This research offers valuable insights into the rational design of organic NIR-II photothermal agents based on multiple strategies.