College of Chemistry and Chemical Engineering, Inner Mongolia Key Laboratory of Fine Organic Synthesis, Inner Mongolia University, Hohhot 010021, China.
Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research, Center for Tissue Restoration and Reconstruction, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China.
ACS Nano. 2024 Oct 15;18(41):28178-28188. doi: 10.1021/acsnano.4c07896. Epub 2024 Oct 3.
Conjugated polymers are becoming popular near-infrared II (NIR-II) phototheranostic agents (PTAs) due to their numerous advantages, such as high photostability, large molar extinction coefficients, and excellent photothermal properties. However, the strong π-π interactions between the chains of the conjugated polymers resulted in their generally low NIR-II emission quantum yields (QY). Therefore, the synthesis of conjugated polymers with high QY is an interesting but challenging task. Herein, we proposed a spacer twisting strategy to realize ultrabright NIR-II polymer nanoparticles for fluorescence imaging-guided tumor phototheranostics. Theoretical calculations indicated that the polymer PY-IT has the largest dihedral angle between the largely π-conjugated skeleton and the spacer, which can effectively inhibit intermolecular π-π stacking, resulting in an improved QY as high as 16.5% in nanoparticles. In addition, PY-IT NPs can effectively perform NIR-II imaging and photothermal treatment of tumors. The work presents some valuable guides for achieving ultrabright NIR-II polymeric PTAs with high QY.
共轭聚合物由于其众多优点，如高光稳定性、大摩尔消光系数和优异的光热性能，正在成为热门的近红外二区（NIR-II）光热治疗剂（PTAs）。然而，共轭聚合物链之间的强π-π相互作用导致其通常具有低的近红外二区发射量子产率（QY）。因此，合成具有高 QY 的共轭聚合物是一项有趣但具有挑战性的任务。在这里，我们提出了一种间隔物扭曲策略，以实现用于荧光成像引导的肿瘤光热治疗的超高亮近红外二区聚合物纳米粒子。理论计算表明，聚合物 PY-IT 在大的π共轭骨架和间隔物之间具有最大的二面角，这可以有效地抑制分子间π-π堆积，从而使纳米粒子中的 QY 提高到高达 16.5%。此外，PY-IT NPs 可以有效地进行近红外二区成像和肿瘤光热治疗。这项工作为实现具有高 QY 的超高亮近红外二区聚合物 PTA 提供了一些有价值的指导。
