Semiconducting polymer dots (Pdots) have recently emerged as a new type of ultrabright fluorescent probe that has been proved to be very useful for biomedical imaging. However, Pdots often suffer from serious fluorescence aggregation-caused quenching (ACQ) especially for near-infrared (NIR) fluorescent Pdots. This article compared two strategies to overcome the ACQ effect in near-infrared emissive Pdot systems: aggregation-induced emission (AIE) and anti-aggregation-caused quenching (anti-ACQ). The results show that the anti-ACQ platform outperforms the AIE system. The fluorescence quantum yield of anti-ACQ-based Pdots can be over 50% and the average per-particle brightness of the Pdots is about 5 times higher than that of the commercially available quantum dots. To help understand why the monomer conformations could greatly affect the optical properties of Pdots, molecular dynamics simulations were performed for the first time in such complicated Pdot systems. To demonstrate applications for in vivo fluorescence imaging, both microangiography imaging on living zebrafish embryos and specific tumor targeting on mice were performed. We anticipate that these studies will pave the way for the design of new highly fluorescent Pdot systems.

中文翻译：

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用于肿瘤靶向的近红外荧光 Pdot 的分子设计：聚集诱导发射与抗聚集引起的猝灭†

半导体聚合物点（Pdot）最近作为一种新型超亮荧光探针出现，已被证明对于生物医学成像非常有用。然而，Pdot 经常遭受严重的荧光聚集引起的猝灭 (ACQ)，尤其是近红外 (NIR) 荧光 Pdot。本文比较了克服近红外发射 Pdot 系统中 ACQ 效应的两种策略：聚集诱导发射 (AIE) 和抗聚集引起的猝灭 (anti-ACQ)。结果表明，anti-ACQ 平台的性能优于 AIE 系统。基于抗ACQ的P点的荧光量子产率可以超过50％，并且P点的平均每颗粒亮度比市售量子点高约5倍。为了帮助理解为什么单体构象会极大地影响 Pdot 的光学性质，首次在如此复杂的 Pdot 系统中进行了分子动力学模拟。为了演示体内荧光成像的应用，对活体斑马鱼胚胎进行了微血管造影成像，并对小鼠进行了特定肿瘤靶向。我们预计这些研究将为新型高荧光 Pdot 系统的设计铺平道路。