近日，南京邮电大学胡文博团队通过操纵二聚体群体来减轻环融合荧光团中的NIR-II发射淬灭，以实现卓越的荧光成像。相关论文于2025年3月4日发表在《光：科学应用》杂志上。

荧光团聚集导致的发射淬灭长期以来一直是优化基于发射的技术（如荧光成像和光电器件）的一个重大挑战。缓解骨料中的这种淬灭至关重要，但由于对骨料的性质和对排放的影响了解有限，进展受到阻碍。

研究组阐明了二聚体聚集体（二聚体）在缓解环融合荧光团4F的第二近红外（NIR-II，900-1700nm）发射淬灭中的关键作用，以实现卓越的荧光成像。光谱分解和分子动力学模拟证明了4F聚集体中二聚体群体的优势。值得注意的是，与单体相比，二聚体的发射明显较弱，但分子间非辐射（interNR）衰变强烈，如超快光谱和量子计算所示。因此，具有弱发射和明显interNR特征的二聚体的主要群体是4F聚集体发射淬灭的基础。

这一发现通过减少二聚体群体来指导超亮NIR-II 4F纳米荧光团（4F NP3s）的制备，二聚体的NIR-II亮度比吲哚青绿高5倍，从而在可视化血管方面具有更高的分辨率。这项工作为聚集引起的淬灭提供了宝贵的见解，其广泛的影响远远超出了NIR-II荧光成像。

附：英文原文

Title: Alleviating NIR-II emission quenching in ring-fused fluorophore via manipulating dimer populations for superior fluorescence imaging

Author: Miao, Xiaofei, Jia, Mingxuan, Weng, Xianwei, Zhang, Jie, Pan, Yonghui, Zhao, Hui, Yu, Zhongzheng, Fan, Quli, Hu, Wenbo

Issue&Volume: 2025-03-04

Abstract: Emission quenching resulting from fluorophore aggregation has long been a significant challenge in optimizing emission-based technologies, such as fluorescence imaging and optoelectronic devices. Alleviating this quenching in aggregates is crucial, yet progress is impeded by the limited understanding of the nature and impact of aggregates on emission. Here, we elucidate the critical role of dimeric aggregate (dimer) in alleviating second near-infrared (NIR-II, 900-1700nm) emission quenching from ring-fused fluorophore 4F for superior fluorescence imaging. Spectral decomposition and molecular dynamics simulations demonstrate the predominance of dimer populations in 4F aggregates. Notably, dimers exhibit significantly weaker emission but intense intermolecular nonradiative (interNR) decay compared to monomers, as demonstrated by ultrafast spectra and quantum calculation. Therefore, the predominant population of dimers with weak emission and pronounced interNR feature underlies the emission quenching in 4F aggregates. This discovery guides the preparation of ultrabright NIR-II 4F nanofluorophore (4F NP3s) by decreasing dimer populations, which show 5-fold greater NIR-II brightness than indocyanine green, enabling superior resolution in visualizing blood vessels. This work offers valuable insights into aggregation-caused quenching, with broad implications extending far beyond NIR-II fluorescence imaging.

DOI: 10.1038/s41377-025-01787-0

Source: https://www.nature.com/articles/s41377-025-01787-0