Liu Diankai, He Zixu, Gao Wenjie, Shang Jizhen, Yang Yiqing, Zhang Xiaofan, Li Xiaohua, Ma Huimin, Shi Wen
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Nat Commun. 2025 May 27;16(1):4911. doi: 10.1038/s41467-025-60241-2.
Fluorescence bioimaging in the near-infrared II window is a promising area due to its deep tissue penetration and high contrast. However, efficient design strategies for near-infrared II fluorophores with large Stokes shifts are still scarce. Here, we develop a series of near-infrared II fluorophores (termed VIPIs) with large Stokes shifts (167-260 nm in chloroform) by conjugating p-aminostyryl to hemicyanines. Time dependent density functional theory calculation and transient absorption spectra reveal that the excitation process is predominantly localized within the cyanine moiety, whereas the emission process involves the charge transfer from the cyanine to styryl moiety. We demonstrate the applications of VIPIs in multicolor imaging and conjugatable modification. Finally, we show that VIPI-4 liposomes can image the fine bone structure of knee joint of female mice over 1300 nm. This work provides insights into the excited-state photophysical processes in near-infrared II window, offering inspiration for designing fluorophores with extended emission and large Stokes shifts.
近红外二区窗口的荧光生物成像因其深层组织穿透能力和高对比度而成为一个有前景的领域。然而，具有大斯托克斯位移的近红外二区荧光团的有效设计策略仍然匮乏。在此，我们通过将对氨基苯乙烯基与半菁共轭，开发了一系列具有大斯托克斯位移（在氯仿中为167 - 260纳米）的近红外二区荧光团（称为VIPIs）。含时密度泛函理论计算和瞬态吸收光谱表明，激发过程主要局限于菁部分，而发射过程涉及电荷从菁部分转移到苯乙烯基部分。我们展示了VIPIs在多色成像和可共轭修饰方面的应用。最后，我们表明VIPI - 4脂质体能够对超过1300纳米的雌性小鼠膝关节精细骨结构进行成像。这项工作为近红外二区窗口的激发态光物理过程提供了见解，为设计具有延长发射和大斯托克斯位移的荧光团提供了灵感。
