Structural modification of NIR-II fluorophores for angiography beyond 1300 nm: Expanding the xanthene universe

Chuangli Zhang, Jusung An, Jiasheng Wu, Weimin Liu, Hyeonji Rha, Jong Seung Kim, Pengfei Wang

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Fluorescence bioimaging via the second near-infrared (NIR-II) window can provide precise images with a low background signal due to attenuated absorption and scattering in biological tissues. However, it is challenging to realize organic fluorophores' absorption/emission wavelength beyond 1300 nm depending on their intrinsic emission of monomers. Reducing parasitic aggregation caused quenching (ACQ) effect is expected as an efficient strategy to achieve fluorescence bioimaging in an ideal region. Herein, two NIR-II xanthene fluorophores (CM1 and CM2) with different side chains on identical skeletons were synthesized. Besides, their corresponding assemblies (CM1 NPs and CM2 NPs) were subsequently prepared, which exhibited distinct spectroscopic properties. Notably, CM2 NPs exhibited a significantly reduced ACQ effect with maximal absorption/emission extended to 1235/1250 nm. Molecular dynamics simulations revealed that intermolecular hydrogen bond, π-π interaction, and CH-π interaction of CM2 were essential for the reduced ACQ effect. In vivo hindlimb angiography showed that CM2 NPs could distinguish the neighboring artery and vein in high resolution. Besides, CM2 NPs could achieve angiography beyond 1300 nm and even resolve capillaries as small as 0.23 mm. This study provides a new strategy for reducing the ACQ effect by controlling different side chains of NIR-II xanthene dyes for angiography beyond 1300 nm.

Original languageEnglish
Article number114701
JournalBiosensors and Bioelectronics
Publication statusPublished - 2022 Dec 1

Bibliographical note

Funding Information:
This work was supported by the National Natural Science Foundation of China (Grant Nos. 21873110 and 61720106014 ), the Instrument Developing Project of the Chinese Academy of Sciences (No. YJKYYQ20170015 ), and the National Research Foundation of Korea (CRI project no. 2018R1A3B1052702 , NRF-2019M3E5D1A01068998 , J. S. Kim). NIR-II fluorescence imaging in vivo of this work were conducted in Suzhou NIR-Optics Technology Co., Ltd., and we are grateful for their friendly support to this work.

Publisher Copyright:
© 2022 Elsevier B.V.


  • Angiography
  • NIR-II fluorescence Imaging
  • Reduced ACQ effect
  • Xanthene derivatives

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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