Nature Communications (Aug 2023)

Engineered NIR-II fluorophores with ultralong-distance molecular packing for high-contrast deep lesion identification

  • Zhe Feng,
  • Yuanyuan Li,
  • Siyi Chen,
  • Jin Li,
  • Tianxiang Wu,
  • Yanyun Ying,
  • Junyan Zheng,
  • Yuhuang Zhang,
  • Jianquan Zhang,
  • Xiaoxiao Fan,
  • Xiaoming Yu,
  • Dan Zhang,
  • Ben Zhong Tang,
  • Jun Qian

DOI
https://doi.org/10.1038/s41467-023-40728-6
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 14

Abstract

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Abstract The limited signal of long-wavelength near-infrared-II (NIR-II, 900–1880 nm) fluorophores and the strong background caused by the diffused photons make high-contrast fluorescence imaging in vivo with deep tissue disturbed still challenging. Here, we develop NIR-II fluorescent small molecules with aggregation-induced emission properties, high brightness, and maximal emission beyond 1200 nm by enhancing electron-donating ability and reducing the donor-acceptor (D-A) distance, to complement the scarce bright long-wavelength emissive organic dyes. The convincing single-crystal evidence of D-A-D molecular structure reveals the strong inhibition of the π-π stacking with ultralong molecular packing distance exceeding 8 Å. The delicately-designed nanofluorophores with bright fluorescent signals extending to 1900 nm match the background-suppressed imaging window, enabling the signal-to-background ratio of the tissue image to reach over 100 with the tissue thickness of ~4–6 mm. In addition, the intraluminal lesions with strong negatively stained can be identified with almost zero background. This method can provide new avenues for future long-wavelength NIR-II molecular design and biomedical imaging of deep and highly scattering tissues.