Materials Chemistry

Rational Design of NIR-II AIEgens with Ultrahigh Quantum Yields for Photo- and Chemiluminescence Imaging

Authors

  • Hanchen Shen Hong Kong University of Science and Technology - China ,
  • Feiyi Sun Hong Kong University of Science and Technology - China ,
  • Xinyan Zhu Fudan University ,
  • Jianyu Zhang Hong Kong University of Science and Technology - China ,
  • Xinwen Ou Hong Kong University of Science and Technology - China ,
  • Jianquan Zhang Hong Kong University of Science and Technology - China ,
  • Changhuo Xu Hong Kong University of Science and Technology - China ,
  • Herman H. Y. Sung Hong Kong University of Science and Technology - China ,
  • Ian D. Williams Hong Kong University of Science and Technology - China ,
  • Sijie Chen Karolinska Institutet in Hong Kong - China ,
  • Ryan T. K. Kwok Hong Kong University of Science and Technology - China ,
  • Jacky W. Y. Lam Hong Kong University of Science and Technology - China ,
  • Jianwei Sun Hong Kong University of Science and Technology - China ,
  • Fan Zhang Fudan University ,
  • Ben Zhong Tang Chinese University of Hong Kong, Shenzhen & Hong Kong University of Science and Technology - China & Karolinska Institutet in Hong Kong - China & South China University of Technology - China

Abstract

Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1700 nm) using small-molecule dyes is highly potential for clinical use. However, many NIR-II dyes suffer from the emission quenching effect and extremely low quantum yields (QYs) in the practical usage forms. The AIE strategy has been successfully utilized to develop NIR-II dyes with donor-acceptor (D-A) structures with acceptable QYs in the aggregate state, but there is still a large room for QY improvement. Here, we rationally designed NIR-II emissive dye named TPE-BBT and its derivative (TPEO-BBT) by changing the electron-donating triphenylamine unit to tetraphenylethlene (TPE). Their nanoparticles exhibited ultrahigh relative QYs of 31.5% and 23.9% in water, respectively. By using an integrating sphere, the absolute QY of TPE-BBT nanoparticles was measured to be 1.8% in water. Its crystals showed an absolute QY of 10.4%, which is the highest value among organ-ic small molecules reported so far. The optimized D-A interaction and the higher rigidity of TPE-BBT in the aggregate state are believed to be the two key factors for its ultrahigh QY. Finally, we utilized TPE-BBT for NIR-II photoluminescence (PL) and chemiluminescence (CL) bioimaging through successive CL resonance energy transfer and Förster resonance energy transfer processes. The ultrahigh QY of TPE-BBT realized an excellent PL imaging quality in mouse blood vessels, and an excellent CL imaging quality in the local arthrosis inflammation in mice with a high signal-to-background ratio of 130. Thus, the design strategy presented here brings new possibilities for the development of bright NIR-II dyes and NIR-II bioimaging technologies.

Content

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