Super-stable cyanine@albumin fluorophore for enhanced NIR-II bioimaging

作者：Bai, Lang; Hu, Zhubin; Han, Tianyang; Wang, Yajun; Xu, Jiajun; Jiang, Guanyu; Feng, Xin; Sun, Bin; Liu, Xiangping; Tian, Rui^*; Sun, Haitao^*; Zhang, Songling; Chen, Xiaoyuan^*; Zhu, Shoujun^*

来源：2022, 12(10): 4536-4547.

DOI：10.7150/thno.71443

• NIR-II imaging
• cyanine dye
• albumin
• super-stable NIR-II probe
• covalent bond

Near-infrared-II (NIR-II) dyes could be encapsulated by either exogenous or endogenous albumin to form stable complexes for deep tissue bioimaging. However, we still lack a complete understanding of the interaction mechanism of the dye@albumin complex. Studying this principle is essential to guide efficient dye synthesis and develop NIR-II probes with improved brightness, photostability, etc. @@@ Methods: Here, we screen and test the optical and chemical properties of dye@albumin fluorophores, and systematically investigate the binding sites and the relationship between dye structures and binding degree. Super-stable cyanine dye@albumin fluorophores are rationally obtained, and we also evaluate their pharmacokinetics and long-lasting NIR-II imaging abilities. @@@ Results: We identify several key parameters of cyanine dyes governing the supramolecular/covalent binding to albumin, including a six-membered ring with chlorine (CI), the small size of side groups, and relatively high hydrophobicity. The tailored fluorophore (IR-780@albumin) exhibits much-improved photostability, serving as a long-lasting imaging probe for NIR-II bioimaging. @@@ Conclusion: Our study reveals that the chloride-containing cyanine dyes with the above-screened chemical structure (e.g. IR-780) could be lodged into albumin more efficiently, producing a much more stable fluorescent probe. Our finding partly solves the photobleaching issue of clinically-available cyanine dyes, enriching the probe library for NIR-II bioimaging and imaging-guided surgery.

• 单位
  吉林大学; 厦门大学