Uncommon Supramolecular Phosphorescence‐Capturing Assembly Based on Cucurbit[8]uril‐Mediated Molecular Folding for Near‐Infrared Lysosome Imaging

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2022-01, Vol.18 (1), p.e2104514-n/a
• Main Authors: Huo, Man, Dai, Xian‐Yin, Liu, Yu
• Format: Article
• Language: English
• Subjects: amphiphilic calixarene; Bridged-Ring Compounds; Calixarenes; cucurbituril; delayed near‐infrared fluorescence; Imidazoles; lysosome imaging; Lysosomes; phosphorescence‐capturing assembly
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202104514

The construction of highly effective phosphorescence energy transfer capturing system still remains great challenge in aqueous phase. Herein, a high‐efficiency supramolecular purely organic room temperature phosphorescence (RTP)‐capturing system via a secondary assembly strategy by taking advantage of cucurbit[8]uril (CB[8]) and amphiphilic calixarene (SC4AH) is reported. Comparing with free bromonaphthalene‐connected methoxyphenyl pyridinium salt (G), G⊂CB[8] exhibits an emerging RTP emission peak at 530 nm. Moreover, G⊂CB[8] further interacts with SC4AH to form the ternary assembly G⊂CB[8]  @  SC4AH accompanied by remarkably enhanced RTP emission. Interestingly, RTP‐capturing systems with delayed near‐infrared (NIR) emissive performance (635, 675 nm) are feasibly acquired by introducing Nile Red (NiR) or Nile Blue (NiB) as the acceptor into hydrophobic layer of G⊂CB[8] @ SC4AH, possessing ultrahigh antenna effects (352.9, 123.5) at a high donor/acceptor ratio (150:1, 300:1). More importantly, cell experiments indicate that G⊂CB[8]  @  SC4AH/NiB not only hold low cytotoxicity but also can successfully realize NIR lysosome‐targeted imaging of A549 cancer cells. This RTP‐capturing system of delayed NIR emission via multistage assembly strategy offers a new approach for NIR imaging in living cells. A high‐efficiency supramolecular phosphorescence‐capturing system with delayed near‐infrared emission is successfully constructed via an efficient triplet to singlet Förster resonance energy transfer strategy, presenting ultrahigh antenna effects (352.9, 123.5) at a high donor/acceptor ratio (150:1, 300:1).