Dai Xian-Yin, Song Qi, Zhou Wei-Lei, Liu Yu
School of Chemistry and Pharmaceutical Engineering, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, Shandong 271016, P. R. China.
College of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. China.
JACS Au. 2023 Dec 20;4(1):216-227. doi: 10.1021/jacsau.3c00642. eCollection 2024 Jan 22.
Aqueous supramolecular long-lived near-infrared (NIR) material is highly attractive but still remains great challenge. Herein, we report cucurbit[8]uril confinement-based secondary coassembly for achieving NIR phosphorescence energy transfer in water, which is fabricated from dicationic dodecyl-chain-bridged 4-(4-bromophenyl)-pyridine derivative (G), cucurbit[8]uril (CB[8]), and polyelectrolyte poly(4-styrene-sulfonic sodium) (PSS) via the hierarchical confinement strategy. As compared to the dumbbell-shaped G, the formation of unprecedented linear polypseudorotaxane G⊂CB[8] with nanofiber morphology engenders an emerging phosphorescent emission at 510 nm due to the macrocyclic confinement effect. Moreover, benefiting from the following secondary assembly confinement, such tight polypseudorotaxane G⊂CB[8] can further assemble with anionic polyelectrolyte PSS to yield uniform spherical nanoparticle, thereby significantly strengthening phosphorescence performance with an extended lifetime (i.e., 2.39 ms, c.f., 45.0 μs). Subsequently, the organic dye Rhodamine 800 serving as energy acceptor can be slightly doped into the polyelectrolyte assembly, which enables the occurrence of efficient phosphorescence energy transfer process with efficiency up to 80.1% at a high donor/acceptor ratio, and concurrently endows the final system with red-shifted and long-lived NIR emission (710 nm). Ultimately, the as-prepared assembly is successfully exploited as versatile imaging agent for NIR window labeling and detecting in living cells.
水性超分子长寿命近红外（NIR）材料极具吸引力，但仍面临巨大挑战。在此，我们报道了基于葫芦[8]脲限制的二次共组装，以实现水中的近红外磷光能量转移，该材料由双阳离子十二烷基链桥连的4-(4-溴苯基)-吡啶衍生物（G）、葫芦[8]脲（CB[8]）和聚电解质聚（4-苯乙烯磺酸钠）（PSS）通过分级限制策略制备而成。与哑铃状的G相比，具有纳米纤维形态的前所未有的线性聚准轮烷G⊂CB[8]的形成，由于大环限制效应，在510 nm处产生了新的磷光发射。此外，受益于随后的二次组装限制，这种紧密的聚准轮烷G⊂CB[8]可以进一步与阴离子聚电解质PSS组装，产生均匀的球形纳米颗粒，从而显著增强磷光性能，延长寿命（即2.39 ms，相比之下，为45.0 μs）。随后，可以将作为能量受体的有机染料罗丹明800少量掺杂到聚电解质组装体中，这使得在高供体/受体比下能够发生高效的磷光能量转移过程，效率高达80.1%，并同时赋予最终体系红移且长寿命的近红外发射（710 nm）。最终，所制备的组装体成功地被开发为用于活细胞近红外窗口标记和检测的多功能成像剂。
