Fu Hong-Guang, Shi Xin-Xin, Liu Min, Wang Hui-Juan, Zhang Fanjun, Chen Yong, Liu Yu
College of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, (Tianjin), Nankai University, Tianjin 300071, P. R. China.
School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China.
ACS Appl Mater Interfaces. 2023 Oct 18;15(41):48564-48573. doi: 10.1021/acsami.3c12242. Epub 2023 Oct 4.
Supramolecular luminescent material with switchable behavior and photo-induced aggregation with emission enhancement is a current research hot spot. Herein, a size-tunable nano-supramolecular assembly with reversible photoluminescent behavior was constructed by noncovalent polymerization of diarylethene-bridged bis(coumarin) derivative (DAE-CO), cucurbit[7]uril (CB[7]), and β-cyclodextrin-grafted hyaluronic acid (HACD). Benefiting from the macrocyclic confinement effect, the guest molecule DAE-CO was included into the cavity of CB[7] to give enhanced fluorescence emission of the resulting DAE-CO⊂CB[7] with longer lifetime at 432 nm to 1.43 ns, thereby further enhancing fluorescence output and lifetime (1.46 ns) when further assembled with HACD, compared with the free DAE-CO (0.95 ns). In addition, DAE-CO, DAE-CO⊂CB[7], and DAE-CO⊂CB[7]&HACD all possessed characteristics of aggregation-induced emission and reversible photo-switched structural interconversion, exhibiting an obvious photophysical activation phenomenon of self-aggregation into larger nanoparticles with increase in fluorescence emission intensity, lifetime, and size after irradiation, which could be increased step by step with the alternating irradiation of 254 nm (5 min) or >600 nm (30 s) repeated 7 times. These supramolecular assemblies were successfully used in the tumor cells' targeted imaging and anti-counterfeiting because of the capability of HACD for recognizing specific receptors overexpressed on the surface of tumor cells and the excellent photo-regulated switch ability of DAE-CO, providing an approach of constructing photo-induced emission-enhanced luminescent materials.
具有可切换行为和光诱导聚集且发光增强的超分子发光材料是当前的研究热点。在此，通过二芳基乙烯桥联双（香豆素）衍生物（DAE-CO）、葫芦[7]脲（CB[7]）和β-环糊精接枝透明质酸（HACD）的非共价聚合构建了一种具有可逆光致发光行为的尺寸可调纳米超分子组装体。得益于大环限域效应，客体分子DAE-CO被纳入CB[7]的空腔中，使得所得的DAE-CO⊂CB[7]荧光发射增强，在432 nm处的寿命延长至1.43 ns，因此与游离的DAE-CO（0.95 ns）相比，当与HACD进一步组装时，荧光输出和寿命（1.46 ns）进一步增强。此外，DAE-CO、DAE-CO⊂CB[7]和DAE-CO⊂CB[7]&HACD均具有聚集诱导发光和可逆光开关结构互变的特性，表现出明显的光物理活化现象，即照射后自聚集形成更大的纳米颗粒，荧光发射强度、寿命和尺寸增加，通过254 nm（5分钟）或>600 nm（30秒）交替照射7次可逐步增强。由于HACD能够识别肿瘤细胞表面过表达的特异性受体以及DAE-CO出色的光调控开关能力，这些超分子组装体成功用于肿瘤细胞的靶向成像和防伪，为构建光诱导发射增强的发光材料提供了一种方法。
