School of Chemical Sciences, UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina, Santacruz (E), Mumbai 400098, India.
Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
ACS Appl Bio Mater. 2024 Nov 18;7(11):7207-7218. doi: 10.1021/acsabm.4c00804. Epub 2024 Oct 24.
Several reports are available on aggregation-induced emission and its applications in biomedical imaging and other material sciences. However, enhancement of singlet oxygen generation in nanoaggregates is rarely reported. Here, we report the synthesis of , which absorbs at 661 nm (monomer) with a high molar absorption coefficient. The presence of bromine promotes intersystem crossing, thereby enhancing the singlet oxygen quantum yield (Φ ∼ 0.50 in methanol). In order to increase hydrophilicity, we developed nanoaggregates (∼100 nm), which demonstrated aggregation-induced properties and exhibited a bathochromic shift with an absorption maximum at 757 nm. The bathochromic shift in the UV-vis spectra due to aggregation is corroborated by TD-DFT analysis. The computational data also confirm the presence of a low-lying triplet state, which enhances the generation of singlet oxygen, making it effective for photodynamic therapy. These aggregates showed excellent singlet oxygen generation in aqueous media, compared to their monomeric form and standard methylene blue. Their hydrophilic nature and high singlet oxygen generation enabled significant phototoxicity against human carcinoma cells with IC values of 4.06 ± 0.01 and 4.09 ± 0.1 μM, respectively, for MCF-7 and A549 cells upon 5 min exposure to light. Moreover, their phototoxicity further increases with an increasing exposure time of light for both cell lines. Notably, nanoaggregates exhibited nearly zero dark cell toxicity and effectively induced apoptosis in cancer cells upon light activation, highlighting their potential as powerful photosensitizers for photodynamic cancer therapy.
有几篇关于聚集诱导发光及其在生物医学成像和其他材料科学中的应用的报告。然而，纳米聚集体中单线态氧生成的增强很少有报道。在这里，我们报告了 的合成，其在 661nm 处吸收（单体），具有高摩尔消光系数。溴的存在促进了系间窜跃，从而提高了单线态氧量子产率（在甲醇中约为 0.50）。为了提高亲水性，我们开发了 纳米聚集体（约 100nm），它们表现出聚集诱导的性质，并表现出与吸收最大值为 757nm 的红移。由于聚集引起的紫外-可见光谱中的红移得到了 TD-DFT 分析的证实。计算数据还证实了存在低能三重态，这增强了单线态氧的生成，使其在光动力治疗中有效。与单体形式和标准亚甲蓝相比，这些聚集体在水介质中表现出优异的单线态氧生成能力。它们的亲水性和高单线态氧生成能力使它们对人癌细胞具有显著的光毒性，对 MCF-7 和 A549 细胞的 IC 值分别为 4.06±0.01 和 4.09±0.1μM，在 5 分钟的光照下。此外，随着两种细胞系光照时间的增加，其光毒性进一步增加。值得注意的是， 纳米聚集体在黑暗中几乎没有细胞毒性，并在光激活后有效地诱导癌细胞凋亡，突出了它们作为光动力癌症治疗的强大光敏剂的潜力。
