School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India.
Advanced Instrument Research Facility, Jawaharlal Nehru University, New Delhi, India.
Sci Rep. 2018 Jun 19;8(1):9322. doi: 10.1038/s41598-018-27246-y.
Herein, we report a facile microwave-assisted synthesis of cadmium-free water-soluble silver indium sulfide (AgInS or AIS) and AgInS@ZnS (or AIS@ZnS) core-shell quantum dots (QDs) using glutathione (GSH) as stabilizer. The core and core-shell nanocrystals exhibit tunable bandgap ranging of 2.3-3.1 and 2.4-3.5 eV, mean particle size of 2.5 and 3.25 nm, quantum yield of 26% and 49%, and fluorescence lifetimes of 326 and 438 ns, respectively. The core-shell QDs exhibit color-tunable emission in the visible region (500 to 600 nm), where the tunability was achieved by varying the molar ratio of Ag:In in the precursors. In vitro evaluation of antifungal activity of these water/ buffer stable QDs against the fungal pathogen, Candida albicans demonstrated that these were not toxic to the fungal cells upto a concentration of 100 µg/ml for 16 hours of incubation. Confocal imaging and spectrofluorometric studies showed enhanced fluorescence inside the microbial cells suggesting that AIS@ZnS particles had the capability to easily penetrate the cells. The increased generation of reactive oxygen species was evaluated for the core-shell QDs (photosensitizers) by using 9, 10-anthracenediyl-bis(methylene)dimalonic acid (ABMDMA) as singlet oxygen (O) scavenger molecule. These QDs have the potential for use as high contrast cell imaging, photodynamic and antifungal agents.
在此，我们报告了一种使用谷胱甘肽 (GSH) 作为稳定剂，通过简便的微波辅助法合成无镉水溶性银铟硫 (AgInS 或 AIS) 和 AgInS@ZnS（或 AIS@ZnS）核壳量子点 (QD) 的方法。核和核壳纳米晶体具有可调带隙，范围为 2.3-3.1 和 2.4-3.5 eV，平均粒径为 2.5 和 3.25 nm，量子产率为 26%和 49%，荧光寿命分别为 326 和 438 ns。核壳 QD 在可见区（500 至 600 nm）表现出可调谐的发射颜色，通过改变前驱体中 Ag:In 的摩尔比可以实现调谐。这些水/缓冲液稳定的 QD 对真菌病原体白色念珠菌的体外抗真菌活性评估表明，这些 QD 在 16 小时孵育时间内，浓度高达 100 μg/ml 时对真菌细胞没有毒性。共聚焦成像和荧光光谱研究表明，在微生物细胞内荧光增强，表明 AIS@ZnS 颗粒具有穿透细胞的能力。通过使用 9,10-蒽二亚基-双（亚甲基）二马来酸（ABMDMA）作为单线态氧 (O) 清除剂分子，评估了核壳 QD（光敏剂）中活性氧的产生。这些 QD 具有作为高对比度细胞成像、光动力和抗真菌剂的潜力。
