Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon S7N 5C9, Canada.
Langmuir. 2021 Nov 16;37(45):13471-13478. doi: 10.1021/acs.langmuir.1c02225. Epub 2021 Nov 5.
An improved and simple synthetic method for producing stable narrow-sized glycine-cystamine (Gly-CSA)-functionalized Au nanoclusters (NCs) from protected Fmoc-glycine-cystamine (Fmoc-Gly-CSA)-functionalized Au NCs is demonstrated in this study. The NC size and size distribution can be controlled directly as a function of reducing agent concentration with the formation of smaller NC core diameters at higher concentrations of NaBH. Furthermore, when using 0.30 M NaBH, three UV-vis absorption peaks at 690, 440, and 390 nm were seen, which are consistent with the formation of Fmoc-Gly-CSA-functionalized AuL NCs. After deprotection of the Gly-CSA-functionalized Au NCs, the reactivity of the primary amine groups was investigated. Methyl acrylate-glycine-cystamine (MA-Gly-CSA)-functionalized Au NCs with terminal acetyl groups were formed via the Michael addition reaction of terminal amine groups with methyl acrylate. This reaction resulted in the formation of ester-terminated Au NCs including atom-precise MA-Gly-CSA Au(SR) NCs. The functionalization of the ligand was confirmed by H NMR and UV-vis spectra, and TEM images of MA-Gly-CSA- and Gly-CSA-functionalized Au NCs showed that the size of the NCs remained unchanged after the reaction. With controllable NC size and facile functionalization of the Gly-CSA-functionalized Au NCs, these clusters have promising potential as scaffolds for biomedical applications.
本研究展示了一种改进的、简单的合成方法，可从保护的 Fmoc-甘氨酸-半胱氨酸（Fmoc-Gly-CSA）功能化的金纳米簇（NCs）中制备稳定的窄尺寸甘氨酸-半胱氨酸（Gly-CSA）功能化的 Au 纳米簇（NCs）。NC 的尺寸和尺寸分布可以直接作为还原剂浓度的函数进行控制，随着 NaBH 浓度的增加，NC 核直径更小。此外，当使用 0.30 M NaBH 时，在 690、440 和 390nm 处观察到三个紫外-可见吸收峰，这与 Fmoc-Gly-CSA 功能化的 AuL NCs 的形成一致。在 Gly-CSA 功能化的 Au NCs 脱保护后，研究了伯胺基团的反应性。通过末端胺基与甲基丙烯酰胺的迈克尔加成反应，形成末端带有乙酰基的甲基丙烯酰胺-甘氨酸-半胱氨酸（MA-Gly-CSA）功能化的 Au NCs。该反应导致形成酯端接的 Au NCs，包括原子精确的 MA-Gly-CSA Au（SR）NCs。通过 1 H NMR 和紫外-可见光谱证实了配体的功能化，并且 MA-Gly-CSA 和 Gly-CSA 功能化的 Au NCs 的 TEM 图像表明，NC 的尺寸在反应后保持不变。通过可控的 NC 尺寸和 Gly-CSA 功能化的 Au NCs 的简便功能化，这些簇作为生物医学应用的支架具有很大的潜力。
