Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1.
ACS Appl Mater Interfaces. 2012 Aug;4(8):3980-6. doi: 10.1021/am300809q. Epub 2012 Jul 24.
Several strategies have been described for the preparation of silica-encapsulated gold nanoparticles (SiO(2)-AuNP), which typically suffer from an initial interface between gold and silica that is difficult to control, and layer thicknesses that are very sensitive to minor changes in silane concentration and incubation time. The silica shell thicknesses are normally equal to or larger than the gold particles themselves, which is disadvantageous when the particles are to be used for biodiagnostic applications. We present a facile and reproducible method to produce very thin silica shells (3-5 nm) on gold nanoparticles: the process is highly tolerant to changes in reaction conditions. The method utilized polyvinylpyrrolidone (PVP) of specific molecular weights to form the interface between gold and silica. The method further requires a nontraditional silica precursor, diglycerylsilane, which efficiently undergoes sol-gel processing at neutrality. Under these conditions, higher molecular weight PVP leads to thicker silica shells: PVP acts as the locus for silica growth into an interpenetrating organic-inorganic hybrid structure.
已经描述了几种制备二氧化硅包裹金纳米粒子（SiO(2)-AuNP）的策略，这些策略通常存在金和二氧化硅之间难以控制的初始界面，以及层厚度对硅烷浓度和孵育时间的微小变化非常敏感的问题。二氧化硅壳层的厚度通常与金颗粒本身相等或更大，这在将颗粒用于生物诊断应用时是不利的。我们提出了一种简便且可重复的方法来制备金纳米颗粒上非常薄的二氧化硅壳（3-5nm）：该过程对反应条件的变化具有高度的耐受性。该方法利用特定分子量的聚乙烯吡咯烷酮（PVP）在金和二氧化硅之间形成界面。该方法还需要一种非传统的硅烷前体，二缩水甘油基硅烷，它在中性条件下能有效地进行溶胶-凝胶处理。在这些条件下，高分子量的 PVP 会导致更厚的二氧化硅壳：PVP 充当了硅在互穿有机-无机杂化结构中生长的位置。
