Department of Thin Films and Nanostructures, Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i, Cukrovarnicka 10, CZ-162 53, Prague, Czech Republic.
Division of Biomolecular Physics, Institute of Physics of Charles University, Prague, Czech Republic.
Nanoscale Res Lett. 2016 Dec;11(1):367. doi: 10.1186/s11671-016-1593-4. Epub 2016 Aug 19.
We have prepared colloidal solutions of clusters composed from porous silicon nanoparticles in methanol, water and phosphate-buffered saline (PBS). Even if the size of the nanoclusters is between 60 and 500 nm, due to their highly porous "cauliflower"-like structure, the porous silicon nanoparticles are composed of interconnected nanocrystals having around 2.5 nm in size and showing strong visible luminescence in the orange-red spectral region (centred at 600-700 nm). Hydrophilic behaviour and good solubility of the nanoclusters in water and water-based solutions were obtained by adding hydrogen peroxide into the etching solution during preparation and 16 min long after-bath in hydrogen peroxide. By simple filtration of the solutions with syringe filters, we have extracted smaller nanoclusters with sizes of approx. 60-70 nm; however, these nanoclusters in water and PBS solution (pH neutral) are prone to agglomeration, as was confirmed by zeta potential measurements. When the samples were left at ambient conditions for several weeks, the typical nanocluster size increased to approx. 330-400 nm and then remained stable. However, both freshly filtered and aged samples (with agglomerated porous silicon nanoparticles) of porous silicon in water and PBS solutions can be further used for biological studies or as luminescent markers in living cells.
我们已经制备了胶体溶液，其中包含由多孔硅纳米粒子组成的纳米团簇，分散在甲醇、水和磷酸盐缓冲盐水（PBS）中。即使纳米团簇的尺寸在 60 到 500nm 之间，由于其高度多孔的“菜花”状结构，多孔硅纳米粒子由相互连接的纳米晶体组成，这些纳米晶体的尺寸约为 2.5nm，并在橙红色光谱区域（中心在 600-700nm）显示出强烈的可见光发光。通过在制备过程中向蚀刻溶液中添加过氧化氢，并在过氧化氢后处理 16 分钟，获得了纳米团簇在水中和水基溶液中的亲水性和良好的溶解性。通过用注射器过滤器简单过滤溶液，我们已经提取了尺寸约为 60-70nm 的较小纳米团簇；然而，这些在中性 pH 的水中和 PBS 溶液中的纳米团簇容易发生团聚，这一点通过zeta 电位测量得到了证实。当样品在环境条件下放置数周时，典型的纳米团簇尺寸增加到约 330-400nm，然后保持稳定。然而，无论是新鲜过滤的还是老化的（含有团聚的多孔硅纳米粒子）多孔硅在水中和 PBS 溶液中的样品，都可以进一步用于生物学研究或作为活细胞中的发光标记物。
