Simultaneous control of size and surface functionality of silica particle via growing method

Although silane treatment has been studied as a simple and powerful tool to modify the surface of silica particle, there are still several difficulties in terms of controlling surface functionality and size of nanoparticles. Here we develop a growing method to overcome above drawback. The method was processed by continuously injecting precursor using syringe pump. According to the continuous injection, the concentration of precursors in media are properly controlled, and then the continuous injection of precursor promotes the growth of silica particles. When the functional silanes (silane coupling agents) are used, the method can control the amount of surficial functional groups on the silica particle, and can adjust diameter of the particle simultaneously. Furthermore, well-controlled functional silica particles made by growing method are used for catalytic reaction, Knoevenagel reaction, as a solid state catalyst.     

Effect of exposure temperature on the cell membrane disruption induced by amorphous silica nanoparticles in erythrocytes,lymphocytes, and malignant melanocytes

It is of great significance to examine carefully the potentially harmful effects of silica-based nanoparticles (NPs) on human body. In the present study, we have investigated the impact of exposure temperatures (4 °C, 15 °C, 26 °C, and 37 °C) on the cell membrane disruption induced by amorphous silica NPs of different primary diameters (28, 55, 88, 156, and 461 nm) in three different types of cells (erythrocytes, Jurkat, and B16F10), where the serum-free culture media were employed for exposure of the cells to the silica NPs. The size- and dose-dependent membranolytic activity of the silica NPs in each cell type at every temperature appeared to be given by a master curve as a function of the NP surface area per suspension volume, regardless of the NP diameter. This silica-induced membranolysis was significantly enhanced by the higher-temperature exposure of each cell type to the silica NPs. Such effects of exposure temperature on the silica-induced membranolysis in non-adherent cells of RBC and Jurkat were quite similar to each other, regardless of their difference in the presence/absence of nucleus and endocytic ability, whereas that for adherent cells of B16F10 was more remarkable. The filterability of erythrocytes also was measured at different temperatures, whereby the effect of temperature on the deformability of cell membranes was estimated. A possible mechanism underlying the effect of exposure temperature on the silica-induced membranolysis was proposed.