Studium koloidních suspenzí křemíkových nanokrystalů

• Main Author: Fučíková, Anna
• Other Authors: Valenta, Jan
• Format: Dissertation
• Language: Czech
• Published: 2007
• Online Access: http://www.nusl.cz/ntk/nusl-288859

This diploma thesis deals with optical and biophysical properties of colloidal suspensions of porous nanocrystalline silicon (por-Si) in different media, conditions necessary to create por-Si with different luminescence peaks and their optical characterization (emission and excitation spectra). The lifetime excited state = (28,6±0,9) us on emission wavelength 600 nm for orange emitting por-Si is measured by the time resolved fluorescence. The behaviour of por-Si and grinded silicon (crystals of size about 1um) in biological environment (L929 mouse fibroblast) is studied with optical transmission microscopy, time-lapse microphotography of cell culture evolution, fluorescent microscopy, and scanning electron microscopy (SEM). Transmission pictures prove an aggregation in presence of por-Si in media. This aggregates are going to internal environment of cells. At high concentration of grinded silicon we see meronecrosis. Por-Si has had also mildly negative effect on evolution of cell culture at very high concentrations, but cells are viable and cell division proceeds normally - next cell generation shows normal behaviour. Fluorescence microscopy used on orange emitting por-Si shows that por-Si is concentrated probably on cell membranes and its presence in internal cell environment is also proved. SEM proved...