| Abstract [eng] |
In this thesis, the photostability of hydrophilic thiol-capped quantum dots (QDs), which are intended for use in biological environments, was studied in model biosystems at different environmental conditions (in different ionic media and in medium with bovine serum albumin) and the phototoxic effects of these nanoparticles were investigated on unicellular freshwater algae. Several dose-dependent stages of quantum dots photomodification have been determined in aqueous media, and it has been also shown that these stages are reflected in various spectroscopic parameters of QDs. Moreover, the optical properties of QDs were markedly affected by ionic medium that stimulates the destructive effects of the irradiation, partial protection from which can be provided by serum albumin and unicellular algae. However, serum albumin and the light are independent factors that can influence the spectral properties of QDs of varying composition in the ionic medium, depending on the integral stability and the type of the surface ligand layer. Since the spectroscopic and microscopic methods are usable for both determining the photostability of the QDs and studying the impact of nanoparticles on autofluorescence of algae, they were applied to monitor the changes of autofluorescence of wild-type unicellular freshwater Scenedesmus sp. and Chlorella sp. algae cells induced by CdTe quantum dots capped with mercaptosuccinic acid, and the effect of nanoparticles on the photoadaptive response of algae cells has been observed. Also, for the first time, visualization of photoluminescence of quantum dots on membranes of some algae cells was done by applying techniques of fluorescence microscopy. |
