FLUORESCENCE PROPERTIES OF QUANTUM DOTS

The aim of this study was the synthesis of CdTe quantum dots (QDs) and study of their fluorescence properties and their potential for the use in the bioimaging. QDs are small semiconductor nanoparticles (1 - 20 nm), which can be used in the imaging instead of the organic labels. The CdTe QDs were synthesised by microwave synthesis in an aqueous solution. As the source of telluride, Na2TeO3 was used, and as reduction agent, sodium borohydride was applied. Quantum dots were stabilized by mercaptosuccinic acid (MSA). According to reaction conditions (temperature: 50 130 degrees C), size of prepared quantum dots can be tuned. Synthesised QDs had got very good fluorescence properties and were used for the cell labelling. The QDs penetrated into the cells and stained plant cells, as well as human foreskin fibroblasts. But the changes in the cells shapes were observed, the reason could be the toxic effect of QDs, which should be more investigated. For the usage of QDs in medicine, it is necessary to know their behaviour in the tissue. We investigated the behaviour of QDs in the chicken breast muscle tissue. After the direct injection of QDs into the muscle tissue, sufficient spreading of QDs in the tissue was observed and a significant linear increase of the fluorescence intensity of QDs with applied volume was determined. To detect the limiting depth for the signal detection, the tubes filled with different QDs was inserted into the different depths of the tissue. The intensity of the fluorescence of QDs depended on the size of QDs, therefore red QDs was possible to detect the most deeply (10 mm). Using the different emission filters, it is possible to distinguish between the different QDs. It enables the use QDs in the simultaneously labelling of different structures in the cells or the organisms.