Research On The Preparation, Photo-catalysis And Bioactivities Of Aqueous CdTe Quantum Dots

Semiconductor quantum dots (QDs) are luminescent nanoparticles that are under intensive development for use as a new calss of fluorescence probes for bio-medical applications. In this article, we prepared the CdTe QDs in aqueous solution using thioglycolic acid as stabilizing agent. After appropriate illumination by the sunshine and storage, we got the mature QDs whose photoluminescence characteristic (PL) and stability were improved obviously.Ethidium Bromide (EB), a intercalating fluorescence probe for the recognition of nucleic acids, has been widely applied in bio-medical research, is also known as a famous carcinogen. We tried to investigate the degradation of EB using nano CdTe quantum dots synthesized in aqueous phase as a photo-catalyzer. Factors that concern with a photocatalysis reaction including pH and irradiation time were also investigated. The results showed that the degradation efficiency was satisfied when the photo-catalyzed reaction was carried out under optimal conditions. This method also has employed in the process of EB presented in DNA electrophoresis gel with satisfying results.There is still lack of sufficient analysis of the nanotoxicity of QDs. This lead to the work in the fourth chapter that we performed ames test and MTT assay to determine the bioactivities of CdTe QDs. The results showed less mutagenicity of CdTe QDs compared with that of CdCl2, whether with S9 metabolic or not. It also showed that the QDs were biocompatible with Hela cells in appropriate concentration in vitro. Cell viability only decreased with a high concentration of the nanoparticles. It may be suggested that CdTe QDs modified with light were safe for biological and medicinal applications.