Evaluation Of Biological Toxicity Of Nanoparticles With Different Modifiers Using Engineering Escherichia Coli As A Model

Quantum dots and noble-metal nanoclusters are widely used in biological detection, biological sensing, imaging analysis, cancer detection, drug delivery and treatment because of their good optical properties. Investigating the biotoxicity of quantum dots and noble-metal nanoclusters will guide the researchers to develop new types of nano-materials with non-biotoxicity. And the popularization of these nano-materials in clinical application will be promoted. In this thesis, three kinds of CdTe QDs (TGA-CdTe QDs、GSH-CdTe QDs、Cys-CdTe QDs), three kinds of Au-NCs (BSA-Au NCs、 DHLA-Au NCs、GSH-Au NCs), two kinds of Ag-NPs (TGA-Ag NPs、BSA-Ag NCs) were synthesised, the biotoxicity of these nano-materials were detected by using E.coli as a model.1. A one-pot method has been developed for the synthesis of three kinds of CdTe QDs (TGA-CdTe QDs、GSH-CdTe QDs、Cys-CdTe QDs). The as-prepared CdTe QDs were characterized by fluorescence spectrophotometer, UV-Visible spectrophotometer and transmission electron microscopy. After incubation with E.coli named BL21/DE3, the SDS-PAGE was used to evaluate the expression of GST protein, and the expression of GST related to the biotoxicity of the three kinds of QDs. It was shown that TGA-CdTe QDs significantly decrease the expression of GST protein, and no apparent decrease of the expression of GST protein was found after incubation with GSH-CdTe QDs and Cys-CdTe QDs. The TEM showed that the shape E.coli changed from rod to stick. Further study indicate that the modifier may be the key role.2. A reduction method has been developed for the synthesis of three kinds of Au-NCs (BSA-Au NCs、DHLA-Au NCs、GSH-Au NCs) and two kinds of Ag-NPs (TGA-Ag NPs、 BSA-Ag NCs). The as-prepared Au-NCs and Ag-NPs were characterized by fluorescence spectrophotometer, UV-Visible spectrophotometer and transmission electron microscopy. The biotoxicity of these nano-materials were detected by using E.coli as a model. The result showed that both the Au-NCs and Ag-NPs exhibit nearly nontoxicity to E.coli revealing good biocoTGAtibility and potential appilication as nano fluorescent probes.