Preparation of Cadmium Telluride Quantum Dots and Its Effects on Cyclic Adenosine Monophosphate-cAMP Response Element-Binding Proteins-Brain-Derived Neurotrophic Factor Signaling Pathway in Mouse Hippocampus

Abstract

N-acetyl-L-cysteine-modified CdTe QDs (Cadmium Telluride Quantum Dots) were obtained by hydrothermal method, and DA (amino deoxyglucose), PEG (polyethylene glycol), and 9-p-D (9 polyamine acid) were obtained by ligand substitution, which were used for remodifying CdTe QDs. Successively, a novel CdTe QDs nanoma-terial, CdTe-NALC, was obtained. This composite nanometer material was characterized by ultraviolet, fluorescence spectrum, nuclear magnetic resonance hydrogen-spectrum, and other methods to study further its biocompatibility and toxic effect on the primary cultured mouse hippocampus neurons. PC12 cells were vitro-cultured and dissolved in the CdTe-NALC solution with different concentrations. After 24 h, the expression levels of proteins related to the cAMP (cyclic adenosine monophosphate)-CREB (cAMP response element-binding proteins)-BDNF (brain-derived neurotrophic factor) signaling pathway in the cells were detected by ELISA (enzyme-linked immunosorbent assay) kit. In the experiment, the DA/9-p-D/PEG-modified CdTe QDs composite nanometer material was successfully manufactured by ligand replacement. The nanoparticles had good dis-persibility with an average particle size of about 9.2 nm. DA/9-p-D/PEG modification improved the biocompatibil-ity of the QDs. CdTe composite nanomaterials could significantly reduce the cell activity of mouse hippocampal neurons and promote their apoptosis, with an evident dose-apoptosis relationship. With the increase of CDTE-NALC solution concentration, cAMP, pCREB (phosphorylated CREB), and BDNF protein content decreased (P < 0.05).