Phytotoxic effects of CdTe quantum dots on root meristems of Allium cepa L.

The effect of solutions of cadmium telluride quantum dots (CdTe QD) as powerful cytotoxic effectors was investigated using a standard Allium cepa L. test system. The diameters of synthesized CdTe QD derived from the optical data varied within 3 – 4 nm. Toxicity of experimental solutions of CdTe QD at the organism level were evaluated by measuring biomass growth of onion roots and cytotoxic influence was estimated based on proliferative activity of root meristem cells. All of CdTe QD experimental solutions in concentration 10 µM significantly inhibited the growth of Allium cepa L. roots, proliferative activity, and total dehydrogenase activity. Relation between the QDs size and their phytotoxicity was not found. However, the highest inhibiting impact was for QDs solution with a nanocrystals size of 3.5 nm. Their ability to penetrate into cells and interact with their intracellular components may cause inhibiting mitosis without fixed clastogenic and aneugenic effects. Solutions of CdTe QD at a given concentration can be considered as potent cytostatic agents for plant cells with antimitotic properties.

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

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).

Gene Expression and Transcriptome Profiling of Changes in a Cancer Cell Line Post-Exposure to Cadmium Telluride Quantum Dots: Possible Implications in Oncogenesis

Cadmium telluride quantum dots (CdTe-QDs) are acquiring great interest in terms of their applications in biomedical sciences. Despite earlier sporadic studies on possible oncogenic roles and anticancer properties of CdTe-QDs, there is limited information regarding the oncogenic potential of CdTe-QDs in cancer progression. Here, we investigated the oncogenic effects of CdTe-QDs on the gene expression profiles of Chang cancer cells. Chang cancer cells were treated with 2 different doses of CdTe-QDs (10 and 25 μg/ml) at different time intervals (6, 12, and 24 h). Functional annotations helped identify the gene expression profile in terms of its biological process, canonical pathways, and gene interaction networks activated. It was found that the gene expression profiles varied in a time and dose-dependent manner. Validation of transcriptional changes of several genes through quantitative PCR showed that several genes upregulated by CdTe-QD exposure were somewhat linked with oncogenesis. CdTe-QD-triggered functional pathways that appear to associate with gene expression, cell proliferation, migration, adhesion, cell-cycle progression, signal transduction, and metabolism. Overall, CdTe-QD exposure led to changes in the gene expression profiles of the Chang cancer cells, highlighting that this nanoparticle can further drive oncogenesis and cancer progression, a finding that indicates the merit of immediate in vivo investigation.