Adhesion of quantum dots-induced membrane damage of Escherichia coli

• Published in: Journal of colloid and interface science Vol. 389; no. 1; pp. 61 - 70
• Main Authors: Lai, Lu, Lin, Chen, Xiao, Chang-Qing, Xu, Zi-Qiang, Han, Xiao-Le, Fu, Li, Li, Dong-Wei, Mei, Ping, Jiang, Feng-Lei, Guo, Qing-Lian, Liu, Yi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.01.2013; Elsevier
• Subjects: absorbance; acetylcysteine; Acetylcysteine - chemistry; Acetylcysteine - toxicity; Adhesion; adsorption; atomic absorption spectrometry; bacterial adhesion; cadmium; Cadmium Compounds - chemistry; Cadmium Compounds - toxicity; calorimetry; CdTe QDs; cell suspension culture; Chemistry; Colloidal state and disperse state; energy; Escherichia coli; Escherichia coli - drug effects; Exact sciences and technology; General and physical chemistry; glutathione; Glutathione - chemistry; Glutathione - toxicity; hydrodynamics; hydrophobicity; Ligands; Membrane fluidity; Membrane permeability; Membranes; Microcalorimetric methods; Particle Size; permeability; Quantum Dots; Sulfhydryl Compounds - chemistry; Sulfhydryl Compounds - toxicity; Tellurium - chemistry; Tellurium - toxicity; Toxicity; Toxicity Tests; transmission electron microscopy; NAC; QDs; Membrane fluidity; Microcalorimetric methods; Toxicity; CdTe QDs; Membrane permeability; GSH; Adhesion; MPA; Quantum dot; Fluidity; Transition element compounds; Membrane; Permeability
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2012.09.002

[Display omitted] ► The toxicity order of QDs is MPA>GSH>NAC. ► The toxicity may be related to the adsorption of QDs to the surface of Escherichia coli. ► The adsorption induces a decrease in membrane fluidity and an increase in permeability. ► GSH-CdTe QDs have a greater effect on the cell membrane than others. The toxicity of CdTe QDs modified with three different ligands, namely mercaptopropionic acid (MPA), N-acetyl-l-cysteine (NAC), and glutathione (GSH), were investigated via microcalorimetric, spectroscopic, and microscopic methods. The three ligand-modified QDs have nearly identical hydrodynamic size. The results of the calorimetric experiments and optical density measurements indicate that the QDs inhibited the growth of Gram-negative Escherichia coli. The toxicity order of the three QDs is MPA-CdTe QDs>GSH-CdTe QDs>NAC-CdTe QDs. The inhibitory effects of the QDs, cadmium chloride (CdCl2), MPA, and the CdCl2 and MPA mixture on E. coli growth indicate that the toxicity mechanism of QDs may be related to their bacterial adhesion. When dispersed in the cell suspensions, QDs tend to have their high surface energy reduced through adsorption to the bacterial surface, as confirmed by transmission electron microscopy and inductively coupled plasma atomic emission spectroscopy results. Furthermore, the effect of QDs on the membrane fluidity and permeability was investigated. GSH-CdTe QDs have a greater effect on the membrane function of E. coli than those of MPA-CdTe and NAC-CdTe QDs. This result may be attributed to the stronger lipophilicity of GSH compared with those of MPA and NAC.