Bacterial phototoxicity of biomimetic CdTe-GSH quantum dots
Open Access
- 1 July 2021
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Applied Microbiology
- Vol. 131 (1), 155-168
- https://doi.org/10.1111/jam.14957
Abstract
Aim: Fluorescent semiconductor nanoparticles or quantum dots (QDs) have excellent properties as photosensitizers in photodynamic therapy. This is mainly a consequence of their nanometric size and the generation of light-activated redox species. In previous works, we have reported the low-cost biomimetic synthesis of glutathione (GSH) capped QDs (CdTe-GSH QDs) with high biocompatibility. However, no studies have been performed to determine their phototoxic effect. The aim of this work was to characterize the light-induced toxicity of green (QDs(500)) and red (QDs(600)) QDs in Escherichia coli, and to study the molecular mechanism involved. Methods and Results: Photodegradation and reduction power of biomimetic QDs was determined to analyse their potential for radical generation. Escherichia coli cells were exposed to photoactivated QDs and viability was evaluated at different times. High toxicity was determined in E. coli cells exposed to photoactivated QDs, particularly QDs(500). The molecular mechanism involved in QDs phototoxicity was studied by determining Cd2+-release and intracellular reactive oxygen species (ROS). Cells exposed to photoactivated QDs(500) presented high levels of ROS. Cells exposed to photoactivated QDs(500) presented high levels of ROS. Finally, to understand this phenomenon and the importance of oxidative and cadmium-stress in QDs-mediated phototoxicity, experiments were performed in E. coli mutants in ROS and Cd2+ response genes. As expected, E. coli mutants in ROS response genes were more sensitive than the wt strain to photoactivated QDs, with a higher effect in green-QDs(500). No increase in phototoxicity was observed in cadmium-related mutants. Conclusion: Obtained results indicate that light exposure increases the toxicity of biomimetic QDs on E. coli cells. The mechanism of bacterial phototoxicity of biomimetic CdTe-GSH QDs is mostly associated with ROS generation. Significance and Impact of the Study: The results presented establish biomimetic CdTe-GSH QDs as a promising cost-effective alternative against microbial infections, particularly QDs(500).This publication has 73 references indexed in Scilit:
- DNA, Cell Wall and General Oxidative Damage Underlie the Tellurite/Cefotaxime Synergistic Effect in Escherichia coliPLOS ONE, 2013
- Enhanced Glutathione Content Allows the In Vivo Synthesis of Fluorescent CdTe Nanoparticles by Escherichia coliPLOS ONE, 2012
- Biomimetic, Mild Chemical Synthesis of CdTe-GSH Quantum Dots with Improved BiocompatibilityPLOS ONE, 2012
- In vivomolecular imaging using nanomaterials: Generalin vivocharacteristics of nano-sized reagents and applications for cancer diagnosis (Review)Molecular Membrane Biology, 2010
- Imaging and Photodynamic Therapy: Mechanisms, Monitoring, and OptimizationChemical Reviews, 2010
- Cadmium-containing nanoparticles: Perspectives on pharmacology and toxicology of quantum dotsToxicology and Applied Pharmacology, 2009
- Bioconjugated quantum dots for in vivo molecular and cellular imagingAdvanced Drug Delivery Reviews, 2008
- Glutathione and Transition-Metal Homeostasis inEscherichia coliJournal of Bacteriology, 2008
- Bacterial Toxicity of Potassium Tellurite: Unveiling an Ancient EnigmaPLOS ONE, 2007
- Construction of Escherichia coli K‐12 in‐frame, single‐gene knockout mutants: the Keio collectionMolecular Systems Biology, 2006