The disruption of bacterial membrane integrity through ROS generation induced by nanohybrids of silver and clay.
Nanohybrids, synthesized via silver nitrate reduction in the presence of silicate clay, exhibit a high potency against bacterial growth. The plate-like clay, due to its anionic surface charges and a large surface area, serves as the support for the formation of silver nanoparticles (AgNPs) approximately 30 nm in diameter. The nanohybrid consisting of Ag/silicate at a 7/93 weight ratio inhibited the growth of dermal pathogens including Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa and Streptococcus pyrogens, as well as the methicillin- and oxacillin-resistant S. aureus (MRSA and ORSA). Scanning electron microscope revealed that these nanohybrids were adherent on the surface of individual bacteria. The thin silicate plates provide a surface for immobilizing AgNPs in one highly concentrated area but prevent them from entering the cell membrane. Subsequent cytotoxicity studies indicated that surface contact with the reduced AgNPs on clay is sufficient to initiate cell death. This toxicity is related to a loss in membrane integrity due to reactive oxygen species (ROS) generation. The hybridization of AgNPs on clay surface is viable for generating a new class of nanohybrids exhibiting mild cytotoxicity but high efficacy for battling drug-resistant bacteria.
Su
Hong-Lin
HL
Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan. suhonglin@gmail.com
Chou
Chih-Cheng
CC
Hung
Da-Jen
DJ
Lin
Siou-Hong
SH
Pao
I-Chuan
IC
Lin
Jun-Hong
JH
Huang
Fang-Liang
FL
Dong
Rui-Xuan
RX
Lin
Jiang-Jen
JJ
D000538:Aluminum Silicates / Q000737:chemistry*; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D001672:Biocompatible Materials / Q000737:chemistry; D016923:Cell Death; D002462:Cell Membrane / Q000378:metabolism; D000077215:Clay; D004352:Drug Resistance, Microbial; D053768:Metal Nanoparticles / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning / Q000379:methods; D015233:Models, Statistical; D010316:Particle Size; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000378:metabolism*; D017382:Reactive Oxygen Species; D012834:Silver / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000378:metabolism*; D013297:Streptococcus pyogenes / Q000187:drug effects / Q000378:metabolism*
D000538:Aluminum Silicates; D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D017382:Reactive Oxygen Species; D012834:Silver; D000077215:Clay