Investigations into the antibacterial behavior of copper nanoparticles against Escherichia coli

Abstract

Zerovalent copper nanoparticles (Cu 0 ) of 12 nm size were synthesized using an inert gas condensation method in which bulk copper metal was evaporated into an inert environment of argon with subsequent cooling for nucleation and growth of nanoparticles. Crystalline structure, morphology and estimation of size of nanoparticles were carried out by X-ray diffraction and transmission electron microscopy. The antibacterial activity of these nanoparticles against the Gram-negative bacterium Escherichia coli was assessed in liquid as well as solid growth media. It was observed from scanning electron microscopic analysis that the interaction of copper nanoparticles with E. coli resulted in the formation of cavities/pits in the bacterial cell wall. The antibacterial property of copper nanoparticles was attributed mainly to adhesion with bacteria because of their opposite electrical charges, resulting in a reduction reaction at the bacterial cell wall. Nanoparticles with a larger surface-to-volume ratio provide more efficient means for antibacterial activity.

In vitro effects of copper nanoparticles on plant pathogens, beneficial microbes and crop plants

“…It has been described that CuNPs of size 12 nm interact with the cell wall of Gram-negative bacterium E. coli and form cavities in the wall (Raffi et al, 2010). Opposite electrical charge of CuNPs make them adhere to the bacterial cell wall resulting in certain reduction reaction (Raffi et al, 2010).…”

“…Reports of antimicrobial effects of CuNPs are mainly focussed on microbes of human importance (Yoon et al, 2007;Raffi et al, 2010) or food industry (Cioffi et al, 2005;Jia et al, 2012), whereas those on agriculturally important plant pathogens and/or beneficial microbes are scarce. There has been little systematic study on the various biological components of the agro-ecosystem involving plants, plant pathogens and beneficial microbes together and addressing both the opportunities and threats of any nanoparticles.…”

Synthesis, Characterization and Antimicrobial Activity of Zinc Oxide Nanoparticles against Drug-Resistant Escherichia coli Isolated from Potable Water

“…The exhaustive use of antimicrobial agents has generated the selective pressure to encourage the gradually increasing rates for antimicrobial resistance (Levy, 2004). Hence there is no single antimicrobial agent available for human and animal use that has not demonstrated resistance against microorganisms (Raffi, 2010). There has been much recent interest in using silver, zinc and copper nanoparticles in new technologies with respect to their improved properties such as high and reactive surface area of nano size materials (Lee, 2013).…”

Antibacterial activity of thin films TiO2 doped with Ag and Cu on Gracilicutes and Firmicutes bacteria

“…The osteoblastic adhesion, spreading, early proliferation and late differentiation on Cu-TiO coatings were significantly enhanced due to the inhibitory effect of Cu and existence of a suitable porous nano-structured surface Han et al (2008), Zhao et al (2009). Excellent antibacterial properties of Cu-doped TiO coatings were reported by Raffi et al (2010). They accept that the reason for the antibacterial property of Cu NPs is their adhesion on to the bacterial surface due to their opposite charge with respect to bacteria.…”