Zinc Oxide Nanoparticles Dispersed in Ionic Liquids Show High Antimicrobial Efficacy to Skin-Specific Bacteria

Abstract

Zinc oxide (ZnO) nanoparticles have been shown in the literature to have antibacterial properties and have been widely used in antibacterial formulations. However, one of the problems with ZnO nanoparticles is their tendency to aggregate, thereby causing damage to normal cells and lowering their antibacterial efficacy during application. In this work, we have attempted to avoid this by using a combination of ZnO nanoparticles and ionic liquids, a class of low melting salts containing organic cations and organic/inorganic anions that show antibacterial property as well, and tested the antibacterial activity of this dispersion. ZnO nanoparticles of 60 nm were dispersed in two different ionic liquids-choline acetate (IL1) and 1-butyl-3-methylimidazolium chloride (IL2)-to achieve high dispersibility, whereas ZnO dispersed in phosphate-buffered saline was taken as a control. These dispersions were tested on four strains- Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, and Staphylococcus epidermidis. Maximum efficiency was obtained for ZnO nanoparticles dispersed in imidazolium-based ionic liquids against skin-specific S. epidermidis. Skin infections induced by S. epidermidis are prevalent in hospital-acquired diseases. In most cases, traditional antibiotic-based therapies fail to combat such infections. Our strategy of developing a dispersion of ZnO nanoparticles in ionic liquids shows superior antibacterial efficacy in comparison to that shown individually by ZnO nanoparticles or ionic liquids. We have also established that the mechanism of killing this skin-specific bacterium is possibly through the production of reactive oxygen species leading to bacterial cell lysis. Further, we showed that this formulation is biocompatible and nontoxic to normal keratinocyte cells even under coculture conditions.

<p>Photocatalytic antibacterial application of zinc oxide nanoparticles and self-assembled networks under dual UV irradiation for enhanced disinfection</p>

“…1,2 They have been highlighted as natural alternatives to TiO 2 nanoparticles in various research fields such as photocatalysis and energy storage. 2,3,23 Among the bioapplications of ZnO nanoparticles, [4][5][6][7][8][9][10][11][12][13] they have been reported to be photocatalytic antibiotics against bacteria and phages. 5,6,[8][9][10][11][12][13] For general antimicrobial therapy, ZnO nanoparticles also demonstrated therapeutic potential in human pathogens (minimum inhibitory concentration values: 30-80 µg/mL), suggesting the possibility of their use as combination agents with other antibiotics such as cefotaxime and ceftriaxon.…”

“…2,3,23 Among the bioapplications of ZnO nanoparticles, [4][5][6][7][8][9][10][11][12][13] they have been reported to be photocatalytic antibiotics against bacteria and phages. 5,6,[8][9][10][11][12][13] For general antimicrobial therapy, ZnO nanoparticles also demonstrated therapeutic potential in human pathogens (minimum inhibitory concentration values: 30-80 µg/mL), suggesting the possibility of their use as combination agents with other antibiotics such as cefotaxime and ceftriaxon. 5,[8][9][10][11][12][13] In the present study, the enhanced antibacterial activities of dual UV-irradiated ZnO nanoparticles and multilevel porous networks on Si wafers against E. coli have been reported.…”

“…5,6,[8][9][10][11][12][13] For general antimicrobial therapy, ZnO nanoparticles also demonstrated therapeutic potential in human pathogens (minimum inhibitory concentration values: 30-80 µg/mL), suggesting the possibility of their use as combination agents with other antibiotics such as cefotaxime and ceftriaxon. 5,[8][9][10][11][12][13] In the present study, the enhanced antibacterial activities of dual UV-irradiated ZnO nanoparticles and multilevel porous networks on Si wafers against E. coli have been reported. The physicochemical properties of these nanoparticles and networks were determined using XPS, FE-SEM, FE-TEM, and AFM.…”

“…ZnO nanoparticles are attractive potential broad-spectrum nanoantibiotics. ZnO nanoparticles and their nanoparticles adopted by other metal/metal oxides and other polymers have antimicrobial activity against Escherichia coli, 6,[8][9][10][11] Staphylococcus aureus, [8][9][10] Klebsiella pneumoniae, 11 M13 bacteriophages, 6 and skin-specific pathogens 12 with/without UV irradiation. They also have antimicrobial activity against methicillin-resistant S. aureus based on modification of reactive oxygen species (ROS)-mediated pyridine synthesis and multiple metabolic pathways.…”

ZnO NPs delay the recovery of psoriasis-like skin lesions through promoting inflammation and keratinocyte apoptosis via nuclear translocation of phosphorylated NF-κB p65 and cysteine deficiency

“…For many years, zinc oxide (ZnO) has been widely used in food, pharmaceuticals, cosmetics and other chemicals used on a daily basis, and formulations of these products containing ZnO nanoparticles (ZnO NPs) are more popular than conventional formulations [1][2][3][4]. The content of ZnO NPs in certain topical drugs and cosmetics that frequently contact the skin is high.…”