In vitroAntimicrobial Activity Evaluation of Metal Oxide Nanoparticles

Abstract

In recent years, infectious diseases, specifically those that are caused by pathogens, have seen a dramatic proliferation due to resistance to multiple antibiotics, opening the colony by opportunistic pathogens. Nanotechnology and tissue engineering have been applied in the development of new antimicrobial therapies, capable of fighting opportunistic infections. In the medical field, research on antimicrobial properties of metal oxide nanoparticles have emerged to find new antimicrobial agents as an alternative against resistant bacteria. The metal oxides, particularly those formed by transition metals are compounds with electronic properties, and most magnetic phenomena involve this type of oxides. Nanoparticlesbased metal oxide properties such as shape, size, roughness, zeta potential and their large surface area, make oxides ideal candidates to interact with bacteria and able to have an antimicrobial effectiveness. The aim of this chapter is to offer an updated panorama about the relationships between the use of metal oxide nanoparticles in the medical field, with an emphasis on their role as antimicrobial agents and the properties that influence their antimicrobial response. In addition, the mechanism of nano-antimicrobial action is described and the importance of using in vitro test methods, adopted by leading international regulatory agencies, that can be used to determine the antimicrobial activity of the metal oxide nanoparticles.

Silver ion bioreduction in nanoparticles using Artemisia annua L. extract: characterization and application as antibacterial agents

“…Effects on membrane permeability and membrane-associated key enzymes including the proton F O F 1 -ATPase can be main mechanisms of Ag NPs (Gabrielyan and Trchounian 2019). Formation of complexes of nucleic acid with heavy metals is due to impaired DNA stabilizing and bacterial viability (Sondi and Salopek-Sondi 2004;Vega-Jimenez et al 2019). Ag does not affect the cells' DNA directly; however, it increases the number of intracellular free radicals that reduce the concentration of intracellular active oxygen compounds (Sondi and Salopek-Sondi 2004;Bhabra et al 2009;Wu et al 2013).…”

“…Ag does not affect the cells' DNA directly; however, it increases the number of intracellular free radicals that reduce the concentration of intracellular active oxygen compounds (Sondi and Salopek-Sondi 2004;Bhabra et al 2009;Wu et al 2013). It was also assumed that interaction of Ag ions with ribosomes led to inhibition of enzymes and protein expression necessary for ATP production (Gurunathan et al 2014;Bhabra et al 2009;Vega-Jimenez et al 2019). The mechanism of antibacterial effects of Ag NPs are still not clearly understood, but some studies have shown that Ag NPs may attach to the negatively charged bacterial cell wall and cleave it, which leads to protein denaturation and cell death (Sondi and Salopek-Sondi 2004;Wu et al 2013;Chandran et al 2014).…”

“…Thus, the bactericidal effect depends on the concentrations, and it is specific for each bacterial strain. The antibacterial activity of synthesized Ag NPs may be connected to the nano-sizes and spherical shape of the Ag NPs, NPs' surface charge and also to the large surface area of Ag NPs, which makes them highly reactive and provides better interaction with bacterial cells (Sondi and Salopek-Sondi 2004;Vega-Jimenez et al 2019). The positively charged Ag NPs show bactericidal and bacteriostatic activity (Roy et al 2019).…”

“…The size of NPs is one of the most important properties for antibacterial activity. Particular small NPs have high antibacterial activity (Waclawek et al 2018;Vega-Jimenez et al 2019) due to their large surface area and high intracellular penetration (Roy et al 2019). Preferably, the size of NPs must be lower than 50 nm to acquire effective antibacterial activity, however very small NPs (< 10 nm) are toxic due to their higher intracellular bioavailability.…”

Green Synthesis of Zinc Oxide Nanoparticles from Pomegranate (Punica granatum) Extracts and Characterization of Their Antibacterial Activity

“…These processes ultimately result in the disruption of the bacterial cell membrane structure, leading to cell death [ 2 , 3 ]. Recent studies have demonstrated that bacterial pathogens are exhibiting resistance against a variety of antibiotics [ 4 ], thereby limiting the effectiveness of these agents [ 5 ]. Contrary to the modes of action of antibiotics, bacterial strains are able to express antimicrobial resistance by: (1) altering the target of antibiotics by expressing genes that code for an alternate version of the antibiotic target [ 6 , 7 , 8 ]; (2) developing enzymes that can degrade or modify the drug [ 1 , 8 ]; (3) ensuring reduced uptake of antimicrobial drugs or acting as efflux pumps that push out the drugs [ 3 , 6 ]; and (4) formation of biofilm layers around the bacterial cell, thus limiting or reducing its exposure to antibiotics [ 8 , 9 ].…”