Bacterial cytotoxicity of the silver nanoparticle related to physicochemical metrics and agglomeration properties

Abstract

Silver particles are used in various consumer products due to their positive effects, which include sterilization and antibacterial properties. However, it has been reported that silver nanoparticles (AgNPs) have strongly acute toxic effects on various cells. Therefore, the cytotoxicity of AgNPs was investigated, using Escherichia coli as a model organism, from the standpoint of three key metrics (ionic ratio, size, and agglomeration) that are the most relevant physicochemical properties. The findings indicated that cytotoxicity is depressed by the agglomeration of AgNPs. The order of toxic sensitivity was as follows: total Ag concentration > ionic ratio > size, the order of which was inversely related to the extent of agglomeration.

Antibacterial activity of silver nanoparticles: A surface science insight

“…As the surface per unit of mass scales like 1/R (the number of particles scales like 1/R 3 and the surface like R 2 , with R the radius), it results that smaller NPs exhibit more active surface and are thus more prone to dissolution. For similar reasons, aggregated NPs expose less surface to the solvent than separated NPs, and thus possess a lower antibacterial impact [64]. While size of the NPs is a crucial parameter to determine their proper activity per unit of mass (or mole), it has been recently demonstrated by Liu et al [65] that the released Ag + scaled well if the sample were normalized by their exposed surface.…”

Catharanthus roseus: a natural source for the synthesis of silver nanoparticles

“…Nanoparticles present a higher surface area to volume ratio with decrease in the size of the particles. Specific surface area is relevant to catalytic activity and other related properties such as antimicrobial activity of AgNPs [3][4][5] . As the specific surface area of nanoparticles is increased, their biological effectiveness can also increase on the account of a rise in surface energy.…”

Fate of Engineered Nanoparticles in Wastewater Treatment Plant

“…Although the use of ENPs can be beneficial in many areas, unfortunately they are also dangerous for environmental matrix due to their possible toxicity [10]. Because of the risk of releasing ENPs into the natural environment this material threatens human health and ecosystems [11][12][13][14][15]. Released nanoparticles may either remain suspended in the atmosphere or be accumulated or be modified into other dangerous substances.…”

“…Throughout the wastewater treatment process ENPs can be removed from the wastewater streams through several mechanisms in the subsequent stages of the process [16]. These mechanisms can be assigned to one of the following groups: 1) sorption onto large debris and/or other large particles and further gravitional settling; 2) interaction with other pollutans for example: colloids, organic matters, metals; 3) agglomerate/conjugate for example: under the influence of addition of coagulants and flocculants; 4) aggregation 5) adhesion to sludge (microbal cell surfaces); 6) entrapment; 7) complexation; 8) degradation; 9) adsorption and interaction with extracellular polymeric substances [13]. Moreover, nanoparticles can be transformed during wastewater treatment via oxidation (e.g.…”