Role of sulfide and ligand strength in controlling nanosilver toxicity

Micromorphological cellular responses of MC3T3-E1 and RAW264.7 after exposure to water-dispersible silver nanoparticles stabilized by metal-carbon σ-bonds

“…It has also been reported that Ag-NPs dissolve and generate silver ions, resulting in disruption of ATP production, DNA replication, and ROS generation under certain cellular condition 19,21) . Surface capping of nanoparticles prevented silver ion release, leading to decreased cytotoxicity for cells and organs 22,23) . Therefore, this modification can enhance stability and improve the biocompatibility of these materials 19) .…”

Potential scenarios for nanomaterial release and subsequent alteration in the environment

“…Geranio et al [13] observed that little dissolution of Ag occurred under the high-pH conditions typical of textile washing and that most of the nano-Ag was released in a particle size fraction >450 nm as a result of mechanical stress from the washing action. Once released into the aquatic environment, the transformation and toxicity of nano-Ag or dissolved species appear to be tightly linked to physicochemical parameters, including the concentrations and types of dissolved organic matter, pH and ionic strength, redox environment, and presence of inorganic ligands [2,77]. Thus, as illustrated in Figure 4, the primary fate processes that affect the distribution of nano-Ag from textiles in the environment are abrasion (process 8), oxidation (process 2), dissolution and precipitation (process 4), adsorption and desorption (process 5), and microbial transformation (process 7), processes that can take place during the release from washed fabrics, in the WWTP during treatment, and in the receiving environment (agricultural soils, surface waters).…”

Analysis of engineered nanomaterials in complex matrices (environment and biota): General considerations and conceptual case studies

“…Engineered AgNPs present in a wastewater stream are likely to encounter common ligands such as sulfate, sulfide, chloride, and phosphate, as well as carboxylic acids, polyalcohols, and amines found in humic substances [86]. Many of these ligands that are often associated with particulate matter are known to either complex directly with engineered AgNPs or with Ag þ , which may be released during oxidation.…”

“…Silver sulfide has been identified recently in the form of nanoparticles (5-20 nm ellipsoids) in final stage sewage sludge materials in a full-sized municipal wastewater treatment plant [88]. Kim et al suggested, based on the results of Choi et al [86], that the source of the silver sulfide nanoparticles may have been engineered AgNPs. The reported change in the chemical composition of the ENPs in the wastewater treatment system may have significant biological consequences.…”

“…In addition to forming nanoscale Ag x S y complexes and precipitates, the presence of sulfide also protects nitrifying bacteria from the toxic effect of both Ag þ and engineered AgNPs [89]. Other inorganic ligands present in wastewater such as sulfate, chloride, and phosphate were significantly less effective in reducing engineered AgNP toxicity [86].…”