silver brands

Molecular formula: Ag

The majority of released silver ions precipitate with chloride or phosphate anions or bind to albumins, macroglobulins, or tissue debris. While bound silver ions do not exert antibacterial actions, they may potentially play a role in silver toxicity in case of chronic exposure. Silver ions mediate antibacterial effects via disrupting the bacterial, fungal, and protozoal cell membranes; they bind to disulphide in membrane proteins, readily allowing penetration through the membranes and intracellular absorption via pinocytosis. They may also bind to negatively-charged peptidoglycans in the cell wall via electrostatic interactions, leading to disruption of membrane transport function and loss of structural integrity. Silver ions also bind to and oxidize sulphydryl groups (SH) in bacterial cytoplasmic enzymes to aberrate their function in metabolic processes. Silver nanoparticles may cause an increase in reactive oxygen species (ROS) inside the microbial cells leading to metal-induced oxidative stress and cell damage. They also modulate cellular signal system via inhibition of phosphorylation of essential bacterial proteins to eventually cause cell death. It is also reported that silver ions also attach to guanine in bacterial DNA, which inhibits DNA replication. While it is not fully understood, the mode of action of silver compounds in preventing and arresting dental caries is thought to involve inhibition of the demineralization process in addition to cytoplasmic and membrane function perturbation mentioned above. Silver compounds may directly interact with hydroxyapatite, a major tooth component. Light catalyzes the reduction of silver salts deposited in skin to metallic silver & it /is/ subsequently oxidized to silver sulfide; it is the deposition of the latter compound which accounts for the gray discoloration pathognomonic of argyria. /Silver and compounds/ Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. In this study, spherical nano-Ag (average diameter = 9.3 nm) particles were synthesized using a borohydride reduction method and the mode of their antibacterial action against E. coli was investigated by proteomic approaches (2-DE and MS identification), conducted in parallel to analyses involving solutions of Ag(+) ions. The proteomic data revealed that a short exposure of E. coli cells to antibacterial concentrations of nano-Ag resulted in an accumulation of envelope protein precursors, indicative of the dissipation of proton motive force. Consistent with these proteomic findings, nano-Ag were shown to destabilize the outer membrane, collapse the plasma membrane potential and deplete the levels of intracellular ATP. The mode of action of nano-Ag was also found to be similar to that of Ag(+) ions ... however, the effective concentrations of nano-Ag and Ag(+) ions were at nanomolar and micromolar levels, respectively. Nano-Ag appear to be an efficient physicochemical system conferring antimicrobial silver activities.

Source: PubChem (NCBI) · compound 23954