Are silver ions toxic to humans
Pro Research Analysisby 
Searched over 200M research papers
Toxicity of Silver Ions to Humans
Introduction to Silver Ion Toxicity
Silver ions (Ag+) are widely used for their antimicrobial properties in various medical and consumer products. However, their potential toxicity to human cells has raised concerns. This article synthesizes research findings on the toxic effects of silver ions on human health.
Oxidative Stress and Cellular Damage
Oxidative Stress Induction
Silver ions induce oxidative stress in human cells, leading to the production of reactive oxygen species (ROS) such as superoxide anion radicals. This oxidative stress results in a significant decrease in intracellular reduced glutathione, making cells more susceptible to oxidative damage and cell death .
Impact on Antioxidant Genes
Exposure to silver ions down-regulates the expression of key antioxidant genes, including the transcription factor Nrf2 and its target gene glutamate-cysteine ligase catalytic subunit. This down-regulation further exacerbates oxidative stress in human skin fibroblasts.
Toxicity Across Different Cell Types
Comparative Toxicity
Studies have shown that the toxic effects of silver ions occur within a similar concentration range for both bacterial and human cells. For instance, silver ions exhibit toxicity at concentrations of 0.5 to 5 ppm for human mesenchymal stem cells (hMSCs) and peripheral blood mononuclear cells (PBMCs).
Liver Cell Toxicity
In human hepatoma cells, silver ions reduce cell viability in a dose-dependent manner, causing membrane damage and reduced cell function. This is evidenced by increased lactate dehydrogenase (LDH) leakage and inhibition of albumin synthesis.
Systemic Absorption and Metabolism
Absorption and Distribution
Orally administered silver is absorbed at a rate of up to 18% in humans and is distributed to various organs, with the highest levels found in the intestine and stomach. Silver is excreted primarily through bile and urine.
Argyria and Argyrosis
Chronic exposure to silver can lead to argyria, a condition characterized by blue-grey discoloration of the skin, and argyrosis, which affects the eyes. These conditions are not life-threatening but are cosmetically undesirable .
Safety in Medical Applications
Low Toxicity in Clinical Use
Despite the potential for toxicity, silver exhibits low toxicity in the human body when used in medical applications such as wound care and surgical devices. The risk of systemic toxicity from clinical exposure is minimal, and silver is effectively eliminated by the liver and kidneys .
Allergic Reactions
Silver allergy is a known contraindication for the use of silver in medical devices and textiles. However, the extent of silver allergy in the general population is not well-documented.
Conclusion
While silver ions are effective antimicrobial agents, they can induce oxidative stress and cellular damage in human cells. The toxicity of silver ions is dose-dependent and can affect various cell types, including skin fibroblasts and liver cells. However, when used appropriately in medical applications, the risk of systemic toxicity is low. Understanding the mechanisms of silver ion toxicity can help in developing safer therapeutic strategies.
Sources and full results
Most relevant research papers on this topic