Visible-light reduced silver nanoparticles' toxicity in Allium cepa test system

Area of Science:

• Environmental Science
• Nanotechnology
• Plant Toxicology

Background:

• Silver nanoparticles (AgNPs) are prevalent in consumer goods for their antibacterial qualities.
• Concerns exist regarding AgNP environmental release and potential toxicity.
• Limited knowledge on AgNP aggregation behavior necessitates further investigation.

Purpose of the Study:

• To investigate the toxicity of uncoated (uc-AgNP) and polyvinylpyrrolidone-coated (PVP-AgNP) silver nanoparticles.
• To assess AgNP toxicity under both dark and visible-light conditions.
• To evaluate the impact of low AgNP concentrations on the plant system Allium cepa.

Main Methods:

• Allium cepa seeds were exposed to varying concentrations of uc-AgNP and PVP-AgNP (0.5-100 ng/mL).
• Toxicity endpoints evaluated included seed germination, root development, genotoxicity, and biochemical alterations.
• Experiments were conducted under both dark and visible-light conditions.

Main Results:

• AgNPs did not induce acute toxicity (germination/root inhibition) but caused genotoxicity and oxidative stress.
• Visible light exposure significantly reduced AgNP-induced genotoxicity (chromosomal aberrations, micronuclei).
• Cytotoxicity and morphoanatomical changes were observed only in the dark at higher concentrations, indicating light mitigates toxicity.

Conclusions:

• Silver nanoparticles exhibit genotoxic and cytotoxic effects on Allium cepa roots even at low concentrations.
• Visible light exposure alters AgNP aggregation, reducing their overall toxicity.
• Visible light presents a potential method for remediating AgNP residues and minimizing environmental risks.