ABSTRACT
Objective: Nanosilver has numerous applications in medicine due to its potent antibacterial activity. However, data regarding the bio-safety of its effective concentrations is scarce. This study aims to assess the toxicity of silver nanoparticles on human gingival epithelial cells under in-vitro conditions
Methods: This in vitro study evaluated the toxic effects of filtered and unfiltered nanosilver solution on human gingival epithelial cells obtained from the Pasteur Institute of Iran using the methylthiazol tetrazolium bromide [MTT] assay [mitochondrial function]and membrane leakage of lactate dehydrogenase [LDH] at 24, 48 and 72h time points. The concentrations of silver nanoparticle solution used were 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 20 and 50micro g/ml
Results: The MTT assay showed that nanosilver solution at high concentrations [20 and 50micro g/ml] significantly decreased the viability of cells at all time points. The lower non-fatal concentrations at 24 and 48h were capable of causing cell death or significantly inhibit cell growth at 72h. The LDH assay demonstrated that death of epithelial cells only occurs at high concentrations of nanosilver [20 and 50micro g] and no significant toxicity was seen at lower concentrations
Conclusion: Based on the results, silver nanoparticles have toxic effects on human gingival epithelial cells and this effect is time and dose-dependent
ABSTRACT
The antimicrobial activity of silver nanoparticles has been investigated in medical fields in recent years, but there are few studies regarding its effect on oral microorganisms. The aim of the present study was to evaluate the in vitro antimicrobial and toxicity properties of nanosilver against two dental plaque microorganisms and Human Gin-gival Fibroblast [HGF] cell line. Antibacterial effects of nanosilver colloidal solution were determined by minimal inhibitory concentration [MIC] and minimal bactericidal concentration [MBC] using microdilution method. Standard strains of Streptococcus sanguis and Actinomyces viscosus were used. For toxicity assessment, MTT and LDH tests were performed under controlled conditions. Different concentrations of nanosilver were prepared and their toxic effects on HGF were determined after 24, 48 and 72 hours. The MIC of nanosilver solution for S. sanguis and A. viscosus were 16 and 4 microg/ml, respectively. The MBC of nanosilver was 64 microg/ml for S. sanguis and 16 microg/ml for A. viscosus. MTT results showed that after 24 hours the concentrations of > 0.5 microg/ml of nanosilver solution affected cell viability when compared with control group. After 48 and 72 hours only the concentration of > 5 microg/ml showed significant effect on cultured cell viability. LDH release test demonstrated toxic effect only after 48, 72 hours by 20 and 50 microg/ml of nanosilver. The results demonstrated that beside its antibacterial activity against S. sanguis and A. viscosus, nanosilver mediated a concentration and time dependent cytotoxicity on HGF