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Title: Interactions of silver nanoparticles with primary mouse fibroblasts and liver cells

Primary cells are ideal for in vitro toxicity studies since they closely resemble tissue environment. Here, we report a detailed study on the in vitro interactions of 7-20 nm spherical silver nanoparticles (SNP) with primary fibroblasts and primary liver cells isolated from Swiss albino mice. The intended use of silver nanoparticles is in the form of a topical antimicrobial gel formulation for the treatment of burns and wounds. Upon exposure to SNP for 24 h, morphology of primary fibroblasts and primary liver cells remained unaltered up to 25 {mu}g/mL and 100 {mu}g/mL SNP, respectively, although with minor decrease in confluence. IC{sub 50} values for primary fibroblasts and primary liver cells as revealed by XTT assay were 61 {mu}g/mL and 449 {mu}g/mL, respectively. Ultra-thin sections of primary cells exposed to 1/2 IC{sub 50} SNP for 24 h, visualized under Transmission electron microscope showed the presence of dark, electron dense, spherical aggregates inside the mitochondria, and cytoplasm, probably representing the intracellular SNP. When the cells were challenged with {approx} 1/2 IC{sub 50} concentration of SNP (i.e. 30 {mu}g/mL and 225 {mu}g/mL for primary fibroblasts and primary liver cells, respectively), enhancement of GSH ({approx} 1.2 fold) and depletion of lipid peroxidation ({approx} 1.4more » fold) were seen in primary fibroblasts which probably protect the cells from functional damage. In case of primary liver cells; increased levels of SOD ({approx} 1.4 fold) and GSH ({approx} 1.1 fold) as compared to unexposed cells were observed. Caspase-3 activity assay indicated that the SNP concentrations required for the onset of apoptosis were found to be much lower (3.12 {mu}g/mL in primary fibroblasts, 12.5 {mu}g/mL in primary liver cells) than the necrotic concentration (100 {mu}g/mL in primary fibroblasts, 500 {mu}g/mL in primary liver cells). These observations were confirmed by CLSM studies by exposure of cells to 1/2 IC{sub 50} SNP (resulting in apoptosis) and 2x IC{sub 50}) cells (resulting in necrosis). These results clearly suggest that although silver nanoparticles seem to enter the eukaryotic cells, cellular antioxidant mechanisms protect the cells from possible oxidative damage. This property, in conjunction with the finding that primary cells possess much higher SNP tolerance than the concentration in the gel ({approx} 20 {mu}g/g), indicates preliminary safety of the formulation and warrants further study for possible human application.« less
Authors:
; ;  [1] ;  [2]
  1. Centre for Nanobioscience, Agharkar Research Institute, G.G. Agarkar Road, Pune 411004 (India)
  2. Centre for Nanobioscience, Agharkar Research Institute, G.G. Agarkar Road, Pune 411004 (India), E-mail: kpaknikar@gmail.com
Publication Date:
OSTI Identifier:
21269310
Resource Type:
Journal Article
Resource Relation:
Journal Name: Toxicology and Applied Pharmacology; Journal Volume: 236; Journal Issue: 3; Other Information: DOI: 10.1016/j.taap.2009.02.020; PII: S0041-008X(09)00087-8; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 60 APPLIED LIFE SCIENCES; APOPTOSIS; FIBROBLASTS; GELS; HUMAN POPULATIONS; IN VITRO; LIVER CELLS; MITOCHONDRIA; NANOSTRUCTURES; NECROSIS; PARTICLES; SILVER; TOXICITY; TRANSMISSION ELECTRON MICROSCOPY; WOUNDS