The Cytotoxic Effect of Silver Nanoparticles on Human Lung Cells

Overview

The recent influx of innovation in the nanotechnology industry has drastically increased the concentration of airborne nanoparticles in the air, with silver nanoparticles (AgNPs) making up approximately a quarter (~$2.5 bn.) of the industry. It is estimated that about 14% of inventoried silver nanotechnology products (e.g., silver- embedded textiles, household appliances, biomedical devices) could potentially aerosolize AgNPs during usage. Additionally, AgNPs have been shown to penetrate deeply into the alveolar region, but their effects on this region are not well studied. In this experiment, it was hypothesized that AgNPs would cause cellular cytotoxicity based on a literature search. A549 human alveolar epithelial lung cells were exposed to concentrations of 60 nm AgNPs between 0 and 2.5 µg/mL. Cell counts, a trypan blue viability assay, and photomicrographs were taken every 24 hours over a 72-hour period. The results indicated a significant decrease in the cell population (F(5, 24) = 3.508; p = 0.0160) and viability (F(5,24) = 6.953; p = 0.0004), supporting the hypothesis about AgNPs' cytotoxic nature. The morphological effects suggested cell death (intracellular vacuoles) and possible inflammation at higher concentrations (>1.5 μg/mL). These results indicate that inhaled AgNPs may pose a serious health hazard to the human lungs because they damage the one-cell thick epithelial layer of the lungs. Long-term effects may include an increased risk of lung cancer, asthma, and COPD. Future research should test longer exposure periods and confirm the presence of inflammation by testing for pro-inflammatory cytokines.