Metal-oxide nanoparticles have become increasingly common in consumer products to produce desired physical properties and visual effects. While assumed to be safe, relatively little research has been done into the long term effects of nanoparticles on eukaryotic cells. My research focuses on titanium dioxide (TiO2) nanoparticles, because of their presence in personal care products, such as toothpaste, cosmetics, and sun screen, where they are often used to create a white, lustrous appearance. These products are not only applied directly to skin or ingested, but are used on a daily basis, leading to chronic exposure. Using synthetic liposomes as a model for the eukaryotic plasma membrane, we have investigated the effects of TiO2 nanoparticles on the thermal stability of phospholipid bilayers. We have used differential scanning calorimetry (DSC) to determine the transition temperature (Tm) of the phospholipid bilayers of a series of liposomes made of purified lipids, mixtures of lipids, and cellular extracts in the presence and absence of micromolar levels of TiO2 nanoparticles. Lipids tested include phospatidylethanolamine (PE), phosphatidylglycerol (PG), cardiolipin, and E.coli cellular extracts. It was found that the presence of the nanoparticles caused the Tm to increase by between five and ten percent, suggesting interactions that stabilize the membrane rather than disrupt it. Working in collaboration with another member of the lab, I am currently determining the effects of TiO2 nanoparticles at concentrations that have been shown to have mutagenic and cytotoxic effects on bacteria. This work is supported by a grant from the Defense Threat Research Agency.

Investigation of the effects of titanium dioxide nanoparticles on phospholipid bilayers using differential scanning calorimetry

249th National Meeting (2015)

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