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Toxicity Assessment of Six Titanium Dioxide Nanoparticles in Human Epidermal Keratinocytes
Monteiro-Riviere, N., L. Zhang, AND B. Veronesi. Toxicity Assessment of Six Titanium Dioxide Nanoparticles in Human Epidermal Keratinocytes. Presented at Society of Toxicology, Phoenix, AZ, March 23 - 27, 2014.
This is a continuation of ORD research examining the influence of physicochemical properties on nanoparticle penetration through biological barriers.
Toxicity Assessment of Six Titanium Dioxide Nanoparticles in Human Epidermal Keratinocytes Nanoparticle uptake in cells may be an important determinant of their potential cytotoxic and inflammatory effects. Six commercial TiO2 NP (A=Alfa Aesar,10nm, A*=Alfa Aesar 32nm, B=P25 27.5nm), (C=Acros 200 nm), (C*=NanoAmor 30-40nm) and (D*=Mkano 200-400nm) and controls were assessed for their size, effect on cell viability, agglomeration, cytokine release, and cellular uptake in human epidermal keratinocytes (HEK). TiO2 NP were suspended in water or in culture medium, and characterized by transmission electron microcopy (TEM) and dynamic light scattering (DLS). TiO2 NP did not change shape with any NP type in medium by TEM but DLS showed an increase in size and in agglomerations. TiO2 NP were assessed for viability with CellTiter 96® AQueous One (96AQ), MTT and alamar Blue (aB) assays. All NP interfered with 96AQ and MTT but aB was minimal. Therefore, aB assay was selected to assess all NP in serial dilutions ranging from 0.0125 to 0.4mg/ml for 24h. Only TiO2 sample B had a statistically significant decrease in aB viability at 0.4mg/ml. Also, interleukin (IL)-1β, IL-6, IL-8, IL-10, and TNF-α were evaluated and slight increases were noted in samples A, A*, C, D* at medium or high concentrations, while A* and B showed an increase in IL-6. IL-10 and IL-1B release was noted for all NP but was at or below the detection limit. A significant decrease in IL-8 was noted for all NP at the highest concentrations which demonstrates assay interference except for sample C. All NP were localized within the intracellular cytoplasmic vacuoles of HEK and the element titanium (Ti) was detected and confirmed by energy-dispersive x-ray spectroscopy (EDX) analysis. In conclusion, based on cell viability only sample B was slightly cytotoxic to HEK and samples B and A* have the potential to cause inflammation indicated by an increase in IL-6. Disclaimer: This is an abstract or a proposed presentation and does not necessarily reflect EPA policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.