Abstract
Copper oxide nanoparticles with different shapes were used to examine the effect of shape on the various physicochemical properties (reactivity, aggregation, suspension stability) and to examine the behaviour by which CuO nanoparticles exhibit their biological response towards alveolar type-I cells. The different shapes examined in this study include spherical-, rod- and spindle-shaped platelet particles. In vitro dissolution studies (7 days) in 1 mM NaNO3 matrix showed a marked difference in dissolved Cu release between the nanoparticles. However, in serum-free cell-culture media (exposure media to cells), the particles' dissolution was found to be significantly enhanced with close to complete dissolution reported for all particle types. Biological studies showed both shape and size of the CuO nanoparticles tested to have a significant effect on TT-1 cell viability and release of pro-inflammatory cytokines IL-6 and IL-8. This study shows a complex interplay between particulate and dissolved species triggering the biological response. Upon immediate exposure of CuO nanoparticles of different shapes, the particulate form contributes towards the toxicity. However, for any biological response observed over and beyond a period of 24 h, the dissolved fraction becomes significant.
Acknowledgements
The research leading to these results has received funding from the QNano Project (for the work of SKM and AD) http://www.qnano-ri.eu from the European Community Research Infrastructures under the FP7 Capacities Programme FP7/2007-2013 under grant agreement no 262163 and NanoReTox (for the work of SN and DB) from the European Community's Seventh Framework Programme (NanoRetox-FP7/2007-2013) under grant agreement no CP-FP 214478-2.