Effect of sonication and serum proteins on copper release from copper nanoparticles and the toxicity towards lung epithelial cells

Pontus Cronholma, Klara Midanderb, Hanna L. Karlssona, Karine Elihnc, Inger Odnevall Wallinderb & Lennart Möller*aa Unit for Analytical Toxicology, Department of Biosciences and Nutrition at Novum, Karolinska Institutet, Stockholm, Swedenb Division of Surface and Corrosion Science, Department of Chemistry, School of Chemical Science and Engineering, Royal Institute of Technology, Stockholmc Workplace Aerosols Research Group, Department of Applied Environmental Science, Stockholm University, Stockholm, SwedenCorrespondence: Prof. Lennart Möller, Dr Med Sci, Karolinska Institutet, Biosciences and Nutrition, Novum, Huddinge, Huddinge, SE-141 57 Sweden. lennart.moller@ki.se AbstractDifferent methodological settings can influence particle characteristics and toxicity in nanotoxicology. The aim of this study was to investigate how serum proteins and sonication of Cu nanoparticle suspensions influence the properties of the nanoparticles and toxicological responses on human lung epithelial cells. This was investigated by using methods for particle characterization (photon correlation spectroscopy and TEM) and Cu release (atomic absorption spectroscopy) in combination with assays for analyzing cell toxicity (MTT-, trypan blue- and Comet assay). The results showed that sonication of Cu nanoparticles caused decreased cell viability and increased Cu release compared to non-sonicated particles. Furthermore, serum in the cell medium resulted in less particle agglomeration and increased Cu release compared with medium without serum, but no clear difference in toxicity was detected. Few cells showed intracellular Cu nanoparticles due to fast release/dissolution processes of Cu. In conclusion; sonication can affect the toxicity of nanoparticles.