Toxicity of gold-nanoparticles: Synergistic effects of shape and surface functionalization on micromotility of epithelial cells

Abstract

Nanoparticle exposure is monitored by a combination of two label-free and non-invasive biosensor devices which detect cellular shape and viscoelasticity (quartz crystal microbalance), cell motility and the dynamics of epithelial cell-cell contacts (electric cell-substrate impedance sensing). With these tools we have studied the impact of nanoparticle shape on cellular physiology. Gold (Au) nanoparticles coated with CTAB were synthesized and studied in two distinct shapes: Spheres with a diameter of (43 ± 4) nm and rods with a size of (38 ± 7) nm × (17 ± 3) nm. Dose-response experiments were accompanied by conventional cytotoxicity tests as well as fluorescence and dark-field microscopy to visualize the intracellular particle distribution. We found that spherical gold nanoparticles with identical surface functionalization are generally more toxic and more efficiently ingested than rod-shaped particles. We largely attribute the higher toxicity of CTAB-coated spheres as compared to rod-shaped particles to a higher release of toxic CTAB upon intracellular aggregation.

Keywords::

• ECIS
• micromotion
• TER
• D-QCM
• gold nanoparticles

Acknowledgments

For the fruitful collaboration in the cell laboratories of Mainz and Göttingen, we would like to thank Stefanie Klassen, Anja Herdlitschke, Angela Rübeling and Dr. Ingrid Schuberth.

Declaration of interest: Financial support was granted by the German Science Foundation (DFG) through the SPP 1313 Bio-Nano-Responses program (JA 963/10-1). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.