The ongoing market introduction of nanoparticluated products has triggered studies on nanoparticles toxicity. Unfortunately very little is known about how particles interact with living cells and the resulting consequences for material safety and toxicity. Adsorbed proteins on the surface of nanoparticles play an important role for their behavior, i.e. agglomeration in liquid environment. Given the small size and the high specific surface of nanoparticles, protein coatings on the particles should therefore be investigated prior to further toxicological studies. The present contribution therefore focuses on the quantitative protein adsorption on the surface of nanoparticles at physiological conditions using ceria nanoparticles. Implication of protein adsorption on the quantitative uptake of nanoparticles in cells is discussed in view of oxide nanoparticles cytotoxicity and potential uptake mechanism.

References:

L.K Limbach, Y. Li, R.N. Grass, T.J. Brunner, M.A. Hintermann, M. Muller, D. Gunther, W.J Stark, Oxide nanoparticle uptake in human lung fibroblasts: Effects of particle size, agglomeration, and diffusion at low concentrations. Environmental Science & Technology 39, 9370-9376 (2005).

T.J. Brunner, P. Wick, P. Manser, P. Spohn, R.N. Grass, L.K. Limbach, A. Bruinink, W.J. Stark, In vitro cytotoxicity of Oxide Nanoparticles: Comparison to Asbestos, Silica, and effects of particle solubility. Environmental Science & Technology (2006), published online, 2006, DOI: 10.1021/es052069i

Figure 1: Stability of different oxide nanoparticles against agglomeration displayed by the zeta-potential. In ultra-pure water (empty columns) the colloid stability is characteristic for different materials. Suspensions in cell culture medium undergo protein adsorption which results in comparable low surface charge density (below -25 mV) and favor rapid agglomeration as observed for ceria.