Influence of Serum Supplemented Cell Culture Medium on Colloidal Stability of Polymer Coated Iron Oxide and Polystyrene Nanoparticles With Impact on Cell Interactions In Vitro

When nanoparticles interact with cells, the possible cellular responses to the particles depend on an array of parameters, in both particle and biological aspects. On the one hand, the physicochemical properties of the particles (e.g., material, size, shape, and surface charge) are known to play a key role in particle-cell interactions. On the other hand, it has been shown that prior to coming into contact with cells, nanoparticle interaction with the surrounding biological fluid may lead to a change of the initial particle properties. For example, the colloidal behavior of nanoparticles is strongly influenced by the density and viscosity of the surrounding media in both in vitro and in vivo systems. In this study, we demonstrate how the surface charge and composition of different nanoparticles can impact upon their physicochemical characteristics, such as their colloidal stability, within a representative biological fluid and how the change of these parameters can significantly influence the subsequent cellular interaction in vitro. Therefore, we compared charged polymer coated superparamagnetic iron oxide nanoparticles to polystyrene nanoparticles of different surface charges. Particles of lower colloidal stability, namely positively charged superparamagnetic iron oxide nanoparticles, and the polystyrene nanoparticles, showed a higher cell-penetration in vitro than the colloidally stable particles.