The fate of silica based Stober particles soaked into growth media (RPMI and M254): A DLS and ζ-potential study

Understanding the mechanisms involved in the interaction of biological systems with inorganic materials is of great importance and interest in both fundamental and applied disciplines in several different fields such as astrobiology, ecology, biology, biotechnology, engineering, and medicine. In this context, this paper investigates the interaction of biomacromolecules with submicrometric silica gel particles (NP) obtained through the Stober method. Surprisingly, particles size reduction is observed after their dispersion into two different reconstituted growth media (RPMI and M254). This effect was related to the nature of the Stober particles and the mechanism of their formation. The experimental results can be explained arguing that a biomacromolecule corona rapidly forms on NP incubated in both RPMI and M254 growth media. The results suggest that hydrolytic attack at incompletely condensed internal surface valence sites as well as interactions between NPs surface and the components of the growth media reverse the aggregation process, giving smaller dis-aggregated particles surrounded by a biomacromolecule corona. Moreover it was assessed that, at longer incubation time, the particles slightly grow probably due to interlocking of biomacromolecules in the corona. Furthermore, experimental results confirm that formation of this corona is a competitive and dynamic process. The present paper shows that the described effects (as size changes) are strongly dependent on the nature of the growth medium. (c) 2015 Elsevier B.V. All rights reserved.