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Highly Flexible Platform for Tuning Surface Properties of Silica Nanoparticles and Monitoring Their Biological Interaction

Ojea-Jiménez, Isaac, Urbán, Patricia, Barahona, Francisco, Pedroni, Matteo, Capomaccio, Robin, Ceccone, Giacomo, Kinsner-Ovaskainen, Agnieszka, Rossi, François, Gilliland, Douglas
ACS applied materials 2016 v.8 no.7 pp. 4838-4850
amino acids, cell culture, culture media, cytotoxicity, epithelial cells, humans, monitoring, nanoparticles, particle size, physicochemical properties, silica
The following work presents a simple, reliable and scalable seeding-growth methodology to prepare silica nanoparticles (SiO₂ NPs) (20, 30, 50 and 80 nm) directly in aqueous phase, both as plain- as well as fluorescent-labeled silica. The amount of fluorescent label per particle remained constant regardless of size, which facilitates measurements in terms of number-based concentrations. SiO₂ NPs in dispersion were functionalized with an epoxysilane, thus providing a flexible platform for the covalent linkage of wide variety of molecules under mild experimental conditions. This approach was validated with ethylenediamine, two different amino acids and three akylamines to generate a variety of surface modifications. Accurate characterization of particle size, size distributions, morphology and surface chemistry is provided, both for as-synthesized particles and after incubation in cell culture medium. The impact of physicochemical properties of SiO₂ NPs was investigated with human alveolar basal epithelial cells (A549) such as the effect in cytotoxicity, cell internalization and membrane interaction.