The effect of silica nanoparticulate coatings on serum protein adsorption and cellular response.

Serum protein adsorption on colloidal silica surfaces was investigated using a quartz crystal microbalance with dissipation (QCM-D) monitoring. The amount of serum proteins adsorbed on colloidal silica-coated surfaces was not significantly different from the control silica surfaces, with the exception of 21nm colloidal silica which experienced significantly less (P<0.05) fibrinogen adsorption compared with control silica. The adhesion and proliferation of human endothelial cells (C11STH) on nano-scale colloidal silica surfaces were significantly reduced compared with control silica surfaces, suggesting that the conformation of adsorbed proteins on the colloidal silica surfaces plays a role in modulating the amount of cell binding. Fibronectin is one of the main extracellular matrix proteins involved in endothelial cell attachment to biomaterial surfaces. There was reduced binding of a monoclonal anti-fibronectin antibody, that reacted specifically with the cell-binding fragment, to fibronectin-coated colloidal silica surfaces compared with control silica surfaces. This suggests that the fibronectin adsorbed on the colloidal silica-coated surfaces was conformationally changed compared with control silica reducing the availability of the cell-binding domain of fibronectin.

Effects of a nanoparticulate silica substrate on cell attachment of Candida albicans.

AIMS: To investigate the influence of silica nanoparticles on the attachment and growth of Candida albicans cells. METHODS AND RESULTS: Spherical silica nanoparticles with diameters of 4, 7, 14 or 21 nm were attached to tissue culture polystyrene by a polycationic binding layer using a simple deposition procedure. The modified surfaces were shown to reduce the attachment and growth of C. albicans cells by a range of different measurements including microscopy, staining cells and measuring the amount of dye taken up and total cell activity measured using a dye reduction assay. For those cells that did attach and grow, the nanoparticle-coated surface inhibited the yeast to hyphal transition that is induced in the presence of serum. The greatest effect was observed for 7 and 14 nm diameter silica particles and we propose that the mechanism for these effects are related to either the topography of the surface or the slow dissolution of the bound silica. CONCLUSIONS: The attachment and growth of C. albicans is reduced by surface modification with silica nanoparticles. SIGNIFICANCE AND IMPACT OF THE STUDY: The modification of surfaces by nanoparticulate coatings is a simple process that may have applications in reducing the prevalence of Candida sp. cells on medical devices thus, limiting the incidence of this pathogenic yeast in clinical environments.

The effect of silica nanoparticulate coatings on cellular response.

The current techniques used to create patterned materials at the nanometer scale such as electron beam lithography are restricted to patterning small areas, which can be expensive and time consuming. A simple, cost-effective approach has been developed to create a reproducible surface topography to influence the cellular response. In this study, the cellular response of murine fibroblasts to 7, 14 and 21 nm colloidal silica particles were investigated over one, three and seven days and up to seven weeks. The surface topography and wettability of the surfaces were also studied. The results confirmed that silica particles create a nanoscale topography, which initiates a distinctive cellular response affecting the morphology, adhesion and proliferation of the fibroblasts. The effect was evident up to seven weeks with no adverse effects on cell viability.