The effect of environmental factors on the response of human corneal epithelial cells to nanoscale substrate topography

Abstract

We have previously shown that human corneal epithelial cells sense and react to nanoscale substrate topographic stimuli [Teixeira AI, Abrams GA, Bertics PJ, Murphy CJ, Nealey PF. Epithelial contact guidance on well-defined micro- and nanostructured substrates. J Cell Sci 2003;116(10):1881-92; Karuri NW, Liliensiek S, Teixeira AI, Abrams G, Campbell S, Nealey PF, et al. Biological length scale topography enhances cell-substratum adhesion of human corneal epithelial cells. J Cell Sci 2004;117(15):3153-64]. Here we demonstrate that cellular responses to nanoscale substrate topographies are modulated by the context in which these stimuli are presented to cells. In Epilife medium, cells aligned preferentially in the direction perpendicular to nanoscale grooves and ridges. This is in contrast to a previous study where cells cultured in DMEM/F12 medium aligned in the direction parallel to nanoscale topographic features [Teixeira AI, Abrams GA, Bertics PJ, Murphy CJ, Nealey PF. Epithelial contact guidance on well-defined micro- and nanostructured substrates. J Cell Sci 2003;116(10):1881-92]. Additionally, cell alignment in Epilife medium was dependent on pattern pitch. Cells switched from perpendicular to parallel alignment when the pitch was increased from 400 to 4,000 nm. There was a transition region (between 800 and 1,600 nm pitch) where both parallel and perpendicular alignments were favored compared to all other cellular orientations. Cells formed focal adhesions parallel to the substrate topographies in this transition region. On the nano- and microscale patterns, 400 and 4,000 nm pitch, focal adhesions were almost exclusively oriented obliquely to the topographic patterns.

Hierarchical wrinkling patterns

“…Although previous works suggest that filopodia can feel variations of surface topography, many contradictory results on the alignment of filopodia have been reported. 32 In light of this, our observations suggest that alignment of filopodia may be preferentially driven by nanoscale topographic features, whereas microscale patterns are necessary to permit filopodia attachment.…”

Determinants of cell–material crosstalk at the interface: towards engineering of cell instructive materials

“…Yet, this general trend in some cases is dependent on cell type, material properties and culturing conditions. For example, Teixeira et al [76] demonstrated that epithelial cells cultured on narrow ridges (70 nm and 400 nm pitch) can assume a spindlelike morphology parallel or orthogonal to the pattern direction, according to the culturing conditions. The molecular mechanisms governing cell alignment are not fully characterized, although it is hypothesized that filopodial activity perpendicular to the pattern direction is decreased owing to unfavoured stress tension [77].…”

Nanotechnology in regenerative medicine: the materials side

“…Microtopography influences cell adhesion, proliferation and differentiation [1,2] and, more recently, it has become clear that nanotopography also guides cell behaviour greatly [3,4]. In some applications, in which guiding the cell orientation is essential to achieve a functional tissue, such as for tendons, nerves, corneal stroma and intervertebral-disc regeneration, contact guidance of cells by micro-and nano-topographical patterns is a promising perspective [5,6]. Chemical cues in the form of various different biomolecules (nanometre scale), such as adhesive protein or growth factors, also influence cell behaviour crucially.…”