Design, fabrication and evaluation of nanoscale surface topography as a tool in directing differentiation and organisation of embryonic stem-cell-derived neural precursors

A major limitation in the translation of stem cells technology to clinical applications is the lack of efficient control over their proliferation and differentiation. Recent in vitro research findings suggest that biomaterials with nanoscale surface topography can influence cell behaviour like adhesion, proliferation and differentiation. Therefore, the identification of biomaterials that support appropriate ES cell attachment, proliferation and differentiation into cells of interest is an attractive strategy worth investigation. In this study we present the design and fabrication of thin films of gold with surface topography of varying roughness using a combination of microfabrication techniques. We then explored their biomimetic potential to direct differentiation of ES cell-derived neural precursors. Standard glass coverslips and tissue culture plastic were used as reference materials. Our preliminary results show that ES-derived neural precursors best adhered on gold and underwent the highest differentiation on gold films with root mean square surface roughness (R-q) of 21 nm (72 +/- 6%) after five days of culture in the absence of traditional soluble neurotrophic factors. Moreover, when cells were seeded on a combination of micro-scale grooves with nanoscale surface roughness, axonal outgrowth orientation was observed to be influenced by the grating axis. This data identifies gold as a potential biomaterial candidate with suitable cytocompatibility for ES cell research. It further lends support to the hypothesis that biomaterial design may optimize ES cell-derived neural differentiation and organisation. This may find utility as a tool to synergically complement soluble chemical factors currently used in in vitro protocols for the stimulation and modelling of ES differentiation. Ultimately, substrate patterning may hold special utility in the design of neural prostheses because repair of neurological injuries requires directional guidance. (C) 2009 Elsevier B.V. All rights reserved.