Optimal structural and physical properties of aerogels for promoting robust neurite extension in vitro

Cell behaviour is influenced by external factors including the physical properties of the substrate such as its surface topography and stiffness. Recent studies have demonstrated the potential of aerogels as biomaterials and specifically as neural scaffolds. The 3-D structure inherent to aerogels offers an advantage over other biocompatible substrates which lack the dimensionality needed to mimic the in vivo topography of tissues. Here, we used a variety of aerogel types to correlate the extension of neurites by neuronal cells with surface roughness ranging from 0 to 3 μm and stiffness 10 kPa-4 MPa. This investigation reveals that the optimal surface features for neurite extension are a surface roughness of 0.5 μm and a Young's modulus between 1 and 3.5 MPa. The significance of these findings to optimize materials for nerve repair is discussed.