Modulation of Neural Differentiation through Submicron-Grooved Topography Surface with Modified Polydopamine.

Surface topography and bioactive molecules can generate physicochemical cues that control proliferation and differentiation of neural cells. In this study, polystyrene (PS) submicron-patterns with different widths (400 and 800 nm) and depths (100 and 400 nm) were prepared and subsequently modified with polydopamine (PDA) by a coating method. We examined neurites of PC12 cells and human adipose-derived stem cells (hADSCs) incubated in neuronal induction medium containing nerve growth factor (NGF) and basic fibroblast growth factor (bFGF), respectively. Then the differentiated cells on different grooved topographies were immunologically stained by Tuj-1 (a neuron marker) to compare the extent of neuronal differentiation. Our results showed that PC12 cells on grooved topography have predominantly bipolar neurite extension and align along the direction of the patterns, while flat surface has multipolar neurites. We demonstrated that the depths of topography have a strong impact on neurite outgrowth and alignment. In terms of the number of neurites, neurite length, and percentage of Tuj-1 positive cells, the 400/400 and 800/400 nm (widths/depths) PS grooves are appropriate for the cultivations of PC12 cells and hADSCs relative to those of other groups. In conclusion, the submicron-grooved topography and neurotrophic growth factors supported neurites outgrown and differentiated into neuron-like cells.