Influence of surface roughness on neural differentiation of human induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) own the capacity to develop into all cell types of the adult body, presenting high potential in regenerative medicine. Regulating and controlling the differentiation of iPSCs using the surface topographic cues of biomaterials is a promising and safe approach to enhance their therapeutic efficacy. In this study, we tested the effects of surface roughness on differentiation of human iPSCs into neural progenitor cells and dopaminergic neuron cells using polystyrene with different roughness (R0: flat surface; R1: rough surface, Rq ∼ 6 μm; R2: rough surface, Rq ∼ 38 μm). Neural differentiation of human iPSCs could be influenced by surface roughness. Up-regulated neuronal markers were found in cells on rough surface, as examined by real-time PCR and immunostaining. Particularly, the R1 surface significantly improved the neuronal marker expression, as compared to R0 and R2 surface. This study demonstrates the significance of surface roughness, depending on the roughness level, in promoting differentiation of human iPSCs towards the neuronal lineage. Our study suggests the potential applications of surface roughness in iPSCs based treatment of neural disorder diseases, and highlights the importance of design and development of biomaterials with effective surface structures to regulate stem cells.