Effect of topography parameters on cellular morphology during guided cell migration on a graded micropillar surface

Purpose: Guided cell migration refers to the engineering of local cell environment to specifically direct cell migration and has important applications such as utilization in cell sorting and wound healing assays. Graded micropillar surfaces have been utilized for achieving guided cell migration. Topographic parameters such as micropillar diameter and spacing gradient may have effects on the morphology of attached cells. It is critical to understand this interaction between the cells and the underlying microscale structures. Methods: In this study, a graded micropillar substrate has been fabricated to investigate the effects of the microtopography on the cell morphology in terms of the cell aspect ratio and cell circularity. Results: It is found that 1) with the increase of the micropillar diameter, the cell aspect ratio has no significance change. At the small spacing gradients, the aspect ratio is smaller than that at the large spacing gradients; 2) statistical analysis shows both the micropillar diameter and spacing gradient have no significant effect on the cell aspect ratio compared to the flat surface; 3) the cell circularity at the small micropillar diameters is higher than that at the large micropillar diameters. The cell circularity at the micropillar gradient of 0.1 µm is higher than those at the other micropillar gradients; and 4) three microtopographic conditions are considered to have statistically significant effect on the cell circularity compared to the flat surface, including the micropillar diameters of 5 µm and 10 µm and the spacing gradient of 0.1 µm.