Guided cell migration on a graded micropillar substrate

Cell migration is facilitated by the interaction of living cells and their local microenvironment. The local topography is one of the key factors regulating cell migration. Interaction between the surface topography and the cell behaviors is critical to understanding tissue development and regeneration. In this study, a dynamic mask photolithography technique has been utilized to fabricate a surface with graded micropillars. It has been demonstrated that the cells have been successfully guided to migrate from the sparse zone to the dense zone. The cell polarization angle has been characterized in both sparse zone and the dense zone. Compared to the dense zone, the cells in the sparse zone are more aligned along the direction of the micropillar spacing gradient, which enables the guided cell migration. Moreover, the effects of the micropillar spacing gradient, micropillar diameter, and micropillar height have been investigated in terms of the cell migration speed and cell spreading area. Finally, two issues significantly affecting the cell migration have been discussed: trapped cells between the micropillars and cell clusters.