Directional migration of vascular smooth muscle cells guided by synergetic surface gradient and chemical pattern of poly( ethylene glycol) brushes

Directional migration of cells in vitro can mimic corresponding biological events in vivo, which provides a way to determine the cascade responses in the tissue regeneration process and develop novel criteria for the design of tissue-inductive biomaterials. In this work, a density gradient of methoxy poly(ethylene glycol) brushes (from 0.37 to 0.95 chains/nm(2)) on plain and striped pattern surfaces was fabricated, using a dynamically controlled reaction process, and characterized by X-ray photoelectron spectroscopy and quartz crystal microbalance with dissipation. Adhesion and migration behavior of vascular smooth muscle cells were studied on the gradient and gradient-patterned surfaces. The vascular smooth muscle cells exhibited preferential orientation and enhanced directional migration on the gradient surface toward the lower end of the methoxy poly(ethylene glycol) density. By introducing methoxy poly(ethylene glycol) chemical striped patterns in parallel with the gradient direction on the surface, the extent of cell orientation and directional migration were significantly improved. Due to the synergetic effects of surface methoxy poly(ethylene glycol) striped patterns and gradient cues, almost all cells were oriented, and 67% of the cells were observed to move unidirectionally.