Preparation of gelatin density gradient on poly(ε-caprolactone) membrane and its influence on adhesion and migration of endothelial cells.

Directional migration of endothelial cells (ECs) can be achieved by gradient cues in vitro, which mimics the corresponding biological events in vivo. Currently, most of the gradients have been prepared on model surfaces which are too simple compared to real degradable biomaterials. In this study, the amino group density gradient was prepared on poly(ε-caprolactone) (PCL) membrane surface by a gradient aminolysis method, which was transferred into gelatin density gradient by covalent linking with glutaraldehyde. The resulted gelatin density gradient ranged from 0.49 to 1.57μg/cm(2) on the PCL membrane. The adhesion, orientation and migration of ECs on the PCL membrane with the gelatin density gradient were studied. The ECs showed preferred orientation and directional migration toward the gradient direction with enhanced gelatin density at proper position (gelatin density), forwarding a new step toward the preparation of applicable gradient biomaterials in tissue regeneration.