Microfluidic Generation of Polydopamine Gradients on Hydrophobic Surfaces.

Engineered surface-bound moleculargradients are of great importancefor a range of biological applications. In this paper, we fabricateda polydopamine gradient on a hydrophobic surface. A microfluidic devicewas used to generate a covalently conjugated gradient of polydopamine(PDA), which changed the wettabilty and the surface energy of thesubstrate. The gradient was subsequently used to enable the spatialdeposition of adhesive proteins on the surface. When seeded with humanadipose mesenchymal stem cells, the PDA-graded surface induced a gradientof cell adhesion and spreading. The PDA gradient developed in thisstudy is a promising tool for controlling cellular behavior and maybe useful in various biological applications. [ABSTRACT FROM AUTHOR]