Fabrication of Gradient Hydrogels Using a Microfluidics/ Photopolymerization Process

Author(s): Burdick, Jason A., Ali Khademhosseini, Robert Langer

Journal: Langmuir (2004) 20(13): 5153-5156.

Abstract:
A method of fabricating photo-cross-linked hydrogels with gradients of immobilized molecules and crosslinking densities is introduced. Two macromer/initiator solutions are injected into a unique poly-(dimethylsiloxane) channel system that produces a prepolymer gradient that is subsequently polymerized into a water-swollen hydrogel with ultraviolet light exposure. The gradient is controlled by the injection flow rate (optimized to 0.3 µL/min per inlet to produce a linear gradient). The technique is investigated both through fabrication of adhesive ligand gradients that modulate spatial distribution of attached endothelial cells and gradients of cross-linking densities that led to unique hydrogel architectures and spatially dependent swelling.