Flow Through Gels as a Tool to Generate 3D Concentration Profiles in Hydrogel-Filled Devices

Laminar flow patterning is an iconic microfluidic technology used to locally deliver chemicals to specific regions on a two-dimensional surface with high spatial fidelity. Here we present a novel extension of this technology by flow patterning inside cured, three-dimensional (3D) hydrogels. We control the pressures at the inlets to shape the size and position of a region of high solute concentration in the main channel filled with a cured collagen 1 hydrogel. This method allows solutes to be delivered with 50 micron accuracy within the gel, as evidenced by control of concentration profiles of 40 kDa fluorescent dye.