Device fabrication and integration with photodefinable microvalves for protein separation

Plastic microfluidic devices were fabricated with an array of microvalves for two-dimensional protein separation. The devices were made by compression molding, a technique in which plastic resin is introduced into an open mold and formed under heat and pressure. The mold was created, via electroplating, from a silicon or glass master fabricated by photolithography. The fidelity in the pattern transfer from the master, through the mold, to devices was confirmed by the reproduction of channel depth and nanostructures on channel walls, and was independent of the molding temperature and compression force over the range of conditions investigated. An array of microvalves was created at the intersections of orthogonal channels by photodefinable, in situ gel polymerization; these valves enable the introduction of two types of separation media into orthogonal channels for performing two-dimensional protein separation in a microfluidic device. We demonstrated the utility of the device by separating proteins using the mechanism for the first dimension, isoelectric focusing.