Technique for Microfabrication of Polymeric-Based Microchips from an SU-8 Master with Temperature-Assisted Vaporized Organic Solvent Bonding

Novel means of fabricating polymeric microfluidic devices are presented. An SU-8 master is applied in two-stage embossing, followed by vaporized organic solvent bonding. The primary master is created by standard photolithography; the inexpensive SU-8 primary master is used in a two-stage process to generate microfeatures in hard polymers. A vaporized solvent bonding technique that readily produces complete microfluidic chips, without the need of a sacrificial layer to prevent channel deformation, was used to form complete multilayer microfluidic devices. This technique provides a more direct method to generate hard polymer microfluidic chips than classical techniques and therefore is highly amenable to rapid prototyping. The technique lends itself readily to many polymers, facilitating device production for a variety of applications, even permitting hybrid polymer chips, and provides a rapid, cost-effective, simple, and versatile approach to the production of polymer-based microdevices. The fabrication technique was tested to build microchips to perform several analyses, including chromatographic separations and a quantitative indicator assay. High separation efficiencies of 10 000-45 000 plates/m were obtained using the fabricated liquid chromatography (LC) microchip. The fabrication method was also tested in building a passive micromixer that contained high-density microfeatures and required three polymer layers. A glycine assay using o-phthaldaidehyde (OPA) was performed in the micromixer. With glycine concentrations ranging from 0.0 to 2.6 mu M, a linear calibration plot was obtained with a detection limit of 0.032 mu M.