AVS 52nd International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI1-ThM

Paper BI1-ThM2
BioMEMS Chip and Package Design for Surface-Controlled Bioreaction Processes

Thursday, November 3, 2005, 8:40 am, Room 311

Session: BioMEMS and Microfluidics
Presenter: J.J. Park, University of Maryland
Authors: J.J. Park, University of Maryland
M.A. Powers, University of Maryland
X. Luo, University of Maryland
R. Ghodssi, University of Maryland
G.W. Rubloff, University of Maryland
Correspondent: Click to Email
BioMEMS research exploiting multi-step, multi-site biomolecular reactions for metabolic engineering and other applications requires an integrated chip, packaging, and control system designs to accommodate fluidic, electrical, and optical networks. We have developed approaches for sealing and re-opening bioMEMS systems to allow reuse and post-process analysis. Photoimageable SU-8 is used on pyrex wafers to create microfluidic channels as micro-knife-edges for sealing to flexible PDMS gaskets. Electrical networks provide Au and ITO electrodes for selective assembly and functionalization of amine-rich chitosan as the platform for biomolecular reaction steps, while integrated SU-8 waveguides enable fluorescence sensing at these sites. PDMS is spun onto a Plexiglas top wafer, inverted, and placed onto the SU-8 channels. The two wafers are then compressed by bolting together a Plexiglas package comprised of top and bottom plates, along with a Plexiglas ring which carries the inputs and outputs to external control systems. The design enables optical microscopy observations from above, which confirm leak-free sealing when colored dye is transported through the microfluidic network. Chitosan polysaccharide, positively charged in low pH solution, is electrodeposited at negative electrodes in the bioMEMS system. This provides a promising avenue for extending to bioMEMS environments our prior work using patterned electrodes on chips in solution, which included selective conjugation of proteins and nucleic acids, as well as enzymatic conversion of small molecules.