(241b) Post-Script Fabrication of Bioseparation Membranes within Sealed, Completed Microfluidic Devices

In recent years, there has been an effort to develop self-calibrating electrochemical and optical biosensors that require minimal human intervention. Separation membranes are structural elements that will feature prominently on many of these biosensors, and fabrication techniques which allow for the formation of membranes in sealed channels are especially interesting. Membranes polymerized in completed microchannels can form tight seals between the floor and ceiling, especially if these surfaces have been chemically modified. Additionally, if membranes are synthesized before the microchannels are sealed, the wafer bonding process used to seal the channel may require temperatures that are not amenable to the membrane materials, particularly if functionalization with biomolecules is used. Traditional photolithographic methods which employ photomasks suffer from several disadvantages brought about by the long working distance between mask and membrane precursor solution due to the thickness of the capping wafer. In this work, we detail the fabrication of membranes in completed, sealed microchannels through the use of a novel ?post-script? procedure which uses on-chip photomasks.