Hand-held, fully automated microfluidic systems have been developed and characterized to perform a magnetic bead-based biochemical immunoassay. The magnetic beads were coated with a polymer on which a dendritic antibody had been prepared to form the basis of a "sandwich" immunoassay for sensing biomolecules. With the press of a button, a complete immunoassay is performed to detect biohazards, and the result of the assay is displayed on a LCD. One system was made by using biocompatible silicone tubing for interconnections between the devices while another system was fabricated on a micromachined "glass-on-silicon" motherboard (Dharmatilleke et al.,. 2000). The first system consists of four collapsilbe reservoirs for reagent storage, made of very thin biocompatible Teflon~(TM); and array of zero dead volume pinch valves; two magnetic curtain magnetic particle separators; a micro wire electrode or IDA for detection; a flow sensor, a valveless rotary pump to pull the reagents through the miicrofluidic system and associated eletronics. On the second system, the mini pinhc valves have been replaced by "collapshible" membrane type zero dead volume valves and pumping is by peristaltic operation of the valves. This work preceeds the next step, which is an all-MEMS system "on-a-chip".
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