Laminated plastic microfluidic components for biological and chemical systems

Laminated plastic microfluidic components are being developed for; biologic al testing systems. and chemical sensors. Applications include a DNA therma l cycler, DNA analytical systems, electrophoretic flow systems, dialysis sy stems, and metal sensors for ground water.. This article describes fabricat ion processes developed for these plastic microfluidic components, and the fabrication of a chromium metal sensor and a microdialysis device. Most of the components have a stacked architecture; Using this architecture, the fl uid flows, or is pumped through; as many as nine laminated functional level s: Functions include pumping, mixing, reaction, detection, reservoirs, sepa rations, and electronics. Polyimide, poly(methylmethacrylate) (PMMA), and p olycarbonate materials with thickness between 25 and 125 mu m are used to c onstruct the components.This makes the components low cost, inert to many b iological fluids and chemicals; and disposable. The components are fabricat ed by excimer laser micromachining the microchannel patterns and microstruc tures in the various laminates. In some,cases, micropumps are integrated in to these components to move the fluids. Vias and interconnects are also cut by the laser and integrated. with micropumps. The laminates are sealed and bonded by adhesive and thermal processes and are leak tight. The parts wit hstand pressures as high as 790 kPa. Typical channel widths are 50 to 100 m u m; :with aspect ratios near 5. (C) 1999 American Vacuum Society. [S0734-2 101(99)06604-X].