Polymer-based microfluidic devices for biomedical applications

Two types of microfluidic bioanalytical systems were designed and fabricated in polymer substrates using the LIGA process. A continuous flow polymerase chain reaction (CFPCR) microfluidic device was fabricated in polycarbonate (PC), which utilized isothermal zone and shuttling the sample through each zone to achieve amplification. A 20-cycle PCR amplification of a fragment of a plasmid DNA template was achieved in 5.3 min. The results were comparable to those obtained in commercial laboratory-scale PCR system. The second system consisted of a microchip contating a low-density array assembled into the microfluidic channel, which was hot-embossed in poly(methyl methacrylate) (PMMA). The detection of low-abundant mutations in gene fragments (K-ras) that carry point mutations with high diagnostic value for colorectal cancer was successfully performed. The array was accessed using microfluidics in order to enhance the kinetics associated with hybridization.