Femtosecond laser-drilled capillary integrated into a microfluidic device

Recent growth in microfluidic technology is, to a large extent, driven by soft lithography, a high-throughput fabrication technique where polymer materials, such as poly(dimethyl) siloxane (PDMS), are molded to form microscopic channel networks. Nevertheless, the channel architectures that can be obtained by molding are limited. We address this limitation by using femtosecond laser micromachining to add unmoldable features to the microfluidic devices. We apply laser ablation to drill microcapillaries, with diameters as small as 0.5 mu m and aspect ratios as high as 800:1, in the walls of molded PDMS channels. Finally, we use a laser-drilled microcapillary to trap a polystyrene bead by suction and hold it against a shear flow. (c) 2005 American Institute of Physics.