Hydrogel-based capillary flow pumping in a hydrophobic microfluidic channel

In this study, we propose a novel method to generate a capillary pressure-driven flow in a microchannel with a hydrophobic surface. The microfluidic device has a wide channel in which a hydrogel pillar array is embedded. The hydrogel pillar array was formed in the microchannel by a photopolymerization process. The flow rate due to a capillary action was strongly dependent on the distance between the pillars. Moreover, our capillary pumping with a hydrogel pillar array sustained the flow for more than 5 min with a limited sample volume. Our microfluidic device provides two advantages: (1) the modification of the polymer surface to make it hydrophilic is not required and (2) the conventional polymer molding technique can be applied to produce microfluidic devices, instead of the precision molding technique. The results indicate the possible fabrication of various microfluidic chip devices that can be easily implemented in point-of-care diagnostics. (C) 2014 The Japan Society of Applied Physics