A digital dilution chip using inter-well valves controlled by a ternary microfluidic multiplexer

Abstract

We present a digital dilution chip of 2 x 6 well array that is capable of changing the dilution ratio. We mixed the diluted samples with other samples by using inter-well valves. The previous continuous and digital dilution chips diluted samples that had a fixed dilution ratio depended on the structure of the branched microchannel or the volume of the well. The present chip can perform the programmable mixing process that selectively fills, merges, and splits the identical wells by controlling the inter-well valves. Thus, the present digital dilution chip can easily change the dilution ratio without any structural change. In this study, the present chip changed the dilution ratio, such as the linear or exponential ratio, within a 4.2% dilution difference. They were then mixed with other samples within a 3.4% mixing difference. In order to reduce the number of interconnection ports that transferred the pressure to inter-well valves, we also applied a latched ternary multiplexer and reduced nine interconnection ports of inter-well valves to five. By diluting the sample with different dilution ratios based on the well array, the present chip can be easier for users and more suitable to high-throughput screen systems. (C) 2010 Elsevier B.V. All rights reserved.