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Issue 9, 2007
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A virtual valve for smooth contamination-free flow switching

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We present a channel geometry that allows for clean switching between different inlets of a microchip without any contamination of the inlets or the downstream flow. We drive this virtual valve with a pneumatic pressure setup that minimizes disturbance of the downstream flow during the switching procedure by simultaneous variation of the pressures applied to the different inlets. We assess the efficiency of the setup by spectroscopic measurement of downstream dye concentrations, and demonstrate its practical utility by sequentially constructing multiple layers of alginate hydrogel. The method is potentially useful for a whole series of further applications, such as changing perfusion liquids for cell culture and cell analysis, metering, chemical-reaction initiation and multi-sample chromatography, to name a few.

Graphical abstract: A virtual valve for smooth contamination-free flow switching

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Article information

04 Jun 2007
12 Jul 2007
First published
20 Jul 2007

Lab Chip, 2007,7, 1111-1113
Article type

A virtual valve for smooth contamination-free flow switching

T. Braschler, J. Theytaz, R. Zvitov-Marabi, H. V. Lintel, G. Loche, A. Kunze, N. Demierre, R. Tornay, M. Schlund and P. Renaud, Lab Chip, 2007, 7, 1111
DOI: 10.1039/B708360B

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