title: A virtual valve for smooth contamination-free flow switching.
abstract: 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.
authors: EPFL, LMIS 4, Station 17, BM3125, Lausanne, VD 1015, Switzerland. thomas.braschler@epfl.ch
authors: Thomas
authors: T
authors: Braschler
authors: Joel
authors: J
authors: Theytaz
authors: Ronit
authors: R
authors: Zvitov-Marabi
authors: Harald
authors: H
authors: van Lintel
authors: Grazia
authors: G
authors: Loche
authors: Anja
authors: A
authors: Kunze
authors: Nicolas
authors: N
authors: Demierre
authors: Raphael
authors: R
authors: Tornay
authors: Mario
authors: M
authors: Schlund
authors: Philippe
authors: P
authors: Renaud