title: A high current density DC magnetohydrodynamic (MHD) micropump.
abstract: This paper describes the working principle of a DC magnetohydrodynamic (MHD) micropump that can be operated at high DC current densities (J) in 75-microm-deep microfluidic channels without introducing gas bubbles into the pumping channel. The main design feature for current generation is a micromachined frit-like structure that connects the pumping channel to side reservoirs, where platinum electrodes are located. Current densities up to 4000 A m(-2) could be obtained without noticeable Joule heating in the system. The pump performance was studied as a function of current density and magnetic field intensity, as well as buffer ionic strength and pH. Bead velocities of up to 1 mm s(-1) (0.5 microL min(-1)) were observed in buffered solutions using a 0.4 T NdFeB permanent magnet, at an applied current density of 4000 A m(-2). This pump is intended for transport of electrolyte solutions having a relatively high ionic strength (0.5-1 M) in a DC magnetic field environment. The application of this pump for the study of biological samples in a miniaturized total analysis system (microTAS) with integrated NMR detection is foreseen. In the 7 T NMR environment, a minimum 16-fold increase in volumetric flow rate for a given applied current density is expected.
authors.affiliation: Institute of Microtechnology, University of Neuchatel, Switzerland. Alexandra.Homsy@unine.ch
authors.forename: Alexandra
authors.initials: A
authors.lastname: Homsy
authors.forename: Sander
authors.initials: S
authors.lastname: Koster
authors.forename: Jan C T
authors.initials: JC
authors.lastname: Eijkel
authors.forename: Albert
authors.initials: A
authors.lastname: van den Berg
authors.forename: F
authors.initials: F
authors.lastname: Lucklum
authors.forename: E
authors.initials: E
authors.lastname: Verpoorte
authors.forename: Nico F
authors.initials: NF
authors.lastname: de Rooij
mesh_terms: D004563:Electrochemistry; D004566:Electrodes; D004574:Electromagnetic Fields; D004867:Equipment Design; D006863:Hydrogen-Ion Concentration; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods; D008962:Models, Theoretical; D009994:Osmolar Concentration; D012680:Sensitivity and Specificity