A Liquid-Metal Based Spiral Magnetohydrodynamic Micropump.

Xuyan Zhou,Lin Gui,Meng Gao

doi:10.3390/mi8120365

Abstract

A liquid-metal based spiral magnetohydrodynamic (MHD) micropump is proposed in this work. The micropump was fabricated in a polydimethylsiloxane (PDMS)-glass hybrid microfluidic chip. This pump utilized two parallel liquid-metal-filled channels as electrodes to generate a parallel electrical field across the pumping channel between the two electrodes. To prevent contact and cross contamination between the liquid metal in the electrode channel and the sample fluid in the pumping channel, a PDMS gap was designed between the liquid metal and the sample fluid. To minimize the chip size, the parallel electrode and pumping channels were designed in a spiral shape. To test pumping performance, NaCl aqueous solution containing fluorescent particles (0.5 μm in diameter) was filled into the pumping channel as the working sample fluid. When a pair of identical magnets (0.4 T) was placed onto both top and bottom surfaces of the chip, the pump was able to drive the sample fluid at a flow velocity of 233.26 μm/s at 3000 V. The pump has no moving parts, and the electrodes are easily fabricated, making the pump suitable for miniaturization and integration into microfluidic systems.

Highlights

Lab-on-a-chip (LOC) is a technology that integrates biological and chemical applications, such as sample preparation, collection, reaction, separation, detection, and so on, into just one small chip [1]
As the “heart” of the whole microfluidic system, a micropump is widely used to drive the fluids in these microfluidic channels
Electroosmotic micropumps and electromagnetic hydrodynamic micropumps possess the merits of both non-mechanical micropumps and electric control methods

Summary

Introduction

Lab-on-a-chip (LOC) is a technology that integrates biological and chemical applications, such as sample preparation, collection, reaction, separation, detection, and so on, into just one small chip [1]. Mechanical micropumps have moving parts inside, such as pneumatic membranes [5,6,7], piezoelectric elements, acoustic components [8], electrostatic coils [9], electrochemical bubbles [10], shape memory alloy, and ultrasonic excitation [11]. These moving parts decrease the life span and operational stability of the pump. Electroosmotic micropumps are very convenient for microfluidic use, they are not suitable for driving conductive sample fluids such as electrolytic aqueous solutions, which are widely used in microfluidics. It has been widely used to drive conductive sample fluids in many microfluidic applications, including mixing [17], liquid chromatographs [18], and integrated fluidic networks [19]

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Conclusion