A Handy Liquid Metal Based Non-Invasive Electrophoretic Particle Microtrap.

Lu Tian,Meng Gao,Lunjia Zhang,Lin Gui,Zhong-Shan Deng

doi:10.3390/mi9050221

Abstract

A handy liquid metal based non-invasive particle microtrap was proposed and demonstrated in this work. This kind of microtrap can be easily designed and fabricated at any location of a microfluidic chip to perform precise particle trapping and releasing without disturbing the microchannel itself. The microsystem demonstrated in this work utilized silicon oil as the continuous phase and fluorescent particles (PE-Cy5, SPHEROTM Fluorescent Particles, BioLegend, San Diego, CA, USA, 10.5 μm) as the target particles. To perform the particle trapping, the micro system utilized liquid-metal-filled microchannels as noncontact electrodes to generate different patterns of electric field inside the fluid channel. According to the experimental results, the target particle can be selectively trapped and released by switching the electric field patterns. For a better understanding the control mechanism, a numerical simulation of the electric field was performed to explain the trapping mechanism. In order to verify the model, additional experiments were performed and are discussed.

Highlights

Manipulation of a single particle, droplet, or cell is a critical tool for microfluidic analysis in many applications including flow cytometer detection, biochemical analysis, and so on [1,2,3]
Where εr dynamic is the dielectric constant of viscosity of silicon oil; and ζ sisilizceotμnaepo=oilt;eε2n0εt3iirasεηl0.thζTehepezremtaitptoivteitnytioafl free space (C2·N−1·m−2); η is of these particles in silicone oil was positive (6.8 mV, measured by a particle analyzer, DelasTM Nano C, Beckman Coulter, Brea, where εr is the dielectric constant of silicon oil; ε0 is the permittivity of free space (C2·N−1·m−2); η is dynamic viscosity of silicon oil; and ζ is zeta potential
To explain the mechanism of the particle movement, numerical simulations of the electric field are presented by COMSOL Multiphysics 5.2a (Stockholm, Sweden) (Figure 4)

Summary

Introduction

Manipulation of a single particle, droplet, or cell is a critical tool for microfluidic analysis in many applications including flow cytometer detection, biochemical analysis, and so on [1,2,3]. As the methods of manipulating particles, droplets, and cells are sometimes similar, the development of any one of them will help the others. The methods of manipulating a single particle, droplet, and cell have been quickly developed. They can be divided into two categories: passive methods and active methods. Droplets are passively captured in a microchannel cavity through capillary valve action and released on-demand through a triggered surface acoustic wave pulse In their device, the droplets can be selected on-demand from an emulsion of continuously flowing droplets and the single droplet can be incubated for a desired duration of time. Haoswpervoepr,otsheids dfeovrictehceancanpottupricek, umpaansipinugllaetpioanrt,icalenfdrormelease of a singlIen pthairstwicoler.k,Tahmisicrdoefvluiicdeicudteilviziceedwlaisqupridop-moseetdaflofir ltlheedcacphtaunren,emlsanaispuellaetcitorno,daensd troelepaesrefoofrma the activesinmgalenpipaurtliacltei.oTnhoisf dtheveictearugteiltizpedarltiiqculeidu-msientagl efillelecdtrochpahnonreelssiass(eElePc)trfoodrecse.toTpheerffoarbmritchaetiaocntivoef this micromflaunidipiuc ldateivoinceoifs vtheerytsairmgept lep,acrhtiecalep,uasnindgcoenlevcetrnoipehnot,rewsihsic(hEPca) nfobreceh.elTphfue l ffaobrritchaetiionntegofratthioisn and miniamtuicrriozfalutiiodnicodfetvhiceeseismviecrryosdimevpilec,eschienatpo,laanrgdec-osncavleenimenict,rowflhuicihdiccansybsetehmelsp.ful for the integration and miniaturization of these micro devices into large-scale microfluidic systems

Liquid Metal Based Particle Microtrap

Electric Potential Particle Trap Design

Particle Capture and Release

Discussion