High constriction ratio continuous insulator based dielectrophoretic particle sorting

Low frequency insulator based dielectrophoresis (iDEP) is a promising technique to study cell surface dielectric properties. To date, iDEP has been exploited to distinguish, characterize, and manipulate particles and bacteria based on their size and general cell phenotype (e.g. gram positive vs. gram negative). However, separation of bacteria with diverse surface phenotypes but similar sizes sets a much higher demand on separation sensitivity, necessitating improvement in channel structure design in order to increase the electrical field gradient. In this work, a three dimensional insulator based dielectrophoresis (3DiDEP) microdevice is designed to achieve continuous particle sorting based on their size and, more importantly, on their surface dielectric properties. A 3D constriction is fabricated inside Poly (methyl methacrylate) (PMMA) channels using a micromilling technique. By controlling the channel geometry at the 3D constriction area, a nonuniform electric field with a large intensity gradient perpendicular to the local particle flow direction results in transverse particle deflection, driving particles into different outlet streams. With both simulation and experiments, we show that a diverse array of particles can be distinguished by 3DiDEP. This 3DiDEP sorter can be used in multiple applications in which the surface properties of cells or particles are of special interest.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2014

Author dc:creator

• Wang, Qianru, Ph. D. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Cullen R. Buie.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/93818

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/93818