Development of dielectrophoresis chromatography employing asymmetric insulating structures and electric fields

Rochester Institute Of Tech, Rochester NY

Investigators

Abstract

A lab-on-a-chip is capable of automatically performing multiple complex chemical diagnostics in an electronic device that will easily fit on your thumb. As a lab-on-a chip manipulates an extremely small volume of fluid, it is also termed a microfluidic device. Miniaturization enables portability and accessibility, and opens the door for taking the chemical laboratory to where it is needed, be that a production line, a remote medical clinic, a sensitive environment, or real time monitoring of food and water safety. From a technical standpoint, miniaturization leads to higher resolution and sensitivity, improved integration, lower cost, and an extremely rapid processing time. To manipulate and sort biological particles, such as cells and complex macromolecules, dielectrophoresis is one of the most common techniques, as it relies on differences in particle response to an applied electric field. Living and dead cells respond differently to a nonuniform electric field than dead cells, as do cells from different organisms. Insulator-based dielectrophoresis adds another "knob" for particle sorting, with the placement of three-dimensional insulating structures as obstacles in the path of particle migration which "squeeze" the electric field. Theory predicts that using asymmetric obstacles provides yet another "knob" to sort particles. This project will experimentally validate the use of asymmetric insulating structures and nonuniform electric fields to sort and isolate biological particles in a microfluidic device. Asymmetric insulating dielectrophoresis will induce acceleration in some biological particles, and deceleration in others, with instantaneous velocity determined by particle geometry and charge. Differences in acceleration will lead to different residence times, creating a separation that is similar to a chromatographic process, creating the first demonstration of dielectrophoretic chromatography. A combination of carefully designed insulating post geometries with customized DC-biased, low frequency AC electric signals in insulator-based dielectrophoresis will be used to screen various bioparticles of interest, with variations in size, shape, and charge. The chromatographic effect will lead to distinct interaction with the stationary phase, and differential migration of the particles through the device. Particles will be eluted from the stationary phase as a ?peak? of concentrated particles and directed to a specific reservoir within the device for collection. This project will advance the state of the art in microfluidics by developing a new technique to sort and isolate particles. The present project will provide a premier research opportunity for undergraduate and graduate students, and will also assist in providing research opportunities for female students through the Women in Engineering programs.