PhD Defense, Chris Earhart (July 28, Wednesday, 2010, CISX Auditorium 9:30 am)

A Ph.D. Defense Announcement

"Magnetic Sifter and Nanoparticles for Cell and Protein Separation"

PhD Candidate: Chris Earhart

Department of Materials Science and Engineering

Advisor: Professor Shan X. Wang

Date: Wednesday, July 28, 2010
Time: 9:30 am (refreshments at 9:15 am)
Place: CIS-X Auditorium (Rm 101)

Abstract:

Nanoscience and nanotechnology have been applied in recent years to cancer research, with the goal of making a revolutionary change in the ways in which cancer is diagnosed and treated.  Magnetic nanotechnologies, in particular, have shown significant potential in several areas such as imaging, therapeutics, and early detection.  The topic of this presentation is a novel magnetic separation device, the magnetic sifter, and physically fabricated magnetic nanoparticles for applications in cell and protein separation. 

The magnetic sifter is a microfabricated planar die containing a dense array of pores (~200-5000/mm²) in a magnetically soft membrane.  When magnetized by an external field, the sifter pores generate large magnetic field gradients near the pore edges, which capture nanoscale magnetic carriers during flow with high efficiency and throughput.  The magnetic sifter is a microfluidic device, in the sense that it contains microfabricated, micron-scale pores for fluid flow.  It is also a macrofluidic device, in that high-volume throughput is achieved by parallel flow through the large number of pores. 

When paired with magnetic carriers functionalized with recognition moieties, the magnetic sifter can be used in both cell and protein enrichment schemes.  Separations of magnetically labeled tumor cells and individual magnetic nanoparticles using the sifter will be discussed.  With its planar structure and presentation of captured cells, the sifter can also be used as a cell imaging platform.  The use of the sifter to capture and quantify low concentrations (~100/mL) of tumor cells in whole blood samples has been demonstrated.

Lastly, a method for high-throughput fabrication of novel magnetic carriers, synthetic antiferromagnetic (SAF) nanoparticles, will be presented.  The method has enabled production of large quantities of SAF nanoparticles, which have desirable properties for applications in magnetic separation.  The capture and release of SAF nanoparticles with the magnetic sifter has been shown.  High capture efficiencies are achieved at flow rates 10-20x higher than what was previously possible with commercially available magnetic carriers.