Personal Information and Interests

Education:
M.S. Chemical Engineering Practice
Massachusetts Institute of Technology, 1999

B.S. Chemical Engineering
University of Maryland at College Park, 1997

Academic Interests

Research Interests: Magnetophoretic Cell Clarification
Thesis Advisor: Alan Hatton

Research Description

The focus of this research is on a new technique for removing cells from fermentation broth. The new technology takes advantage of the force that a non-magnetic particle feels when immersed in a magnetic fluid that is subjected to a magnetic field gradient. The non-magnetic particle is forced by the magnetization of the surrounding magnetic fluid away from areas of high magnetic field strength and into areas of low magnetic field strength. In this way, non-magnetic particles, in our case E.coli cells, can be focused and moved out of the bulk fluid by applying a magnetic field gradient to the system, leading to magnetophoretic cell clarification.

The magnetic fluid itself is composed of magnetite nanoparticles coated with a polymer layer that stabilizes the nanoparticles in water and prevents their aggregation. The magnetic nanoparticles are approximately 30 nm in diameter, with the magnetite core itself being approximately 8-10 nm in diameter, and the small size of these particles allows the magnetic fluid itself to be treated as a continuum in comparison to the size of the cells being separated.

Experiments were performed using both a counter current device and a quadrupole device. For the counter current device, feed fluid is introduced through a tube at a controlled flow rate, while a series of magnets placed around the tube move counter to the direction of the feed flow. The traveling magnetic field created by the moving magnets exerts a force on the cells in the feed mixture that pushes them in the same direction as the magnets. Thus, the cells are captured, transported, and removed from the feed by the movement of the magnets. Up to 95% of cells can be removed from a feed mixture after one pass through the counter current device. The quadrupole device is a newer design, with a set of four stationary magnets surrounding a central column. The placement of the magnets results in areas of high magnetic field at the column walls and areas of low field in the center of the column. Cells are therefore focused into the middle of the column as the feed flows through it, and can then be separated from the remaining bulk fluid at the outlet end of the column. Preliminary tests show that the quadrupole device is successful in collecting and removing cells from the bulk fluid, and experiments are ongoing to examine the full potential of this new separation technology.