SUBJECT: Ph.D. Proposal Presentation
BY: Zhengchun Peng
TIME: Monday, May 11, 2009, 12:00 p.m.
PLACE: Love Building, 210
TITLE: On-Chip Manipulations of Magnetic Particles and Their Biomedical Applications
COMMITTEE: Dr. Peter Hesketh, Chair (ME)
Dr. Levent Degertekin (ME)
Dr. Minami Yoda (ME)
Dr. Mark Allen (ECE)
Dr. Hang Lu (ChBE)
Dr. William Heineman (Chem (Univ. Cincinnati))


A common approach used to facilitate the handling and analysis of biological components employs biocompatible micro/nano particles as the solid carrier of biomolecules. Due to the increasing demand for faster and cheaper analysis, microfluidic devices have been widely used to handle small-volume samples. The motivation of this research is to integrate the micro/nano particle-based manipulation inside microfluidic devices for high throughput biomedical analyses. In particular, this thesis focuses on developing dielectrophoresis- and magnetophoresis-based MEMS for biocompatible particle manipulation and exploring their applications in quantitative protein assays. For magnetic manipulation, we propose to construct the device with arrays of soft magnetic features inside an externally imposed magnetic field. The device will be used to trap and concentrate biologically modified magnetic particles from a flow of dilute particle suspension. Electrochemical sensing elements will be integrated in the device to quantify the proteins attached to the particle surface in-situ. For dielectrophoretic manipulation, we propose to use interdigitated electrodes inside a microfluidic channel and apply AC signals to them at different frequencies. At some frequency range, the electrodes will trap and concentrate the polymer particles from the flow. When switched to a different frequency range, they will levitate the particles. The temporal control of particle trapping and levitation with adjustable forces can be used to study the binding strength and the kinetics of protein interactions between those attached to the particle and those immobilized on the bottom surface of the channel. For magnetophoretic manipulation, we propose to design and fabricate multiple sets of parallel current-carrying wires and apply phase shifted DC signals to them to oscillate and transport the particles inside the microchannel. The application of this novel manipulation will be discussed.