Advisor:  Peter Hesketh, PhD (Georgia Institute of Technology, Mechanical Engineering)

Committee:        

         Alexander Alexeev , PhD (Georgia Institute of Technology, Mechanical Engineering)

         J. Brandon Dixon, PhD (Georgia Institute of Technology, Mechanical Engineering)

         Hang Lu, PhD (Georgia Institute of Technology, Chemical and Biomolecular Engineering)

         Todd Sulchek, PhD (Georgia Institute of Technology, Mechanical Engineering)

Mixing and Sampling in a Microfluidic Channel Using Rotating Magnetic Microbeads

This work presents a novel microsystem utilizing an array of rotating magnetic beads inside a microfluidic channel. The magnetic beads are actuated via a rotating magnetic field. The work demonstrates the fabrication of this device using non-standard MEMS fabrication materials.

The physical operational limits of the device are demonstrated and quantified. The effectiveness of this system is experimentally evaluated in two separate common microfluidic operations. The first operation is the ability for these beads to mix fluids inside a microfluidic channel. This is done by measuring the mixing of two streams of fluid as they flow over the rotating array of beads. The interaction between the speed of the bulk fluid and the speed of the rotating magnetic beads is studied as well as the effect of the path of the bead. The second operation is the capacity to capture particles from the microfluidic channel. This capturing is accomplished via protein-protein bond between the surface functionalizations of the magnetic bead and the particle. In capture experiments, the interplay between density of beads per channel length, channel height and bead rotational speed are studied.