Micro-fluidic Technologies for Blood Diagnostics

We report several micro-fluidic technologies developed at our Center for Microfluidics and Medical Diagnostics to load, separate, concentrate, probe and analyze blood samples in miniature medical diagnostic kits. Such technologies have potential applications for glucose, coagulation, ovulation, drug and even bacteria/viral detection in blood samples. Blood is a complex fluid because blood cells can migrate, sediment and coagulate under flow and thus rendering the blood rheology memory dependent, visco-elastic and shearthinning.

The resulting complex blood hydrodynamics have made it difficult to design miniature blood diagnostic kits. We have exploited the hydrodynamic vortices of AC electro-osmotic flow (EOF), the electrophoretic and dielectrophoretic (DEP) mobilities of the blood cells, the deformability and negative buoyancy of the blood particles and the electrostatic interaction between blood cells and micro-electrodes to produce an array of techniques to handle blood suspensions in micro-fluidic devices. The specific devices we will present include a micro-needle for blood loading that alleviates the meniscus packing phenomenon, a T-element AC EOF pump for blood suspension without moving parts, an individual bioparticle Impedance probe using electrode arrays, a micro-mixer to prevent blood cell coagulation and aggregation, a blood cell/bacteria focusing kit using DEP and a blood cell-plasma separation device based on buoyancy.

Brief Bio

Hsueh-Chia Chang received his BS from Caltech and PhD from Princeton, both in Chemical Engineering. He has taught at UC Santa Barbara, University of Houston and University of Notre Dame, where he has been since 1987. He was the department chair from 1989 to 1995 and is currently the Director of the Center for Microfluidics and Medical Diagnostics. He also holds the Bayer Chair of Engineering at the University of Notre Dame.

Professor Chang is known for his research in interfacial dynamics and Micro-fluidics. He is the leading authority on falling-film wave dynamics and is the author of the definitive book "Complex Wave Dynamics on Thin Films" (Elsevier Science, 2002) on the subject. He and his co-workers have deciphered the various dynamic transitions of this important multi-phase instability. He has championed the use of non-equilibrium AC and DC electro-kinetics in micro-fluidic devices. He is developing new technologies based on these mechanisms at his Center.

Professor Chang won the Frenkiel award from the American Physical Society and was elected a fellow of that society for his contributions to interfacial dynamics. He has delivered several named lectures and keynote speeches on his micro-fluidic work, including the Colburn Lecture at the University of Delaware, the Corrsin lecture at Johns Hopkins and a keynote address at the 1998 International Congress of Chemical and Process Engineering, the largest Chemical Engineering meeting of the world .