Levich Institute Seminar Announcement, 09/26/2006

Tuesday, 09/26/2006
2:00 PM
Steinman Hall, Room #312
(Chemical Engineering Conference Room)

Professor Abraham Stroock
Cornell University
School of Chemical and Biomolecular Engineering


"Microfluidic Control of Mass Transfer for Micro-Fuel Cells and Tissue Engineering "

ABSTRACT


The advancement of microfluidic technology calls for the application of chemical engineering principles, the development of new experimental methods, and the definition of new target applications. I will discuss two efforts in my research group in which we have attempted to address this multiplicity of challenges. In a first theme, we have focused on a fundamental question regarding the role of three-dimensional laminar flows in controlling the rate of mass transfer to solid reactive boundaries in ducts. This question is relevant to the design of efficient microreactors that involve heterogeneous catalysts, and sensing technologies that involve binding at surfaces, as in protein- and DNA-chips. I will present results from simulation and theory that clarify the importance of chaotic advection in defining the rate of interfacial mass transfer from liquids. In particular, I will explain how the appropriate choice of a chaotic flow guarantees transition after a short entrance length into an asymptotic regime characterized by high, Peclet number-dependent values of the Sherwood number. I will conclude on this theme by presenting our experimental application of these concepts to the optimization of power density and fuel efficiency in a micro-fuel cell.

In a second theme, we have developed microfluidics as a mimic of the vascular system for the control mass transfer within biological materials for applications such as wound healing and tissue engineering. Using in vitro growth of cartilage as an example, I will discuss engineering principles for the design of microfluidic systems that provide spatial and temporal control of the chemical environment of cells (primary chondrocytes or cartilage cells) within three-dimensional scaffolds. I will then present experimental methods we have developed to embed functional microfluidic structure directly within cell-seeded hydrogels, and quantitative characterization of the mass transfer provided by these structures. I will demonstrate the use of these microfluidic scaffolds for the culture of thick sections of tissue and for the induction of spatially varying cellular behavior within single, monolithic scaffolds. I will conclude on this theme with discussion of the opportunities and challenges for the application of microfluidics to biomedical applications.

BRIEF ACADEMIC/EMPLOYMENT BACKGROUND:
  • B.A., Cornell University, Physics, 1995
  • M.S., University Paris VI and XI, Solid State Physics, 1997
  • Ph.D., Harvard University, Chemical Physics, 2002
  • Assistant Professor, School of Chemical and Biomolecular Engineering, Cornell University, 2003-
CURRENT RESEARCH INTERESTS:

In our research effort, we couple deterministic micro and nano-scale structure with physical principles to create new phenomena and technologies. As an integral part of this effort, we build conceptual foundations for these developments in order to direct our experimentation and establish engineering principles for future applications. With this spirit, we are pursuing three themes of research that allow us to address both timely technological challenges in microchemical technology, medicine, and materials development, and timeless questions in transport phenomena, biology, and chemical thermodynamics. Click here for website.