Contact Info
Department of Applied Mathematics
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 519-888-4567, ext. 32700
Fax: 519-746-4319
PDF files require Adobe Acrobat Reader
MC 6460
Dr. Henry Shum
Department of Chemical & Petroleum Engineering | University of Pittsburgh
Harnessing Chemical Reactions for Novel Functionality in Microfluidic Systems
Chemical reactions are essential for biological processes, from the directed transport of molecules within a cell to the carefully orchestrated growth and morphological development of an organism. As we expand our experimental capabilities in nanofabrication and synthetic biology, it is becoming possible to construct artificial microscale systems that incorporate biological components or function on the same principles as their living analogues. Here, we examine two potential applications of chemical reactions in synthetic systems, namely, to generate tunable fluid flow fields in an enclosed microfluidic device and to design "artificial cells" that communicate with each other. Recent experiments demonstrated that an immobilised patch of enzyme could function as a pump, generating persistent flows in a small, fluid-filled chamber. Experimental evidence suggested that the fluid motion was due to buoyancy effects. We develop a mathematical model to describe the changes in fluid density in the chamber due to a generic chemical reaction. Unexpectedly, we find that non-trivial, time-dependent fluid flows can be generated even under the assumption that the reaction rate is constant. This raises the intriguing possibility of a new paradigm for achieving complex flow and particle transport in microfluidic devices. A network of enzymatic pumps could autonomously and dynamically regulate flow to transport cargo "intelligently". Before we can design such systems, however, we must understand the more general and fundamental problem of chemical reaction networks in spatially extended systems. Building on studies of gene regulatory network dynamics based on ordinary differential equations, we model the behaviour of colonies of artificial cells that act as localised sources of chemicals. We show that imposing an oscillatory reaction network known as the repressilator to regulate chemical production in the cells endows them with the capability to collectively gauge the population size and density of the colony, a common ability in microorganisms referred to as quorum sensing. Thus, simple physical and chemical processes can be harnessed to attain life-like, biomimetic functionality in synthetic systems.
Contact Info
Department of Applied Mathematics
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 519-888-4567, ext. 32700
Fax: 519-746-4319
PDF files require Adobe Acrobat Reader
The University of Waterloo acknowledges that much of our work takes place on the traditional territory of the Neutral, Anishinaabeg and Haudenosaunee peoples. Our main campus is situated on the Haldimand Tract, the land granted to the Six Nations that includes six miles on each side of the Grand River. Our active work toward reconciliation takes place across our campuses through research, learning, teaching, and community building, and is co-ordinated within the Office of Indigenous Relations.