Goddard Space Flight Center, Greenbelt, Maryland 20771

ENGINEERING COLLOQUIUM

Monday, December 8, 2003 / 3:30 PM, Building 3 Auditorium

Ron Weiss

"Engineering Living Cells with Computation"

ABSTRACT -- Biological organisms sense their environment, process information, and continuously react to both internal and external stimuli. We can now harness organisms as computational substrates, and extend their behavior by embedding biochemical logic circuitry that controls intra- and inter-cellular processes. The engineering and construction of reliable in-vivo logic circuitry enables a wide range of programmed applications. The application areas include programmed therapeutics and tissue engineering, drug manufacturing, embedded intelligence in materials, biological sentinels that can sense and effect environmental conditions, gene therapy, and biomaterial fabrication. In this talk, I will describe research that uses computer engineering principles of abstraction, composition, and interface specifications to build programmable bio-organisms with sensors and actuators precisely controlled by analog and digital logic circuitry. Here, recombinant DNA-binding proteins represent signals, and recombinant genes perform the computation by regulating protein expression. I will describe synthetic gene networks that implement biochemical logic circuits in Escherichia coli fabricated using the AND, NOT, and IMPLIES logic gates. I will discuss using both rational design and directed evolution for the construction of complex but reliable biochemical logic circuits. We are using these methods to build a variety of synthetic gene networks, including circuits that perform signal processing to detect specific chemical gradients and generate pulses. We are constructing genetic circuits that instruct cells to perform simultaneous multi-way communications using multiple quorum sensing systems, that together with the signal processing, analog, and digital circuits will allow us to coordinate and control the behavior of cell aggregates.

SPEAKER -- Ron Weiss is an Assistant Professor of Electrical Engineering at Princeton University, and is also associated with the Department of Molecular Biology. He received his PhD from the Massachusetts Institute of Technology in Computer Science and Electrical Engineering (2001). His research focuses on modeling and constructing biochemical and cellular computing systems for the purpose of programming cells. A major thrust of his work is the synthesis of gene networks that are engineered to perform in vivo analog and digital logic computation. He is also interested in programming cell aggregates to perform coordinated tasks using cell-cell communication with chemical diffusion mechanisms such as quorum sensing. He has constructed and tested several novel in-vivo biochemical logic circuits and intercellular communication systems. Weiss is interested in both hands-on experimental work and in implementing software infrastructures for simulation and design work. He has received MIT's Technology Review Magazine's TR100 Award ("top 100 young innovators", 2003), was selected as a speaker for the National Academy of Engineering's Frontiers of Engineering Symposium (2003), and received the E. Lawrence Keyes, Jr./Emerson Electric Company Faculty Advancement Award at Princeton University (2003).