CAREER: Programming Chemical Reactions in Space and Time: Micro and Nanoscience via Reaction-Diffusion in Complex Microgeometries

Northwestern University, Evanston IL

Investigators

Abstract

Project Summary: CAREER: Programming Micro and Nano Fabrication and Manufacturing in Complex Micro-geometries with Reaction-Diffusion Processes (CTS-0547533 / Northwestern U. / Bartosz Gryzbowski ) Intellectual Merit. The investigator (PI) plans to develop a unique class of chemical systems, in which reaction-diffusion (RD) processes can be programmed in space and time to perform complex tasks in micro and nanofabrication. In two dimensions, these systems will be based on the Wet Stamping (WETS) method the PI developed, and will use hydrogel stamp micro-patterned in bas relief to initiate chemical reactions in other media. By combining WETS with pressure driven and/or electro-osmotic flows, the PI will be able to direct different reagents to different initial locations, and to start multiple RD processes in parallel. This programmable RD (p-RD) approach will allow preparation of unique micro and nano-architectures both in soft (gels, polymers) as well as hard (glasses, crystals) materials. It will lead to immediate applications in materials science, micro-fluidics, cell biology and catalysis. Extension of p-RD to three dimensions will provide foundation for a bio-inspired self-assembly methodology, in which intelligent components communicate and recognize one another by exchanging chemicals they carry. In addition, strategies of remote fabrication or manufacturing inside of small objects will be developed, and will provide the basis for preparing open-lattice colloidal crystals and catalytic micro-reactors. Experimental work on both 2D and 3D p-RD systems will be accompanied by a theoretical effort to understand, control and direct reaction-diffusion processes occurring at small scales and initiated from arbitrary geometries. The CAREER project will reintroduce the classical concepts of transport processes into the rapidly growing fields of micro and nano-science. The ability to program sequences of chemical reactions to make small structures and systems is a conceptually new approach, different from the standard micro/nano-fabrication and manufacturing schemes. The junction of ideas from various disciplines will help reinforce the image of chemical engineering as a place that unifies concepts from more specialized fields, and uses these concepts in useful ways. Broader Impacts: Science, Technology and Society. Devices and flexible manufacturing schemes based on p-RD developed under this Proposal will be useful both in basic research and in industry. Immediate practical applications of 3D micro-fluidic devices and micro-optical components are envisioned. Supports for studying cell motility will provide a test-bed for rapid verification of hypotheses related to cancer research, and the protein-ligand binding assays have the potential to become a general tool for screening biological interactions. Gradient-based methods for screening crystallization conditions and catalytic activity will eliminate the need of serial experiments and robotic equipment. By virtue of their small scale, these methods will minimize the amounts of chemicals used and disposed, and will be not only economical but also environmentally friendly. Broader Impacts: Education. The phenomena and systems studied under this project will have a broad educational impact, both within and outside the PIs research group. Students directly involved in this work will be exposed to a range of experimental and theoretical techniques at the junction of several disciplines (engineering, chemistry, physics, mathematics), and will learn how to conduct interdisciplinary research. Collaborative effort, mentoring of undergraduate and high-school students and sharing of the groups research activities with others will be emphasized. The PIs educational philosophy based on the pillars of creativity, interdisciplinarity and enthusiasm has been and will be an integral part of the core courses he teaches (via open-ended research projects) as well as special educational activities he initiated (Undergraduate Math Olympiad and Entrepreneurship Lecture Series). Visual images of scientific results will be used broadly to popularize modern science and engineering among young people, and will help overcome a stereotype that engineering/physical sciences cannot be aesthetic. An art exhibit featuring graphical representations of RD processes will be organized in collaboration with a professional artist as well as high-school and undergraduate students involved in the groups research. Ongoing collaboration with Northwestern University learning center will lead to the development of classroom demonstrations of reaction-diffusion systems and nonlinear processes. Popular science talks in local high-schools (several of them with high proportion of minority students) are intended. The results of the proposed work will be disseminated widely through exhibits, professional and popular science journals, conference talks, presentations, and the PIs group website (dysa.northwestern.edu) as part of a continuing education program for the public at Northwestern.