Irving R. Epstein
Irving Epstein
Henry F. Fischbach Professor of Chemistry and HHMI Professor
Ph.D., Harvard University
Research in our group covers oscillatory chemical reactions, spatial pattern formation, dynamical systems and neurobiology.
Many phenomena in living systems involve periodic changes. In the past decade, oscillating chemical reactions have blossomed from a curiosity studied by an obscure group of Russians to a major area of scientific research. We study these systems both experimentally and theoretically, from several points of view. We have achieved the first successful design of a new chemical oscillator. We have used our systematic design algorithm to expand the family of chemical oscillators from two accidentally discovered reactions to some two dozen deliberately constructed systems. While we continue the search for new types of oscillators, we probe by a variety of techniques, including spectrophotometry, potentiometry, rapid mixing and computer simulation, the mechanisms of those that have already been discovered.
Chemical oscillators can be "tweaked" to give a variety of related phenomena, some with suggestive connections to biological systems. We study spatial pattern formation, in which an initially homogeneous medium spontaneously gives rise to concentric rings, or spiral color patterns resembling those seen in embryonic development or the aggregation of slime molds, and chemical chaos, in which concentrations oscillate deterministically, but in an aperiodic and apparently irreproducible fashion that depends very sensitively on the initial conditions. We investigate, both experimentally and theoretically, Turing structures, patterns that arise from the interaction of reaction and diffusion, which have been suggested as the mechanism of spatial pattern formation in phenomena ranging from biological morphogenesis to geological stratification.
We are interested in the phenomena that can occur when two or more oscillators are coupled together, either physically, i.e., by diffusion or an electrical connection, or chemically, by having two oscillators share a common chemical species. Such systems can give rise to surprising phenomena, such as "oscillator death," the cessation of oscillation in two coupled oscillating systems, or the converse, "rhythmogenesis," in which coupling two systems at steady state causes them to start oscillating. Coupled chemical oscillators provide simple models for networks of oscillatory neurons. We have begun to apply some of the insights gained in our studies of coupled chemical oscillators to the modeling of small neural networks in conjunction with the Marder laboratory, to develop chemical analogs of neural oscillators and to coupling chemical and neural oscillators.
Recent Publications
See Dr. Epstein's Group web site for a complete list of publications.
High-Frequency Oscillations in the Belousov-Zhabotinsky Reaction. Ba´nsa´gi T, Leda M, Toiya M, Zhabotinsky AM, Epstein IR. J Phys Chem A. 2009 Apr 17.
Temperature control of pattern formation in the Ru(bpy)(3)(2+)-catalyzed BZ-AOT system. McIlwaine R, Vanag VK, Epstein IR. Phys Chem Chem Phys. 2009 Mar 14;11(10):1581-7. Epub 2009 Jan 19.
Cross-diffusion and pattern formation in reaction-diffusion systems. Vanag VK, Epstein IR. Phys Chem Chem Phys. 2009 Feb 14;11(6):897-912. Epub 2008 Dec 11.
Small-amplitude and mixed-mode pH oscillations in the bromate-sulfite-ferrocyanide-aluminum(III) system. Kovacs K, Leda M, Vanag VK, Epstein IR. J Phys Chem A. 2009 Jan 8;113(1):146-56.
Toiya M, Vanag VK, Epstein IR. "Diffusively coupled chemical oscillators in a microfluidic assembly." Angew Chem Int Ed Engl. 2008;47(40):7753-5.
V.K. Vanag and I.R. Epstein, “Patterns of Nanodroplets: The BZ-AOT Microemulsion System,” in Self-Organized Morphology in Nanostructured Materials, K. Al-Shamery and J. Parisi, eds., Springer, Berlin, 2008, pp. 89-113.
I. R. Epstein, I. B. Berenstein, M. Dolnik,V. K. Vanag, Lingfa Yang and A. M. Zhabotinsky, “Coupled and Forced Patterns in Reaction-Diffusion Systems,” Phil Trans. Roy. Soc. A 366, 397–408 (2008).
J. Carballido-Landeira, I. Berenstein, P. Taboada, V. Mosquera, V. K. Vanag, I. R. Epstein, V. Pérez-Villar and A. P. Muñuzuri,. “Long-lasting dashed waves in a reactive microemulsion,” Phys. Chem. Chem. Phys. 10, 1094–1096 (2008).