Rybak-Akimova Research Group

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Tufts U.

Spontaneous pattern formation in reaction-diffusion systems containing dioxygen:

Spatial self-organization (chemical waves and patterns) has been observed in oscillating chemical reactions. While the origins and mechanisms of these phenomena are of fundamental importance for the life sciences, the previously used reagents are incompatible with life. We found pattern formation in oxidations of substrates with air oxygen. This phenomenon seems to be fairly common, particularly in non-linear catalytic oxidation. We are intrigued by the scope and mechanism of this spatial self-organization relevant to dioxygen activation reactions studied in our lab. We have already found two simple inorganic systems capable of pattern formation: Co(II) - N₃^- - SO₃^2- - O₂, and Co(II) - ethylenediamine - O₂. Systematic studies of these systems reveal significant role of convection in pattern formation in liquid solutions, and reaction-diffusion (Turing) patterns observed in gels (manuscript in preparation). More recently, spatial self-organization was found in an enzyme-catalyzed oscillating reaction (NADH - O₂ - peroxidase - methylene blue). This system is light-sensitive, which opens new possibilities of regulating the patterns. Detailed understanding of reaction dynamics in pattern forming chemical systems will help in interpretation of the results.