An Experimental Design Method Leading to Chemical Turing Patterns

Adding a Turing Pattern Reaction Two chemical-reaction systems can form sustained stationary patterns (Turing patterns) in solution as the result of the movement of a diffusible species and the formation of negative feedback loops—the chlorite-iodide–malonic acid reaction and the ferrocyanide-iodate-sulfite reaction. Horváth et al. (p. 772 ) set out to find other examples based on three criteria—that the reaction can develop spatial bistability, that independent control of the negative feedback reaction can be achieved, and the activating and inhibiting processes can be decoupled by slowing down the diffusing species with a complexing agent. The thiourea-iodate-sulfite (TuIS) reaction could be developed into a system that produced different stationary patterns, including stripes and hexagonal arrays of spots. Thus, such Turing pattern–generating reactions are not necessarily uncommon.