Controlling Coupled Chemical Oscillators: Toward Synchronization Engineering and Chemical Computation

The collective behaviors of coupled oscillators are ubiquitous in biological systems, with examples including quorum sensing, cardiac muscle contractions, and networks of neurons. In an effort to better understand the generic properties of such oscillators, we investigated emulsions of diffusively coupled microdroplets containing the oscillatory Belousov—Zhabotinsky (BZ) reaction with a photo-inhibitive catalyst. We created packed 2D arrays of BZ droplets via microfluidic techniques and studied the behavior of particular geometries with opticallyinduced boundary conditions. We used optical perturbations to alter periods and phases of oscillation in a controlled fashion, and also to completely suppress oscillations in the BZ droplets. Furthermore, we exploited the observed inhibitory coupling to establish a basis for computation through a chemical substrate by creating a functional NOR gate in a simple 1D arrangement of three BZ droplets.