Tuning the Chemical Communication of Oscillating Microdroplets by Means of Membrane Composition

Synchronization of dynamic elements via chemical communication is a widespread phenomenon in nature and, hence, in many scientific fields, such as in biology, physics and chemistry, where systems capable of giving and receiving information are commonly found. In these systems, coupling and synchronization between elements is achieved by messenger molecules diffusing from one element to others that trigger and spread a chemical reaction. In nature, an important example of chemical communication and synchronicity can be found in cell populations, where the plasma membrane governs the trafficking of ions or molecules (among other mechanisms) into and out of the cells, thus dictating their collective dynamic. Herein, in a biomimetic approach, we used a microfluidic system to confine a "chemical information generator", consisting of the far-from-equilibrium Belousov-Zhabotinsky (BZ) reaction, in the aqueous core of monodisperse simple emulsion microdroplets. These microdroplets were surrounded by an oil phase containing the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine, doped with other amphiphilic molecules. Stabilized by the lipids layer contained in the oil phase, the drops could be brought in closest contact to be arranged in a 1D array, using a microfluidic device. The as-formed lipid membrane, at the contact surface, provided a diffusion path between the drops for the chemical species governing the dynamical behavior of the BZ oscillating reaction. We showed that the coupling mediated by the membranes had mostly an inhibitory character and that the communication could be controlled by the insertion of sodium tetradecyl sulfate and cholesterol as membrane dopants. Numerical simulations suggested that the hydrophobic properties and the lipid packing at the interface were of paramount importance for the transmembrane crossing of the pertinent chemical species.