On logical universality of Belousov-Zhabotinsky vesicles

Belousov-Zhabotinsky (BZ) excitable chemical medium exhibits a rich variety of spatial patterns of excitation. In a sub-excitable light-sensitive chemical medium, an asymmetric disturbing or excitation, causes formation of localized travelling excitation wave-fragments. When two or more wave-fragments collide, they annihilate or merge into new wave-fragment. The wave-fragments can be thought as elementary units of information and their interaction sites as a logical gates. Size and life span of a wave-fragment depends on a level of medium’s illumination. By encapsulating BZ reaction into a lipid vesicle, we can manipulate the BZ-derived logical gates. By interpreting wave-fragments as values of Boolean variables, we design a collision-based polymorphic logical gate in BZ vesicles. The gate implements operation XNOR for low illumination, and it acts as nor gate for high illumination