Macroscopic Dynamics as Reporter of Mesoscopic Organization: The Belousov-Zhabotinsky Reaction in Aqueous Layers of DPPC Lamellar Phases

The propagation of traveling chemical waves in the excitable BelousovZhabotinsky (BZ) system when performed in the presence
of 1,2-dipalmitoyl-sn-glycero-3-phosphatidyl choline (DPPC) bilayers responds sensitively to the phospholipid content. The
characteristic features of wave propagation, such as spiral pitch, rotation period, and size of the spiral core region, show two regions
of different behavior, one below and the other above a DPPC content of 12.5% (w/w) thus suggesting a transition in the
organization of the lipid domains at a DPPC content of ∼12.5% (w/w). This transition is supported by small-angle X-ray scattering
data, which show pronounced changes in the coherence lengths of the lyotropic smectic domains. Thus, the dynamics of the
chemical system occurring at a macroscopic length scale reflects the organization of the water/lipid domains which extend over
mesoscopic lengths. These findings indicate that in the BZ/DPPC system, there is an interaction between processes that occurs at
length scales differing by as much as 3 orders of magnitude