Interaction of the Belousov-Zhabotinsky reaction with phospholipid engineered membranes

Compartmentalized in liposome arrays, the Belousov-Zhabotinsky (BZ) oscillatory reaction might represent a good model for biochemical networks. In order to engineer such liposomes, we used small-angle X-ray scattering (SAXS) to study the effect of individual BZ reactant as well as of the entire BZ mixture on the structural properties of lipid layer(s) formed by 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) phospholipids in aqueous media. These properties were compared with those of lipid layers doped with myristic acid (Myr-A), sodium tetradecyl sulfate (STS), and cholesterol (CHOL). In parallel, the effect on the BZ reaction exerted by doped DMPC liposomes was investigated by UV-vis spectroscopy, followed by image analysis of the recorded time series. SAXS experiments showed that chemical species involved in the BZ reaction bring small changes to the internal structure of DMPC bilayers. However, ferroin can reduce the liposome lamellarity by being adsorbed on the surface of lipid layers. Also, the presence of charged dopants such as STS and TA tends to reduce the lamellarity of liposomes, while CHOL brings marked changes in the BZ system due to chemical reaction with oxidant species. In particular, an increase of the oscillation frequency is observed when the BZ reaction is carried out in the presence of CHOL-DMPC liposomes. For this behavior, a possible explanation supported by numerical simulations is bromination of CHOL double bonds by BZ intermediates.