ROLE OF THE BILAYER-BILAYER INTERACTION ON THE RIPPLE STRUCTURE OF SUPPORTED BILAYERS IN SOLUTION

We have developed a method to prepare supported double bilayers made o f phospholipids to facilitate in-solution studies of the bilayer-bilay er interaction of biologically relevant model membranes. It is found t hat a ripple structure, with an average wavelength of 27 nm, appears a t room temperature in the double-bilayer region only, Some large rippl es, of an average wavelength of 53 nm, are also observed on the double -bilayer region and are extremely soft and flexible. These experimenta l observations demonstrate that the bilayer-bilayer interaction may pl ay a role to induce the formation of the ripple structure in our syste m. We also found that the formation of the ripple structure takes a fe w minutes or less while cooling to room temperature,and the relaxation of the ripple structure takes over 10 h at room temperature or 4 degr ees C.