We have recently improved the stability and coverage of free standing bilayers by the use of a supporting thiolipid layer on gold. The system has been investigated on POLREF and supports the use of magnetic contrast reflectometry. One use for this system is to contribute to our longer term plans to make models of bacterial outer membranes in which a periplasm separates the outer and inner membranes. In this proposal we intend to recreate the asymmetric bacterial outer membrane which has phospholipid on the inside and lipopolysaccharide on the outer. We will model the structures of up to three LPS molecules, examine the stability of the asymmetry and look at the binding of LPS dependent toxins