The insertion of peptides and proteins into cell membranes is crucial for the functioning of cells, and also for the functioning of a variety of antibacterial reagents. Cells are continually subject to oxidation events. In this experiment we will use neutron reflection to investigate how oxidative damage changes the interaction between two different, well studied peptides, melittin and protegrin, and cell membrane models of differing composition. The results will help us understand better the factors that influence the interaction of different peptides with cell membranes, and how that interaction is changed by oxidative damage.