Antimicrobial resistance is a global epidemic and has occurred due to a widespread antibiotic overconsumption. Gram negative bacteria, such as P. aeruginosa (leading cause of mortality in cystic fibrosis patients) are of particular concern due to the limited permeability of bacterial cell wall to antibiotic drugs. One promising strategy is to increase the permeability of the bacterial outer membrane prior to antibiotic delivery. Annexin A5 is a calcium-dependent phospholipid binding protein that targets phosphatidylserine (PS) and under certain conditions can destabilize membranes. Recently it has been shown to also bind LPS-containing membranes and here we propose to study the interaction of Annexin A5 with PS and LPS using neutron reflectivity in order to better understand the structural requirements to turn Annexin A5 into a potentially effective antimicrobial therapy agent.