| AVS 54th International Symposium | |
| Understanding Biointerphases and Magnetism with Neutrons Topical Conference | Wednesday Sessions |
| Session NT+BI-WeM |
| Session: | Phospholipid Bilayers and Membranes |
| Presenter: | M. Lösche, Carnegie Mellon University |
| Authors: | M. Lösche, Carnegie Mellon University F. Heinrich, Carnegie Mellon University D.J. McGillivray, The Australian National University G. Valincius, Institute of Biochemistry, Vilnius, Lithuania Y. Sokolov, UC Irvine J.E. Hall, UC Irvine |
| Correspondent: | Click to Email |
Tethered bilayer lipid membranes (tBLMs) on solid supports hold potential to mimic biological membranes. Molecular-scale studies of the interactions of peptides and proteins with membranes provide ample opportunities in biophysical and biomedical research. Membrane stabilization by the proximity of a solid substrate provides resilience to the system, but has often at the same time introduced severe problems. A prerequisite, for example, for tBLM characterization by scattering and electrochemical techniques is a low defect density of the membrane. Only then is it possible to quantify minor structural and functional changes induced by, e.g., protein interaction with the membrane. We have optimized a membrane architecture on molecularly flat gold surfaces which meets all these challenges. Different lengths of the hydrophilic poly(ethylene glycol) (PEG) spacer that controls the structure of the inner monolayer leaflet provide highly hydrated sub-membrane spaces between 20 Å and 60 Å in thickness, as determined by neutron reflection. Such tBLMs may be composed of charged or zwitterionic lipids with various chain saturation, and can include cholesterol. The membranes are highly insulating and are routinely probed with electrochemical impedance spectroscopy (EIS). As an example for ongoing biomedical research we will discuss the interaction of soluble prefibrillar β-amyloid oligomers with tBLMs and compare the impact of the peptide on such membranes with that of a pore forming bacterial exotoxin, Staphylococcus aureus α-hemolysin.