(331b) Biochemo-Mechanics of Macromolecular Interactions with Lipid Membranes Studied with Microcantilevers

I will describe how biochemical interactions are translated into a nanomechanical measurements: biochemo-mechanics. Specificially, supported lipid–membranes on microcantilevers are used to probe the interactions between phospholipid membranes and membrane-active macromolecules. This sensing method integrates two well-developed techniques: the solid-supported lipid bilayers (SLBs) and the microcantilever sensors. As lipids and macromolecules adsorb onto the surface of the microcantilever, it induces a nanomechanical deflection of the microcantilever due to induced compressive or tensile surface stresses. By monitoring this nanomechanical deflection, the real–time surface stress changes in supported lipid membranes can be detected. Macromolecules, such as PEP1, a synthetic amphipathic peptide resembling a segment of the nonstructural protein (NS5A) of hepatitis C virus, and Pluronics with lipid membranes cause a measurable deflection change. In both systems, we are able to observe macromolecules adsorb onto and crowd the lipid membranes. For concentration greater than the critical concentration, the macromolecules start to aggregate leading to membrane pore formation. At even higher concentrations, the macromolecules further destabilize and induce the solubilization of membrane. The membrane coated microcantilever sensor is capable of characterizing the kinetics and dynamics of membrane-peptide interactions with great sensitivity.