Physicochemical Characterization of Sparsely Tethered Bilayer Lipid Membranes: Structure of Submembrane Water and Nanomechanical Properties

Sparsely tethered bilayer lipid membrane (stBLM) is a popular model considered to mimic biological membranes. The advantage of this system is the molecular architecture that provides a water environment on both sides of the lipid membrane. In this work, we have coupled electrochemical measurements with surface enhanced infrared absorption spectroscopy and atomic force microscopy to evaluate the effect of the electric field on the physicochemical properties of stBLM composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine and cholesterol. More specifically, we have focused on the structure of the submembrane water and nanomechanical properties of the membrane. Our experimental results revealed that stBLM composed of DMPC/Cholesterol offers good nanomechanical stability and low permeability within a relatively wide potential window. Importantly, it also covers biologically relevant range corresponding to transmembrane potentials occurring in natural cell membranes, which makes them suitable platform for bioinspired sensing devices.