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.