Model for measurement of water layer thickness under lipid bilayers by surface plasmon resonance

A multilayered-substrate model is proposed for surface plasmon resonance (SPR)-based measurement of the thickness of a water layer sandwiched between a lipid bilayer and an underlying support. To calculate sensitivity, a 473 nm-wavelength excitation source and a silver layer are used for the SPR sensor. It is theoretically shown that the multilayered substrate design achieves sufficient sensitivity for such measurements and that sensitivity is enhanced with a SiO(2) layer of appropriate thickness and a buffer solution of high refractive index.