Towards monitoring IAV-membrane interactions using SEIRA spectroscopy, we constructed a tBLM as a model for the host membrane using POPC with 1 mol% of GD1a as lipids (Figure and). GD1a is a ganglioside, which presents a sialic acid headgroup as the native IAV attachment factor and is, therefore, often used as specific IAV binding partner in interaction studies. The tBLM was tethered to the SEIRA Au film via the cholestanol-headed ChEO3SH, which we designed in our previous work (previously referred to as WK3SH) for spectroscopic studies on supported membrane systems. Mixing the tether with a spacer molecule, like 6-mercaptohexanol (6MH), creates a spontaneously phase-separated self-assembled monolayer, such that addition of lipid vesicles yields a planar tBLM with free-floating POPC-GD1a-containing lipid bilayer patches of roughly 150 nm diameter. To ensure that the tBLM has formed as intended, we followed the membrane formation spectroscopically and recorded the membrane capacitance (see Figure ).