M n (kDa) Ɖ (HA-g-Lac) formed by the method of vesicle spreading, and reproduce salient properties of the cell membrane, notably the lipid bilayer organization and fluidity allowing diffusion of lipids and attached proteins and/or glycopolymers in the membrane plane. The lipid composition can be readily varied to build desired functions into SLBs. In our case, the SLBs contained mostly phospholipid DOPC, to provide a background that is resistant to non-specific binding of most proteins, along with a small fraction of synthetic lipids designed to attach the mucin-like glycopolymers via their biotin. A streptavidin (SAv) monolayer was added (Figure ) to link the biotin on mucin-like glycopolymers to biotin-presenting lipids. In solution, and when surface-anchored at low coverage (Figure ③), the mucin-like glycopolymers are expected to form random coils; as the surface coverage increases the individual molecules will repel each other and entail stretching of the HA backbone and formation of a 'brush' morphology (Figure ). QCM-D was used to monitor the assembly of glycocalyx models. QCM-D is sensitive to the mass/thickness and mechanical properties of surface adlayers. To a first approximation, a negative shift in resonance frequency (ΔF) relates to an increase in mass (including hydrodynamically coupled solvent), and a positive dissipation shift (ΔD) is a measure of adlayer softness. QCM-D data in Figure are for the formation of a (HA-g-Lac L )-B brush. The biphasic response upon exposure of small unilamellar vesicles (SUVs) to the QCM-D sensor surface (Figure ; 13 to 23 min) is characteristic of SUVs initially binding intact, followed by their rupture and coalescence into a SLB. The extrema in ΔD and ΔF here arise from the SUV layer being softer and trapping more solvent, respectively, than the final SLB. The net frequency shift at the end of SUV exposure (ΔF = -25±1 Hz) reveals a film thickness of 4.5 nm, as expected for a hydrated lipid bilayer, and the close-to-zero net dissipation shift (ΔD < 0.5 × 10 -6 ) indicates the SLB is of good quality (i.e., with minimal residual surface-bound SUVs). Exposure to SAv (Figure ; 45 to 55 min) led to a further decrease in frequency (ΔF = -24±1 Hz) and a relatively small increase in dissipation (ΔD = 0.6 × 10 -6 ), consistent with the formation of a protein monolayer of 4 nm thickness. Indeed, with 5 mol% of biotin-presenting lipids in the SLB, a dense monolayer of SAv is expected to form. Binding was clearly observed when (HA-g-Lac L )-B was flowed over the SAv-on-SLB surface, whereas there was no measurable response for HA-g-Lac L (Figure ; 72 to 88 min; lines with circle and triangle symbols, respectively). This demonstrated specific anchorage of the mucin-like structure via its biotin tag. The responses for (HA-g-Lac L )-B were saturable (ΔF = -40 Hz and ΔD = 6.8 × 10 -6 ) and unchanged upon rinsing with buffer, indicating full occupation and stable binding to the biotin binding sites on the surface.