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P. Bilotto, M. Lengauer, J. Andersson, U. Ramach, L. Mears, M. Valtiner:
"Interaction profiles and stability of rigid and polymer-tethered lipid bilayer models at highly charged and highly adhesive contacts";
Langmuir, 35 (2019), 48; 15552 - 15563.

Understanding interaction force versus distance
profiles of supported lipid bilayers (SLBs) is relevant to
a number of areas, which rely on these model systems,
including, e.g., characterization of ligand/receptor interactions
or bacterial adhesion. Here, the stability of 4 different SLB
architectures was compared using the surface forces apparatus
(SFA) and atomic force microscopy (AFM). Specifically, the
outer envelope of the bilayer systems remained constant as
1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). The
inner layer was varied between DPPC and 1,2-dipalmitoyl-3-
trimethylammonium-propane (DPTAP) both on mica, and
self-assembled monolayers (SAMs) of hexadecanethiol and the polymer-tethered diphytanylglycerol-tetraethylene glycol-lipoid
acid (DPhyTL) on smooth gold surfaces. In that same order these gave an increasing strength of interaction between the inner
layer and the supporting substrate and hence improved stability under highly adhesive conditions. Detachment profiles from
highly charged and highly adhesive contacts were characterized, and approach characteristics were fitted to DLVO models. We
find increasing stability under highly adhesive loads, approaching the hydrophobic limit of the adhesive energy between the
inner and outer layers for the SAM-based systems. For all four SLBs we further compare AFM surface topographies, which
strongly depend on preparation conditions, and the DLVO fitting of the SFA approach curves finds a strong charge regulation
behavior during interaction, dependent on the particular model system. In addition, we find undulation characteristics during
approach and separation. The increased stability of the complex architectures on a gold support makes these model systems an
ideal starting point for studying more complex strongly adhesive/interacting systems, including, for example, ligand/receptor
interactions, biosensing interactions, or cell/surface interactions.

http://dx.doi.org/10.1021/acs.langmuir.9b01942

https://publik.tuwien.ac.at/files/publik_283638.pdf