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Dynamics of Membrane Adhesion: The Role of Polyethylene Glycol Spacers, Ligand−Receptor Bond Strength, and Rupture Pathway†
journal contribution
posted on 2008-02-19, 00:00 authored by Joyce Y. Wong, Tonya L. KuhlBiological adhesion typically occurs through discrete cross bridges between complementary molecules on adjacent
membranes. Here we report quantitative measurements of the binding distance between a lipid membrane functionalized
with ligands on flexible polymer tether chains and a second membrane bearing complementary receptors using the
surface force apparatus technique. The binding distance is shown to increase as a function of polymer tether length.
Upon separation, adhesive failure occurs not at the strong ligand−receptor bond but primarily through the mechanical
pullout of cross-bridging polymer tethers from the membrane. We summarize these measurements of complementary
membrane adhesion dynamics using an energy-state diagram that encompasses the energetics of the polymer tether,
ligand−receptor bond strength, and number of cross bridges formed.