Dynamics of membrane adhesion: the role of polyethylene glycol spacers, ligand-receptor bond strength, and rupture pathway.
Biological 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.
Wong
Joyce Y
JY
Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, MA 02215, USA. jywong@bu.edu
Kuhl
Tonya L
TL
D001710:Biotin / Q000737:chemistry*; D002448:Cell Adhesion / Q000502:physiology; D008024:Ligands; D008051:Lipid Bilayers / Q000737:chemistry*; D008954:Models, Biological; D015394:Molecular Structure; D010714:Phosphatidylethanolamines / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D019809:Streptavidin / Q000737:chemistry*; D013499:Surface Properties
D008024:Ligands; D008051:Lipid Bilayers; D010714:Phosphatidylethanolamines; C038089:1,2-distearoylphosphatidylethanolamine; D011092:Polyethylene Glycols; C007445:1,2-dilauroylphosphatidylethanolamine; D001710:Biotin; D019809:Streptavidin