AFM Manipulation Of Small Fibrin Networks

Nathan E. Hudson, Daniel C. Millard, John Houser, E. Timothy O'Brien, Susan T. Lord, Richard Superfine, Michael R. Falvo
2009 Biophysical Journal  
increasing load. Little, however, is known about the mechanics of E-selectin bonds with its ligands. We tested the load-dependence of bond rupture for Eselectin, and its dependence on the history of load application, by using the distribution of load between multiple receptor-ligand bonds to create a complex loading history. Briefly, an E-selectin-coated bead was held in a laser trap and touched to the vertical surface of a bead coated with sialyl lewis A (sLe a ), allowing one or more bonds to
more » ... form with the ligand-coated surface. The laser trap was deflected away from the trapped bead, applying a nearly instantaneous load. When multiple bonds were present, we were able to discern the rupture of each bond as a step displacement of the trapped bead away from the stationary bead. In this way we were able to monitor both the number of bonds and the lifetime of each bond. We assumed that the load was evenly distributed between bonds and were thus able to monitor bond lifetimes across complex loading histories as the bonds ruptured asynchronously. Our data suggests that E-selectin/sLe a bonds behave as catch-slip bonds with critical forces of approximately 35 pN. Further, the lifetime of single bonds is similar to the lifetime of bonds that have previously shared load with others. This implies that E-selectin/sLe a bonds do not display strong force history-dependence. Rather, the bond lifetime is determined solely by the instantaneous load on the bond.
doi:10.1016/j.bpj.2008.12.092 fatcat:6xndpg5zjrdgdodbajo7q5z4ou