This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.107.105544v1 93/9/3300    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Limozin, L. Articles by Sengupta, K. Search for Related Content PubMed PubMed Citation Articles by Limozin, L. Articles by Sengupta, K.

Modulation of Vesicle Adhesion and Spreading Kinetics by Hyaluronan Cushions

Laurent Limozin ^* and Kheya Sengupta 

^* Adhésion Cellulaire, Centre National de la Recherche Scientifique UMR 6212, INSERM U600, Université de la Mediterranée, Luminy, Marseille, France; and Institut für Bio- und Nanosysteme-4 (Biomechanics), Forschungszentrum, Jülich, Germany

Correspondence: Address reprint requests to K. Sengupta, E-mail: k.sengupta{at}fz-juelich.de.

The adhesion of giant unilamellar phospholipid vesicles to planar substrates coated with extracellular matrix mimetic cushions of hyaluronan is studied using quantitative reflection interference contrast microscopy. The absolute height of the vesicle membrane at the vicinity of the substrate is measured by considering, for the first time, the refractive indices of the reflecting media. The thickness of the cushion is varied in the range of 50–100 nm, by designing various coupling strategies. On bare protein-coated substrates, the vesicles spread fast (0.5 s) and form a uniform adhesion disk, with the average membrane height 4 nm. On thick hyaluronan cushions (>80 nm), the membrane height is approximately the same as the thickness of the cushion, implying that the vesicle lies on top of the cushion. On a thin and inhomogeneous hyaluronan cushion, the adhesion is modified but not prevented. The spreading is slow (20 s) compared to the no-cushion case. The average membrane height is 10 nm and the adhesion disk is studded with blisterlike structures. Observations with fluorescent hyaluronan indicate that the polymer is compressed under, rather than expelled from, the adhesion disk. The adhesion energy density is approximately threefold higher in the no-cushion case (1.2 µJ/m²) as compared to the thin-cushion case (0.54 µJ/m²). In the thin-cushion case, the presence of short (4 nm) glyco-polymers on the vesicles results in a hitherto unreported stable partial adhesion state—the membrane height ranges from zero to 250 nm. The minimal model system presented here mimics in vitro the hyaluronan-modulated early stages of cell adhesion, and demonstrates that the presence of a polymer cushion influences both the final equilibrium adhesion-state and the spreading kinetics.

This article has been cited by other articles:

				P. Robert, K. Sengupta, P.-H. Puech, P. Bongrand, and L. Limozin Tuning the Formation and Rupture of Single Ligand-Receptor Bonds by Hyaluronan-Induced Repulsion Biophys. J., October 15, 2008; 95(8): 3999 - 4012. [Abstract] [Full Text] [PDF]