Stiffness and heterogeneity of the pulmonary endothelial glycocalyx measured by atomic force microscopy

Ryan O'Callaghan, Kathleen M. Job, Randal O. Dull, Vladimir Hlady

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


The mechanical properties of endothelial glycocalyx were studied using atomic force microscopy with a silica bead (diameter ~18 μm) serving as an indenter. Even at indentations of several hundred nanometers, the bead exerted very low compressive pressures on the bovine lung microvascular endothelial cell (BLMVEC) glycocalyx and allowed for an averaging of stiffness in the bead-cell contact area. The elastic modulus of BLMVEC glycocalyx was determined as a pointwise function of the indentation depth before and after enzymatic degradation of specific glycocalyx components. The modulus-indentation depth profiles showed the cells becoming progressively stiffer with increased indentation. Three different enzymes were used: heparinases III and I and hyaluronidase. The main effects of heparinase III and hyaluronidase enzymes were that the elastic modulus in the cell junction regions increased more rapidly with the indentation than in BLMVEC controls, and that the effective thickness of glycocalyx was reduced. Cytochalasin D abolished the modulus increase with the indentation. The confocal profiling of heparan sulfate and hyaluronan with atomic force microscopy indentation data demonstrated marked heterogeneity of the glycocalyx composition between cell junctions and nuclear regions.

Original languageEnglish (US)
Pages (from-to)L353-L360
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number3
StatePublished - Sep 2011


  • Atomic force microscopy
  • Bovine lung microvascular endothelial cell
  • Heparan sulfate
  • Hyaluronan

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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