Integrin and glycocalyx mediated contributions to cell adhesion identified by single cellforce spectroscopy

Abstract

The measurement of cell adhesion using single cell force spectroscopy methods wascompared with earlier methods for measuring cell adhesion. This comparison provided ameans and rationale for separating components of the measurement retract curve that weredue to interactions between the substrate and the glycocalyx, and interactions that weredue to cell surface integrins binding to a substrate-bound ligand. The glycocalyx adhesionwas characterized by multiple jumps with dispersed jump sizes that extended from 5 to30 µm from the origin. The integrin mediated adhesion was represented by theFmax (maximum detachment force), was generally within the first5 µm and commonly detached with a single rupture cascade. The integrin peak (Fmax) increases with time and the rate of increase shows large cell to cell variability with a peak ∼ 50 nN s − 1 and an averagerate of increase of 75 pN s − 1. This is a measure of the rate of increase in the number of adhesive integrin–ligandbonds/cell as a function of contact time.