Open Access

ARTICLE

Stability of Molecular Adhesion Mediated by Confined Polymer Repellers and Ligand-Receptor Bonds

Jizeng Wang^*, Jin Qian^*, Huajian Gao^∗,†

* The Division of Engineering, Box D, Brown University, 182 Hope Street, Providence, RI 02912, USA
† Corresponding author. Tel.: +1 401 863 2626; Fax: +1 401 863 9025; E-mail: Huajian_Gao@Brown.edu

Molecular & Cellular Biomechanics 2008, 5(1), 19-26. https://doi.org/10.3970/mcb.2008.005.019

Abstract

Experiments have shown that stable adhesion of a variety of animal cells on substrates prepared with precisely controlled ligand distribution can be formed only if the ligand spacing is below 58 nm. To explain this phenomenon, here we propose a confined polymer model to study the stability of molecular adhesion mediated by polymer repellers and ligand-receptor bonds. In this model, both repellers and binders are treated as wormlike chains confined in a nanoslit, and the stability of adhesion is considered as a competition between attractive interactions of ligand-receptor binding and repulsive forces due to the size mismatch between repellers and binders. The force on each ligand-receptor bond is calculated from the confined polymer model, and the classic model of Bell is used to describe the association/dissociation reactions of ligand-receptor bonds. The calculated equilibrium bond distribution shows that there exists a critical ligand density for stable adhesion, corresponding to a critical ligand spacing which agrees not only qualitatively but also quantitatively with the experimental observation. In the case of stable adhesion, the model predicts an equilibrium separation between adhesion surfaces below 60{\%} of the contour length of the ligand-receptor bonds.

---