Endothelial cell adhesion force estimation at the nanoscale

Endothelial cell adhesion to a synthetic surface includes a definite set of molecular interactions. Cell adhesion is managed by fibronectin and vitronectin in extracellular matrix (ECM) that binds the receptor site of the trans-membrane protein dimers, the integrins. These proteins contain one of the binding sites (I-like domain receptor) for the Arg-Gly-Asp (RGD) peptides that are the established adhesion receptor sites in the ECM. A molecular approach can quantify the adhesion strength by ligand-receptor force computation. The molecular interaction energy between a polyethylene (PE) surface covalently grafted with the adhesion sites (RGD-containing) and trans-membrane integrin receptor (I-domain) was evaluated through a molecular model of a single ligand-receptor complex. The aims of this work were: (i) the generation of the receptor molecular model: the I-like domain; (ii) the evaluation of the greatest binding chemical affinity between the I-like domain and three RGD-containing peptides; (iii) the development of the molecular model of crystalline lamellae of PE; and (iv) the evaluation of the interac-tion energies and the interaction force between the I-like domain and the grafted biomaterial. The calculation of the interaction energies can provide an estimation of the adhesion force of the ligand-receptor complex and, finally, of the endothelial cell adhesion force. The calculated cell adhesion force is in agreement with experimental data.(Journal of Applied Biomaterials and Biomechanics 2005; 3: 42-9).