Immobilization of Fibronectin on Medical Grade Poly vinyl chloride

Immobilization of Fibronectin on Medical Grade Poly(vinyl chloride) 

The grafted polymer poly[(ethylene-co-vinyl acetate-co-carbon monoxide)-graft-vinyl chloride] (PVC/EVACO) known in medical applications as plasticized poly(vinyl chloride) was apphed as a carrier polymer for the covalent immobilization of fibronectin. The surface modifications were carried out on foils both with closed surface structure and with microporous surfaces produced by a phase-inversion technique. The vinyl acetate groups of the carrier polymer were saponified and then reacted with hexamethylene diisocyanate (HDI) as a spacer. Fibronectin is immobilized upon reaction of the free isocyanate group with an amino group of the protein (Fig. 33). The saponification of the carrier polymer was verified by IR-ATR and XPS [149]. The presence of hydroxyhc groups after hydrophihzation is demonstrated by a contact angle of 61° while that of the basic polymer is 110°. 

The coupling of HDI (5 d in diethyl ether at 250 °C) was proven by means of XPS, indicating a nitrogen content of 3.7 atom% and the urethane carbon. IR-ATR spectra show the characteristic absorption bands of the free isocyanate 

The covalent binding of fibronectin (10 pg/ml) was carried out in aqueous medium at pH 7.4. The amount of immobilized fibronectin was measured sem-iquantitatively by means of an ELISA technique. The values of fibronectin binding (via covalent bonds or adsorption) presented in Fig. 35 are given with reference to the TCPS surface. 

The effect of the modified PVC/EVACO surface on the proliferation behavior of human endothelial cells was investigated by means of endothelial cell seeding studies after 1,4 and 7 d (Fig. 36). While the endothelial cells show similar pro- 

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