Plasma-assisted heparin conjugation on electrospun poly(L-lactide) fibrous scaffolds

Abstract

Heparin conjugation on poly(L-lactide) fibrous scaffolds fabricated by electrospinning was accomplished by surface functionalization with amine (-NH2) groups using a sequential treatment with Ar-NH3 and H2 plasmas. The density of the incorporated -NH2 groups was determined by combining a chemical derivatization method with X-ray photoelectron spectroscopy. The time of Ar-NH3 plasma treatment significantly affected the N/C, -NH2 /N, and -NH2 /C fractions, whereas the plasma power, Ar-NH3 gas composition, and time of H2 plasma treatment only influenced the -NH2 /N and -NH2 /C fractions. Scaffold surface functionalization by -NH2 groups significantly increased the amount of covalently bonded heparin compared to a hydrolysis method. The function of immobilized heparin was confirmed by the decrease of platelet attachment during the exposure of the scaffolds to blood from Sprague-Dawley rats. In vitro experiments with bovine aorta endothelial cells demonstrated that heparin conjugation enhanced cell infiltration through the fibrous scaffolds, regardless of the amount of covalently immobilized heparin.

Keywords: amine groups; conjugation; endothelial cells; heparin; infiltration; plasma treatment; platelets; surface functionalization.