Study of haemodialysis materials; physico-chemical and biological characterization of EVALVA, EVAPA and heparinized EVAPA

Partially hydrolyzed ethylene/vinyl acetate copolymers were modified by the covalent binding of a heparin-complexing polymer and further heparinized in order to improve their blood compatibility. These heparinizable polymeric materials (EVAPA) were obtained by a two-step reaction between an ethylene/vinyl alcohol/vinyl acetate (EVALVA) terpolymer, and the heparin complexing polymer N2LL. The physico-chemical characterization of EVALVA, EVAPA and heparinized-EVAPA was carried out through thermal analysis, SEM, contact angle, potentiometric measurements, water uptake and FT-IR spectroscopic measurements. The biocompatibility of the above-mentioned samples was evaluated usingin vitro methods, through the determination of heparin release in phosphate buffer solution (PBS) and in human plasma, and with the investigation of hemostasis activation.