Surface roughness, albumin adsorption and thrombogenicity of cellulose-blended polyurethane membranes

Polyurethanes (PUs) are synthetic polymers with easily adaptable mechanical properties to many medical applications, including those in which contact with blood is required. Not all PUs are haemocompatible even if they are not cytotoxic. In this study PUs obtained from poly(ethylene adipate)diol (PEGA), polytetrahydrofuran (PTHF) or poly(propylene)glycol (PPG) as soft segments and 4´,4´-diphenylmethanediisocyanate were blended with hydroxypropylcellulose (HPC). The investigation of the functional integration capacity to blood interface of the newly prepared materials was performed. Surface analysis (by atomic force microscopy - AFM), determination of albumin adsorption (by immunochemical mono-specific method) and amount of cloth formed after in vitro exposition to the blood (by clot weight test) were done. The initial surface roughness of the materials was between 62 nm and 82 nm, but this may change after incubation with blood plasma. We found that the thrombogenic action of PUs depends on surface charge, hydrophilicity and albumin adsorption capacity. The most haemo-adaptable samples were those which had neutral surface charge, high amount of adsorbed albumin and surface remodeling capacity after blood interaction. In our study these properties was provided by polyurethane with PTHF as soft segment.