title: Fibrinogen adsorption and platelet interactions on polymer membranes.
abstract: The hemocompatibility of four different wettable polymer membranes, namely Cuprophan (CE), polyether-polycarbonate (PC-PE), polysulfone (PSU), and polyetherimide (PEI), was investigated with respect to fibrinogen (Fng) adsorption and platelet adhesion/activation. In order to estimate the polar and dispersion components of the surface free energy, contact angles using water/vapor and water/n-hexadecane systems were measured. Adsorption of fibrinogen was studied using fluorescence-labeled protein. The adsorption isotherms showed that the amount and the affinity of adsorbed Fng increased with decreasing surface wettability of the membranes, which correlates with the dispersion and polar components of the surface free energy. The conformational changes of adsorbed Fng were detected by measuring the difference between monoclonal antibody binding to the conformation-sensitive epitope in the D-domain and the binding of polyclonal anti-Fng antibody. The anticipated conformational/orientational changes were greater for PEI and PSU membranes (the least wettable membranes) and negligible for the more wettable PC-PE and CE membranes. In addition, a possible relationship with the degree of platelet activation was found, showing negligible platelet adhesion on PC-PE and CE, but high platelet adhesion on PEI and PSU. Furthermore, platelets were spread to a large extent on PEI, while the formation of aggregates was observed on PSU. This may correspond to the anticipated differences in the conformational state of Fng on both membranes.
authors.affiliation: GKSS Forschungszentrum, Institut für Chemie, Abteilung Membranforschung, Teltow, Germany.
authors.forename: Rumiana
authors.initials: R
authors.lastname: Tzoneva
authors.forename: Matthias
authors.initials: M
authors.lastname: Heuchel
authors.forename: Thomas
authors.initials: T
authors.lastname: Groth
authors.forename: George
authors.initials: G
authors.lastname: Altankov
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Albrecht
authors.forename: Dieter
authors.initials: D
authors.lastname: Paul
mesh_terms: D000327:Adsorption; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D008567:Membranes, Artificial; D018613:Microscopy, Confocal; D010974:Platelet Aggregation / Q000502:physiology*; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017155:Wettability
chemical_list: D001672:Biocompatible Materials; D008567:Membranes, Artificial; D011108:Polymers; D005340:Fibrinogen