Heparinization of gas plasma-modified polystyrene surfaces and the interactions of these surfaces with proteins studied with surface plasmon resonance

• Published in: Biomaterials Vol. 18; no. 12; pp. 845 - 852
• Main Authors: van Delden, C.J., Lens, J.P., Kooyman, R.P.H., Engbers, G.H.M., Feijen, J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-06-1997; Elsevier Science
• Subjects: Albumins; Animals; Antithrombin III; Argon; Biocompatible Materials; Biological and medical sciences; Heparin; heparinization; Materials Testing; Medical sciences; Polystyrenes; protein-surface interactions; Proteins; Rabbits; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Surface plasmon resonance; Surface Properties; Technology. Biomaterials. Equipments. Material. Instrumentation; Thrombin; protein-surface interactions; heparinization; Surface plasmon resonance; Plasma gas; Hemostatic; Serine endopeptidases; Enzyme; Interaction; Albumin; Immobilization; Thrombin; Anticoagulant; Surface plasmon; Coated material; Surface treatment; Concentration measurement; Proteins; Peptidases; Plasma resonance; Hydrolases; Glycosaminoglycan; Structure modification; Styrene polymer; Biomaterial; Heparin; Technique
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/S0142-9612(96)00209-8

Polystyrene surfaces obtained by spin-coating a solution of polystyrene in toluene on a gold layer were functionalized with carboxylic acid groups by preadsorption of the sodium salt of undecylenic acid, followed by an argon plasma treatment. A conjugate of albumin and heparin (alb-hep) was covalently immobilized onto the functionalized surface via preactivation of carboxylic acid groups with a water-soluble carbodiimide. The immobilization of alb-hep conjugate and the subsequent interactions of the heparinized surface with antithrombin III (ATIII, a heparin cofactor) and thrombin were monitored with surface plasmon resonance (SPR). The surface concentration of conjugate as determined with SPR deviated quantitatively from the results obtained with radiolabelled conjugate. The difference in surface concentrations of conjugate obtained with the two methods probably originates from the uncertainty of the refractive index of the alb-hep conjugate in the SPR technique. ATIII could be bound to the surface modified with alb-hep conjugate but not to a polystyrene surface modified with albumin. Rabbit anti-human ATIII did bind to the alb-hep surface previously exposed to ATIII, confirming the presence of surface bound ATIII. The alb-hep immobilized surface was able to bind much more thrombin than ATIII, which is probably due to the less specific heparin-thrombin interaction as compared to the heparin-ATIII interaction. This study shows that SPR is a technique that can be used to study, in real time, both the modification of polymer surfaces and the subsequent interactions of the modified surfaces with proteins.