title: Adhesion and activation of platelets and polymorphonuclear granulocyte cells at TiO2 surfaces.
abstract: The initial reactions of two TiO2 surfaces with blood were investigated by short-time exposure to capillary blood and analysis of surface-adsorbed plasma proteins and surface-adhering cells by using immunofluorescence techniques. Antibodies directed against platelet membrane antigen and P-selectin were used to visualize platelet adhesion and activation. Acridine orange and anti-CD11b were used to detect adhesion and activation of polymorphonuclear granulocytes (PMNs). Antibodies against thrombospondin were used as markers for platelet alpha-granules. The fluorescence intensity was quantitated by computer-aided image analysis. Commercially pure, polished sheet titanium was oxidized in two different ways: (1) the natural oxide was dissolved with hydrofluoric acid and a new oxide layer was grown by oxidation in nitric acid, or (2) annealing was performed at 700 degrees C in air. Auger electron spectroscopy and x-ray photoelectron spectroscopy showed that both surfaces had similar composition consisting of TiO2 covered by a carbonaceous surface contamination layer. The thickness of the oxide layer was 4 nm on the acid-oxidized surface and 39 nm on the annealed surface. Optical profilometry and scanning electron microscopy showed that the acid-oxidized surface was rough and the annealed surface was smooth. The fibrinogen/prothrombin-thrombin ratio in the initial protein film differed between the surfaces. The number of adhering platelets was larger at the surface with a high surface concentration of adsorbed fibrinogen. Platelet activation (CD62) and priming of PMNs (CD 11b) were also significantly higher on the acid-oxidized surface. The results indicate that non-self recognition of biomaterials is an array of transient reactions comprising protein-material, protein-cell, and cell-cell interactions.
authors.affiliation: Department of Anatomy and Cell Biology, University of Göteborg, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Nygren
authors.forename: C
authors.initials: C
authors.lastname: Eriksson
authors.forename: J
authors.initials: J
authors.lastname: Lausmaa
mesh_terms: D001672:Biocompatible Materials; D015415:Biomarkers; D001779:Blood Coagulation Factors / Q000737:chemistry; D001792:Blood Platelets / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D016177:Macrophage-1 Antigen / Q000096:biosynthesis; D008855:Microscopy, Electron, Scanning; D009504:Neutrophils / Q000502:physiology*; D019007:P-Selectin / Q000096:biosynthesis; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D015415:Biomarkers; D001779:Blood Coagulation Factors; D016177:Macrophage-1 Antigen; D019007:P-Selectin; C009495:titanium dioxide; D014025:Titanium