title: Tailoring of the titanium surface by immobilization of heparin/fibronectin complexes for improving blood compatibility and endothelialization: an in vitro study.
abstract: To improve the blood compatibility and endothelialization simultaneously and to ensure the long-term effectiveness of the cardiovascular implants, we developed a surface modification method, enabling the coimmobilization of biomolecules to metal surfaces. In the present study, a heparin and fibronectin mixture (Hep/Fn) covalently immobilized on a titanium (Ti) substrate for biocompatibility was investigated. Different systems [N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide and N-hydroxysuccinimide, electrostatic] were used for the formation of Hep/Fn layers. Atomic force microscopy (AFM) showed that the roughness of the silanized Ti surface decreased after the immobilization of Hep/Fn. Fourier transform infrared spectroscopy (FTIR), Toluidine Blue O (TBO) test, and immunochemistry assay showed that Hep/Fn mixture was successfully immobilized on Ti surface. Blood compatibility tests (hemolysis rate, APTT, platelet adhesion, fibrinogen conformational change) showed that the coimmobilized films of Hep/Fn mixture reduced blood hemolysis rate, prolonged blood coagulation time, reduced platelets activation and aggregation, and induced less fibrinogen conformational change compared with a bare Ti surface. Endothelial cell (EC) seeding showed more EC with better morphology on pH 4 samples than on pH 7 and EDC/NHS samples, which showed rounded and aggregated cells. Systematic evaluation showed that the pH 4 samples also had much better blood compatibility. All results suggest that the coimmobilized films of Hep/Fn can confer excellent antithrombotic properties and with good endothelialization. We envisage that this method will provide a potential and effective solution for the surface modification of cardiovascular implant materials.
authors.affiliation: Institute of Biomaterials and Surface Engineering, Key Laboratory for Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, PR China.
authors.forename: Guicai
authors.initials: G
authors.lastname: Li
authors.forename: Ping
authors.initials: P
authors.lastname: Yang
authors.forename: Yuzhen
authors.initials: Y
authors.lastname: Liao
authors.forename: Nan
authors.initials: N
authors.lastname: Huang
mesh_terms: D001672:Biocompatible Materials; D001792:Blood Platelets / Q000166:cytology / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000166:cytology*; D005353:Fibronectins / Q000737:chemistry*; D006493:Heparin / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D005353:Fibronectins; D006493:Heparin; D014025:Titanium