Preparation RhBMP-2Loaded Chitosan Microsphere Coated Nitinol And Its Properties In Vitro

Objective:Fabrication rhBMP-2sustained-release coating on the nitinol’s surface which have been oxidized. Detection release function of rhBMP-2and evaluate the effect of rhBMP-2on the biological behavior of mouse osteoblast.Methods:NiTi alloy was heated to500degrees Celsius not less than10min. And the surface was analyzed by XRD. Chitosan/rhBMP-2coated on the film with porous PAA/PAH which have been fabricated by self-assembly and dissolution methods. Each step was observed under the scanning electronic microscope. The contact-angle measurement was employed to characterize the difference of wetting between the untreated surface and the treated one. Steep with the material into simulated body fluid, enzyme-linked immunosorbent assays was detected the velocity of protein release. Hemolysis and dynamic clotting time were utilized to investigate the biocompatibility of the coated NiTi alloy. And alkaline phosphatase (ALP) activity was evaluated in different times with the same technique after the osteoblast in vitro.Result:By XRD it has been found TiO2film to formed on the surface after heated in500℃, SEM found with micron to nanometer holes have been fabrication after the PAA/PAH coating steep in hydrochloric acid, and the holes have been fixed and coating after impregnated with Chitosan/rhBMP-2’ solution. The contact angles measurement shown that the hydrophilic character of the modified surfaces was increased in comparison with untreated NiTi. With the increase of soaking time, rhBMP-2was gradually increased, and the activity of ALP in cell-culture medium was obviously increased. Hemolysis and dynamic clotting time showed the blood compatibility improved.Conclusion:Chitosan/rhBMP-2/PAH/PAA/Nitinol have been fabricated, biocompatibility is improved and rhBMP-2have sustained-release property, it has positive effects on osteoblast growth.