Study On Modified TiO₂ Nanotube Arrays Load With Drug And Its Release Behavior

In recent years,the regular morphology and vertically aligned highly ordered TiO₂ nanotube arrays on Ti surface were prepared via a self-ordering electrochemical anodization have attracted remarkable attention.Ti02 nanotube arrays possess unique properties including large specific surface area,excellent biocompatibility,controllable dimensions and strong adsorption ability;therefore,they exhibit good application prospect in biomedical field.Studies have demonstrated that TiO₂ nanotube arrays as orthopedic implants can promote osteointegration.Moreover,TiO₂ nanotube arrays are also used as local drug delivery/releasing system in bone implants to enhance antibacterial and anti-inflammatory properties which are desirable for the prevention of implant associated infection.TiO₂ nanotube arrays of different morphologies were fabricated by anodic oxidation and used as drug carrier in this paper.To explore the morphology and surface properties of TiO₂ nanotube arrays impact on its drug loading capacity and release behavior.drugs.Ibuprofen?IBU?was selected as a model drug.Ibuprofen is a nonsteroidal anti-inflammatory drug which can improve the resistance to infection and treatment of various moderate pain and inflammation.Clinically,it is mainly used for treating rheumatoid arthritis and osteoarthritis.Firstly,TiO₂ nanotube arrays of different morphologies were preparation by anodic oxidation in the electrolytes containing F-,one is high order with close packed structure and the other one with large void space structure.In order to study the load capacity and release behavior of ibuprofen on the two different morphologies of TiO₂ nanotubes,Ibuprofen were loaded into TiO₂ nanotube arrays by vacuum drying method and then in vitro release.Then the uniformly distributed layer of P25 nanoparticles decorated on arrays was prepared by the hydrothermal treatment.P25 NPs decorated on TiO₂ nanotube led to a significant increased in the specific surface area of TNTs which was conducive to improve the loading effect of IBU.Importantly,the reduced in diameters and the increased in roughness of the nanotubes were led to an effective and prolonged drug release.The morphology and phase of TiO₂ nanotube arrays were characterized by means of SEM,XRD,FTIR.To further enhance the interaction between the nanotube surface and the ibuprofen molecules and extend drug release.APTES?3-Aminopropyltriethoxysilane?was grafted on the surface of TiO₂ nanotube arrays before loading ibuprofen.The APTES grafting on TiO₂ nanotube can enhance the binding capacity of the nanotube surface and the drug molecule by forming chemical bond with ibuprofen.The interactions mode of chemical bonding between TiO₂ nanotube arrays surface and APTES were analyzed by XPS and FTIR.The results indicated that,the mode of interaction of APTES and TiO₂ nanotube surface is the silane groups react with hydroxyl groups present on the TiO₂ nanotube surface to form a silanized surface,then formed free terminal-NH2 groups,which away from the TiO₂ nanotube surface.At pH 5.3,the-COO-group of the ibuprofen molecules and the-NH3+ group of the APTES molecules formed the-COO--NH3+ bond,which can enhance the drug adsorption capacity of TiO₂ nanotube arrays and improve extend drug release.