Fabrication Of Micropatterned TiO₂Nanotube And Its Protein Adsorption/Cell Adhesion Behaviors

Due to excellent biocompatibility and high mechanical behavior, Ti-based materials asorthopedic and dental implant have been widely used in clinic areas. However, effective bonerepair under construction after implantation of Ti-based materials requires the provision oftopological cues on material surface to intrigue proper biological responses from surroundingenvironment, also to strengthen the combination between implants and bone tissue, which areoften realized by surface modification. Researches show that building topology structure, as asurface modification method can effectively regulate the response behaviors of biologicalmolecule, which contributes to the functionalization of biomaterials.In this paper, controllable micropatterned TiO₂nanotube arrays are fabricated on Tisurface via combination of photolithography and electrochemical anodization, by whichmicro-and nano-scales geometry control can be obtained. Two geometric patterns have beendesigned and established via photolithography on Ti. One is strip, the other is trapezium, ofwhich width （or inner diameter） and separation distance are100μm and200μm respectively.The preparation conditions are optimized and the interaction between micropatterning （viaphotolithography） and nanopatterning （via electrochemical anodization） processes isinvestigated in detail. Scanning electron microscope （SEM） and3D microscope were used toexamine the quantity and morphology of nano-and micro-scales geometric patterns. Crystalstructure of nanotube arrays were analyzed by X-ray diffractometer （XRD）. The results showthat anodization parameters, i.e. anodization voltage and anodization time, not only affect themorphology and size of TiO₂nanotube arrays, but also the micro-geometric patterns.Distortion of patterns could be severe when voltage is above25v, with oxidation time morethan30min. Amorphous TiO₂crystal transformed into the anatase crystal with little change ofmorphology after heat treatment at550℃for3hours.The resulting materials are then used for protein adsorption and cell adhesion test.Different initial concentration albumin from Bovine Serum （BSA） and Immunoglobulin G（IgG） were chosed to explore protein adsorption behavior at different adsorption time onmicropatterned TiO₂nanotube and Ti surface under the same condition. Microarray scannerand UV-Vis spectroscopy were applied for qualitative and quantitative determination ofprotein adsorption respectively. Results indicated that proteins were much more preffer TiO₂ nanotube than Ti. Besides, the protein adsorption quantity increased with the increasing of theprotein initial concentrations, whereas, saturation value always existed. All of above attributeto the larger specific surface area of TiO₂nanotube arrays provided to protein to adsorbcompare with Ti.It is found that protein adsorption and cell adhesion can “trace” the topological cues bypresenting high selectivity between micropatterned TiO₂nanotube and Ti surface.