Adsorption of bovine serum albumin onto titanium dioxide nanotube arrays

Titanium dioxide nanotube arrays on titanium were fabricated via anodic oxidation and heat treatment. The diameters of nanotubes ranged from 20 to 200 nm, and the lengths were 500 and 1000 nm. The adsorption behavior of bovine serum albumin onto the nanotube arrays was investigated. Surface characterization for samples was carried out using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Adsorbance of bovine serum albumin was detected with an ultraviolet spectrophotometer. The results showed that the nanotube arrays on titanium surfaces significantly enhanced bovine serum albumin adsorption. The nanotube arrays with larger diameter could adsorb more bovine serum albumin, but longer nanotubes showed less adsorbance than shorter nanotubes. In the present work, the nanotube arrays with 160-200 nm diameter, the largest diameter, showed the highest adsorption ability, and the maximum adsorption capacity q(m) was 31.40 mg . cm(-2). In addition, the adsorbance of bovine serum albumin increased with increase of initial bovine serum albumin concentrations, and a saturation value was achieved at the initial bovine serum albumin concentration of 2.0 mg . ml(-1).