Protein adsorptive behavior on mesoporous titanium dioxide determined by geometrical topography

This work develops a linearly predictive model that investigates the relationship between the geometrical topography of mesoporous titanium dioxide (TiO₂) and protein adsorption at the isoelectric point. Proteins with different sizes, Bovine Serum Albumin, Myoglobin and Lysozyme, were employed as model molecules to analyze proein-TiO₂ interactions. Mesoporous TiO₂ surfaces with a range of pore sizes served as a model of topography were utilized as substrates to study the effects of topography on protein adsorption. By fitting the amount of adsorbed proteins to the varying geometrical topographies, a linear relationship was obtained to estimate the protein-surface interaction. It was found that the three proteins avidly adsorb on TiO₂ surface with strengthening coupling geometrical effects. The interaction between proteins and mesoporous TiO₂ with varying geometrical topographies was further examined by the adhesive force measurements via atomic force microscopy (AFM). The adsorption of protein Chicken Ovalbumin confirmed that the linear curve, describing protein-surface interaction, could be used as a general tool to predict protein adsorption at the isoelectric point. Furthermore, High-Performance Liquid Chromatography (HPLC) results at the macro-scale also demonstrated the accuracy of the predictive adsorption model. According to this model, TiO₂ surfaces with well-designed geometrical topographies can be constructed efficiently and expected for various applications such as fouling resistance, proteins separation and immobilization.