Influence of the titania nanotubes dimensions on adsorption of collagen: an experimental and computational study

To investigate the influence of the titanium nanotube (TiNT) diameters on the adsorption of collagen type I (Col-I), TiNTs with different diameters were prepared with anodization. The adsorption amount of Col-I on the different TiNTs substrates was evaluated by spectrophotometric measurement and immunofluorescence staining, respectively. The results showed that the diameters of TiNTs played a key role in the adsorption process of Col-I. TiNTs with diameters around 100nm displayed a higher adsorption amount and faster adsorption speed than that of 30nm TiNTs. Furthermore, more collagen molecules were aggregated in the tubes of 100nm TiNTs. Molecular dynamics simulation was performed to elucidate the adsorption mechanism. The simulation results confirmed that physical adsorption was the main driving force, including van der Waals force and hydrogen bond between Col-I molecules and TiNTs. The calculated interaction energies indicated that the TiNTs with bigger dimensions had higher interaction energies, thus leading to the higher collagen adsorption.