Synergistic effect of crystalline phase on protein adsorption and cell behaviors on TiO2 nanotubes

Abstract

The objective of this study is to explore the structure-property relationships of TiO 2 nanotubes (TNTs) with different crystalline phases that link to protein adsorption and cell responses. Given the formation of intact rutile nanotubular structures by furnace annealing is challenge, a combination of furnace annealing and flame annealing is employed for the preparation of rutile TNTs. TNTs with pure anatase phase and mixed anatase/rutile phases are obtained by simple furnace annealing of amorphous TNTs. Results show that BSA and FBS adsorptions are greatly enhanced on rutile TNTs, whereas no discernable difference on other crystalline phases. Rutile TNTs also present highest adsorption of fibronectin and collagen which are diminished on anatase and dual anatase-rutile phases. Interestingly, however, there is no significant difference in cell proliferation or differentiation on TNTs with different crystallites. Scrutinization of the surface properties involved in protein adsorption and cell activities, a synergistic effect of surface charge, hydroxyl groups, and roughness is found on protein adsorption which further regulates cell behaviors. Those findings provide a better understanding of the structure-property relationships of titanium-based biomaterials.

Effect of size and crystalline phase of TiO2 nanotubes on cell behaviors: A high throughput study using gradient TiO2 nanotubes

“…6 a, compared the as-prepared TNTs to the annealed TNTs with the same dimension, cell behaviors were similar and there was no significant difference in vinculin distribution or actin cytoskeleton. It explains why the effects of crystalline phases on cell behaviors are not significant through the entire gradient, consistent with our previous study [ 35 ]. A reasonable explanation is that the synergistic effects of different surface properties and competitive protein adsorption diminish the difference between as-prepared TNTs and annealed TNTs.…”

“…3 b). This could be owing to the synergistic effects of surface properties and competitive protein adsorption in serum [ 35 ]. Different properties had different effects on protein adsorption that combined effects of varied properties could be found on protein adsorption, including crystalline phase, surface chemistry, and wettability.…”

“…Some research groups demonstrated that TNTs with the smallest nanotube diameter promoted the highest cell proliferation and/or differentiation [ [25] , [26] , [27] , [28] ] whereas some groups proved controversial results, or even opposite [ [29] , [30] , [31] ]. Some studies indicated that annealed nanotubes could facilitate cell proliferation [ 32 , 33 ] whereas some studies found different results [ 34 , 35 ]. Moreover, the nanotube diameter could range from a few nm to hundreds of nm, which not only provides infinite possibilities but also poses great challenges.…”

Titanium and Protein Adsorption: An Overview of Mechanisms and Effects of Surface Features

“…TiO 2 phase is easily controlled through heat treatment: By increasing the treating temperature, amorphous titania is transformed into anatase at first and then to rutile, at about 600 °C [ 175 ]. The effect of different crystalline phases of titanium on protein adsorption has been investigated largely on TNT substrates [ 126 , 175 , 176 , 177 ]. Native oxide on flat cp-Ti was turned from amorphous to mainly anatase by annealing, showing almost no differences in the adsorption of BSA and FIB [ 126 ].…”

<p>Biomedical Applications of TiO₂ Nanostructures: Recent Advances</p>

“…While crystalline phase of TiO2 NTs has no significant effect on cell proliferation and differentiation. 110 In conclusion, the nanotopography of dental implant surface results in better osseointegration, cell adhesion and blood response of dental implants, which are very important in the success of the implant.…”