Growth of TiO2 Nanotube on Titanium Substrate to Enhance its Biotribological Performance and Biocorrosion Resistance

Abstract

TiO2 nanotubes (NTs) have a great potential in improving the osetointegration of titanium (Ti)-based biomaterials. Much efforts have been made to evaluate the biological performance of the TiO2 nanotube in regulating protein adsorption and cells attachments. As often used in orthopaedic applications, although biotribological performance and biocorrosion are important issues in these applications, few researches have been reported on the biotribological performance of NT layers. This paper reports the preparation of a structure-optimised TiO2 NT (SO-NT) material via a multi-step oxidation strategy, as well as its biotribological and biocorrosion behaviours. In this procedure, an interfacial bonding layer of approximately 120-150 nm was first formed on the titanium substrate, which is then joined to the NT bottoms. The mechanical testing with respect to impact, bending, and biotribological performance have demonstrated the resultant SO-NT layer possess improved mechanical stability compared to conventional NT. The uniform hyperfine interfacial bonding layer with nano-sized grains exhibited a strong bonding to NT layer and Ti substrate. It was observed, the layer not only effectively dissipates external impacts and shear stress but also acts as a good corrosion resistance barrier to prevent the Ti substrate from corrosion. Theoretical models are proposed to analyse and predict the shear performance and corrosion-resistance mechanisms of the resultant material. The obtained results demonstrated that the SO-NT material has great potential in orthopaedic applications

Evolution of anodised titanium for implant applications

“…To date, considering the growth of the nano-thick oxide film ( Figure 8 (c)) in the Ti/TNTs interface ( Figure 8 (b): ox 1 to ox 2 , as observed elsewhere [ 290 , 320 , 334 ]) together with the existence of tribofilm-laminated porous walls on top of the TNTs ( Figure 8 (d)), the fitting model as shown in Figures 8 (e) and 8(f) has been shown to be the most appropriate electronic fitting (lowest accuracy) ever reported for the anodised titanium [ 144 , 286 , 330 , 332 ].…”

“…The production process of anodised titanium via two-step AO is now common practice in order to produce a bio-functionalised and reliable passivation of TiO 2 with higher degrees of mechanical stability [92,93,164,298,320,355,356]. Bartkowiak et al [355] suggested a U-shaped layering of TNTs derived from two-step anodisation produced a highly adherent TNTs to the substrate.…”

“… Formation of interfacial layer in SO-TNTs act like a “barrier”, which prevents the underlying Ti substrate from erosion. [ 320 ] In/ex vivo Example in/ex vivo studies on Anodised Ti Histomorphometry [ 321 ] histologically and quantitatively assesses bone cells, growth, tissue remodeling, bone architecture, and repair both the activity of bone cells and the amount and distribution of bone tissue can be analysed Bone Implant Contact (BIC) Visualisations (qualitative measure) usually assisted with μCT [ 316 ] Routine Histological [ 315 ] stained site shows more cellular detail, but underemphasises the mineralised bone does not permit direct evaluation of BIC or bone neoformation near implant surface upon removal/damage of mineral content Micro-arc anodised RBM Ti dental implants, placed in sheep mandible implanted mandibular site dissected en bloc prior to testing. implantation period: 4 weeks Fixed in formalin, dehydrated with ethanol, cleared with xylol and set in C 5 H 8 O 2 ., then sectioned and glued to plastic slides, polished by silicon carbide, then stained with one part of MacNeal's tetrachrome followed by two parts of toluidine blue.…”

“…The interpretation of findings from real-time or in situ study to detect engineered surface reactions in an implanted environment has been very limited. Most studies have used a combination of electrochemical and tribocorrosion analysis to simulate the in vitro test environment by mimicking the body's fluid reactions on the proposed surface [ 209 , 280 , 287 , 298 , 319 , 320 ]. A surface profilometer has rarely been used in tribocorrosion analysis to calculate how much wear was produced using a tribology test [ 307 ].…”

“…The production process of anodised titanium via two-step AO is now common practice in order to produce a bio-functionalised and reliable passivation of TiO 2 with higher degrees of mechanical stability [ 92 , 93 , 164 , 298 , 320 , 355 , 356 ].…”