A Simple Cerium Coating Strategy for Titanium Oxide Nanotubes’ Bioactivity Enhancement

Abstract

Despite the well-known favorable chemical and mechanical properties of titanium-based materials for orthopedic and dental applications, poor osseointegration of the implants, bacteria adhesion, and excessive inflammatory response from the host remain major problems to be solved. Here, the antioxidant and anti-inflammatory enzyme-like abilities of ceria (CeOx) were coupled to the advantageous features of titanium nanotubes (TiNTs). Cost-effective and fast methods, such as electrochemical anodization and drop casting, were used to build active surfaces with enhanced bioactivity. Surface composition, electrochemical response, and in vitro ability to induce hydroxyapatite (HA) precipitation were evaluated. The amount of cerium in the coating did not significantly affect wettability, yet a growing ability to induce early HA precipitation from simulated body fluid (SBF) was observed as the oxide content at the surface increased. The presence of 4%wt CeOx was also able to stimulate rapid HA maturation in a (poorly) crystalline form, indicating an interesting potential to induce rapid in vivo osseointegration process.

Analytical Techniques for the Characterization of Bioactive Coatings for Orthopaedic Implants

“…In addition, XPS was used to determine the Ca/P, O/P, and O/Ca ratios for all samples after their immersion in SBF, confirming the formation of HA [ 68 ]. Using XPS, insights into the chemical interactions during the formation of the coating can be gained, which is crucial for understanding the final performance of the coating [ 69 , 70 , 71 ]. De Santis et al [ 69 ] used XPS to analyze Ti implant samples with TNT-Ce n (n = 1, 3, 6, 9, and 12, based on the number of depositions) coatings.…”

“…Using XPS, insights into the chemical interactions during the formation of the coating can be gained, which is crucial for understanding the final performance of the coating [ 69 , 70 , 71 ]. De Santis et al [ 69 ] used XPS to analyze Ti implant samples with TNT-Ce n (n = 1, 3, 6, 9, and 12, based on the number of depositions) coatings. It was reported that Ti was fully oxidized to Ti 4+ due to the pure TNTs employed.…”

“…In the characterization of bioactive coatings, FTIR/ATR-FTIR can be used to provide information regarding the chemical composition of such coatings and the bonding that occurs during deposition, whereas in multilayer coatings the number of bilayers can be assessed according to the increased absorbance intensity [ 67 , 69 , 82 , 83 , 84 ]. Moreover, this technique can provide information regarding bioactivity.…”

Nanostructured Ceria: Biomolecular Templates and (Bio)applications

“…Ceria has been studied as an additive for well-known materials used in medical implants in virtue of its antioxidant and anti-inflammatory properties and to favor the direct osseointegration at the biointerface. This concept was applied to titania alloys [ 181 ], and nanotubes, and an increased level of early hydroxyapatite precipitation was noted from simulated body fluid [ 182 ]. Furthermore, ceria-stabilized zirconia has been proposed as a promising biomedical implant material.…”

Improvement of Corrosion Resistance of Stainless Steel Welded Joint Using a Nanostructured Oxide Layer

“…Results show that the anodization process coupled with the heat treatment provides significant corrosion protection to the SS and the welds. Furthermore, the proposed methodology has distinct advantages of being simple, safe, low-cost, and versatile, making it highly promising in numerous fields [33][34][35].…”