Improved osseointegration of 3D printed Ti-6Al-4V implant with a hierarchical micro/nano surface topography: An in vitro and in vivo study

Surface morphology of titanium (Ti) implants plays an important role in regulating cell behaviors at the interface. The purpose of our study was to investigate the effect of surface structures from microscale to nanoscale on the proliferation and differentiation of precursor osteoblasts. Sandblasting and acid etching and anodic oxidation were used to fabricate the micro-structure and nano-structure on Ti surface. Physical properties including surface topography, roughness and wettability were measured by scanning electron microscopy, laser scanning microscopy and contact angle goniometry, respectively. The bioactivity and cytocompatibility of different surface morphology were investigated in vitro. The results showed that the hierarchical micro-/nano-structured surface composed of micro-valleys and self-assembly nanotubes was successfully constructed on the substrate of Ti. The hydrophilicity of the micro-/nano-structured surface was significantly heightened in comparison with the polished surface, micro-structured surface and nano-structured surface. Moreover, a compact layer of hydroxyapatite was observed on the micro-/nano-structured surface after immersing in simulated body fluid for 14 days. Higher proliferation rate and alkaline phosphatases activity as well as enhanced biomineralization were also verified on the hierarchically structured surface. All results indicated that the integration of multiscale structures of micro-valleys and nanotubes can provide a better surrounding microenvironment to improve cell sensitivities and promote the cell proliferation and differentiation.

Morphologically modified surface with hierarchical micro-/nano-structures for enhanced bioactivity of titanium implants

Antibacterial properties of laser surface-textured TiO2/ZnO ceramic coatings

Magnesium and its alloys have been introduced as innovative orthopedic implants due to their potential in serving lightweight, bio-active, degradable, and biocompatible properties. Mg and its alloys corrode rapidly in a biological environment and result in losing mechanical properties. However, to enhance corrosion resistance and mechanical properties, Mg alloy was plasma-sprayed with pure hydroxyapatite (HA) and HA reinforced Zinc Oxide (ZnO) powder at three levels (4, 8, and 12 wt%). Surface parameters such as microhardness, surface roughness, and wettability were examined. The electrochemical technique was used to study the corrosion behavior in Ringer's solution. The outcomes confirmed that with the rise in ZnO content in pure HA coatings, the surface properties as well as the corrosion resistance improved significantly. The contact angle of substrates under examination exhibits hydrophilic nature. Collectively, the findings of this study signify HA/ZnO reinforced coatings are a promising approach to improve surface properties and corrosion behavior of Mg alloys for future bone implant applications.

Investigation of surface properties and corrosion behavior of plasma sprayed HA/ZnO coatings prepared on AZ31 Mg alloy

Among the several strategies aimed at polymeric coatings deposition on titanium (Ti) and its alloys, metals commonly used in orthopaedic and orthodontic prosthesis, electrochemical approaches have gained growing interest, thanks to their high versatility. In this review, we will present two main electrochemical procedures to obtain stable, low cost and reliable polymeric coatings: electrochemical polymerization and electrophoretic deposition. Distinction should be made between bioinert films—having mainly the purpose of hindering corrosive processes of the underlying metal—and bioactive films—capable of improving biological compatibility, avoiding inflammation or implant-associated infection processes, and so forth. However, very often, these two objectives have been pursued and achieved contemporaneously. Indeed, the ideal coating is a system in which anti-corrosion, anti-infection and osseointegration can be obtained simultaneously. The ultimate goal of all these coatings is the better control of properties and processes occurring at the titanium interface, with a special emphasis on the cell-coating interactions. Finally, advantages and drawbacks of these electrochemical strategies have been highlighted in the concluding remarks.

https://www.mdpi.com/2079-6412/9/4/268/pdf

Electrochemical Strategies for Titanium Implant Polymeric Coatings: The Why and How

Surface chemical composition and topography are two key factors in the biological performance of implants The aim of this work is to deposit ZnO/TiO2 composite coatings on the surface of titanium substrates by plasma spraying technique The effects of the amount of ZnO doping on the microstructure, surface roughness, corrosion resistance, and biological performance of the TiO2 coatings were investigated The results indicated that the phase composition of the as-sprayed TiO2 coating was mainly rutile Addition of 10% ZnO into TiO2 coating led to a slight shift of the diffraction peaks to lower angle Anatase phase and Zn2TiO4 were formed in 20%ZnO/TiO2 and 30%ZnO/TiO2 coatings, respectively Doping with ZnO changed the topography of the TiO2 coatings, which may be beneficial to enhance their biological performance All coatings exhibited microsized surface roughness, and the corrosion resistance of ZnO/TiO2 coatings was improved compared with pure TiO2 coating The ZnO/TiO2 coatings could induce apatite formation on their surface and inhibit growth of Staphylococcus aureus, but these effects were dose dependent The 20%ZnO/TiO2 coating showed better biological performance than the other coatings, suggesting potential application for bone implants

Chao Peng

Papers

Plasma-Sprayed ZnO/TiO 2 Coatings with Enhanced Biological Performance