Anodized Ti Surface Research Articles

Effect of Biomimetic Deposition on Anodized Titanium Surfaces

Surface energy and hydrophilicity of implant surfaces have been known to play an important role in subsequent cellular responses on the implant surface. The aim of the present study was to evaluate the effects of biomimetic deposition of anodized surfaces on surface wettability, surface energy, and osteoblast responses. Ti discs with 2 different surface topographies (machined and anodized) were immersed in Hanks’ balanced salt solution (HBSS) and modified simulated body fluid (SBF) solution for 2 weeks at physiologic conditions of 37°C, initial pH of 7.4, and p(CO2) of 0.05 atm. Scanning electron microscopic (SEM) observation and energy-dispersive spectroscopic (EDS) microanalysis showed the deposition of calcium phosphate (CaP) onto anodized Ti surfaces immersed in modified SBF. Surface energy, surface wettability, and osteoblast responses, including cell attachment capacity, cell proliferation rate, and cell differentiation level, significantly increased on anodized Ti surfaces immersed in modified SBF. The effects of biomimetic deposition with modified SBF on physiochemical surface characteristics and cell biological responses were greater on anodized surfaces than on machined surfaces. These results indicate that biomimetic deposition with effective SBF may enhance the interaction between anodized Ti surfaces and their biological environment, consequently improving bone healing of dental Ti implants.

Investigations into the molecular-level adhesion characteristics of hydroxyapatite-coated and anodized titanium surfaces using the molecular orbital approach.

It has been established that the adhesion of cells on to the surfaces of orthopaedic implants depends on the ability of the surfaces to accommodate protein molecules. Hydroxyapatite coating and anodizing are the most common methods to make TiAl6V4 implants (Ti) more biocompatible. In this paper Spartan 02, a molecular dynamics software, is used to analyze and predict the bonding characteristics of Extra cellular matrix protein sequence arginine-glycine-aspartic acid (RGD) on a Hyrdoxyapatite (HA) coated Ti and an anodized Ti surface based on the property of its constituent atoms, their polarity (net electrostatic charge, Qr), the energies of the molecular orbital E_HOMO (energy of the highest occupied molecular orbital), and E_LUMO (energy of the lowest unoccupied molecular orbital). The results show favourable criterion for formation of bonding between the HOMO orbital of the HA coated and anodized surfaces and LUMO orbital of the glycine strand from the RGD unit. The mechanism of bonding of individual atoms to form primary calcium oxide compounds is likely only in the case of HA coated surfaces . The surface texture of the anodized Ti with inherent porosities appear more responsible for the adsorption of proteins on to them by mechanical interlocking than the formation of any intermediate calcium oxide compounds.

Fabrication of anodized titanium with immobilization of hyaluronic acid to improve biological performance

Titanium (Ti) is used widely as a dental implant material in clinical dentistry and as an orthopedic implant material. Anodized titanium enhances the biocompatibility of Ti, which is improved further by hyaluronic acid (HA) immobilization on the anodized Ti surface. Plasma treatment of metal surfaces creates functional groups to introduce bioactive materials. This study evaluated a new bioactive functionalized Ti surface produced by immobilizing hyaluronic acid (HA) onto –NH 2 functionalized anodizing Ti surfaces to improve the biological, physical and chemical properties of Ti. A porous microstructure was formed on Ti by anodizing, followed by the introduction of NH 2 groups by plasma polymerization and immobilization of HA onto the –NH 2 functionalized anodizing Ti surfaces. The samples were characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, attenuated total reflection Fourier transfer infrared spectroscopy and atomic force microscope. MC3T3-E1 cells were cultured on each sample and the cell viability was examined using a MTT assay. 0.2–0.5 μm pores (approximately) were formed on the surfaces of titanium and HA was immobilized successfully with a covalent bond. The cell viability tests revealed significantly enhanced viability on the anodized and HA coated anodized metals than on the unanodized metals.

Improving the biocompatibility of titanium surface through formation of a TiO 2 nano-mesh layer

This study was to evaluate the biocompatibility, as determined by corrosion resistance and cell responses, of TiO 2 nano-mesh layer on polished Ti surface. Results showed that a TiO 2 nano-mesh layer was formed on the anodized Ti surface through electrochemical anodization treatment. In comparison to the polished Ti surface, the presence of TiO 2 nano-mesh layer on the anodized Ti surface increased the corrosion potential and decreased the corrosion rate and passive current in simulated body fluid. The nano-mesh layer also caused better cell adhesion and spreading, as well as faster cell proliferation and initial differentiation. Overall, this TiO 2 nano-mesh layer improved the biocompatibility of Ti surface.

The relationship between the nanostructure of titanium surfaces and bacterial attachment

Infection of an orthopedic prosthesis is undesirable and causes a decrease in the success rate of an implant. Reducing the adhesion of a broad range of bacteria could be an attractive means to decrease infection and allow for subsequent appropriate tissue integration with the biomaterial surface. In this in vitro study, nanometer sized topographical features of titanium (Ti) surfaces, which have been previously shown to enhance select protein adsorption and subsequent osteoblast (bone-forming cell) functions, were investigated as a means to also reduce bacteria adhesion. This study examined the adhesion of Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa on conventional Ti, nanorough Ti produced by electron beam evaporation, and nanotubular and nanotextured Ti produced by two different anodization processes. This study found that compared to conventional (nano-smooth) Ti, the nanorough Ti surfaces produced by electron beam evaporation decreased the adherence of all of the aforementioned bacteria the most. The conventional and nanorough Ti surfaces were found to have crystalline TiO 2 while the nanotubular and nanotextured Ti surfaces were found to be amorphous. The surface chemistries were similar for the conventional and nanorough Ti while the anodized Ti surfaces contained fluorine. Therefore, the results of this study in vitro study demonstrated that certain nanometer sized Ti topographies may be useful for reducing bacteria adhesion while promoting bone tissue formation and, thus, should be further studied for improving the efficacy of Ti-based orthopedic implants.

Formation of TiO 2 nano-network on titanium surface increases the human cell growth

Objectives This study was to improve human cell growth on titanium (Ti) used for dental implants through formation of a nano-network surface oxide layer created by an electrochemical anodization treatment. Methods An electrochemical anodization treatment was used to produce a network oxide layer on Ti surface. Surface characterization of the network layer was carried out using thin film X-ray diffractometer and field emission scanning electron microscopy. Human bone marrow mesenchymal stem cells (hMSCs) were made to express green fluorescent protein (GFP) by retroviral transduction. The GFP signal was measured in situ to assess in vitro and in vivo cell growth on Ti surfaces. In vivo experiments on Ti-supported cell growth were carried out on the back skin of nude mice. Alizarin red staining and immunofluorescent staining were used to observe cell differentiation. Results A multilayer TiO 2 nano-network was produced rapidly on Ti surface using a simple electrochemical anodization treatment. The TiO 2 nano-network layer on the anodized Ti surfaces significantly improved in vitro and in vivo hMSC growth, as assessed by measurement of GFP fluorescence, relative to hMSC growth on untreated Ti surface. The TiO 2 nano-network layer on the anodized Ti surfaces can also induce the differentiation of hMSCs after 28-day in vivo test. Significance The formation of TiO 2 nano-network on the Ti surfaces can increase the hMSC growth in vitro and in vivo.

Nano/submicron-scale TiO 2 network on titanium surface for dental implant application

In this study, a fast electrochemical anodization treatment, applying different anodic currents, was used to produce a nano/submicron-scale network oxide layer on Ti metal surface for biomedical implant application. The anodized Ti surface was analyzed using thin film X-ray diffractometer, X-ray photoelectron spectrometer, and field emission scanning electron microscope. The whole blood coagulation and human bone marrow stem cells (hBMSCs) adhesion on the anodized Ti surface were evaluated. Results showed that a nano/submicron-scale TiO 2 network layer with a lateral pore size of 20–160 nm could be rapidly produced on Ti surface through electrochemical anodization treatment. Increasing the applied anodic current led to an increase in pore size of TiO 2 network. The nano/submicron-scale TiO 2 network layer significantly enhanced the whole blood coagulation and hBMSCs adhesion on Ti surface.

Biological responses in osteoblast‐like cell line according to thin layer hydroxyapatite coatings on anodized titanium

Several features of the implant surface, such as roughness, topography and composition play a relevant role in implant integration with bone. This study was conducted in order to determine the effects of various thin layer hydroxyapatite (HA) coatings on anodized Ti surfaces on the biological responses of a human osteoblast-like cell line (MG63). MG63 cells were cultured on 100 nm HA (100 nm HA coating on anodized surface), 500-700 nm HA (500-700 nm HA coating on anodized surface), 1 mum HA (1 mum HA coating on anodized surface) and anodize (non-HA coating on anodized surface) Ti. The morphology of these cells was assessed by scanning electron microscopy (SEM). The cDNAs prepared from the total RNAs of the MG63 were hybridized into a human cDNA microarray (1152 elements). The appearances of the surfaces observed by SEM were different on each of the four dental substrate types. MG63 cells cultured on 100 nm HA, 1 mum HA and anodize exhibited cell-matrix interactions. It was 500-700 nm HA surface showing cell-cell interaction. In the expression of genes involved in osseointegration, several genes, including bone morphogenetic protein 2, latent transforming growth factor beta binding protein 1, catenin (cadherin-associated protein), integrin, PDGFRB and GDF-1 growth differentiation factor 1 were up-regulated on the different surfaces. Several genes, including fibroblast growth factor receptor 3, fibroblast growth factor 12 and CD4 were down-regulated on the different surfaces. The attachment and expression of key osteogenic regulatory genes were enhanced by the surface morphology of the dental materials used.

Preparation and Characterization of Anodized Titanium Surfaces and Their Effect on Osteoblast Responses

In this study, titanium (Ti) surface was modified by anodizing with a mixture of beta-glycerophosphate sodium and calcium (Ca) acetate, and the anodized surfaces were characterized by scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. In vitro osteoblast response to anodized oxide was also evaluated. The anodic oxide produced was observed to have interconnected pores (0.5-2 microm in diameter) and intermediate roughness (0.60-1.00 microm). In addition, anodic oxide was observed to have amorphous and anatase oxide. Calcium and phosphorus ions were deposited on the Ti oxide during anodization. Osteoblast differentiation, as indicated by alkaline phosphatase production, was enhanced on anodized surfaces. It was thus concluded from this study that Ca phosphate can be deposited on Ti surfaces by anodization. It was also concluded that the phenotypic expression of osteoblast was enhanced by the presence of Ca phosphate and higher roughness on anodized Ti surfaces.

Effect of hydrothermally treated anodic oxide films on osteoblast attachment and proliferation

In this study, the effect of anodization following hydrothermal treatments on osteoblast cell attachment and proliferation were evaluated. The anodic oxide films produced in this study was observed to exhibit overlapping microporous structures with microprojections. In addition, the anodic oxide surfaces were significantly rougher in comparison to control untreated titanium (Ti) surfaces. Following hydrothermal treatments for 2 and 4 h, hydroxyapatite (HA) crystals were observed on anodic surfaces. Using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, no significant difference in the biocompatibility of the treated and untreated Ti surfaces was observed. However, scanning electron micrographs indicated rounded osteoblast cells on control and anodized Ti surfaces, with numerous microvilli after 6 h. In contract, cells cultured on hydrothermally treated surfaces after 6 h incubation were observed to exhibit polygonal shape, flattened, and fully spread. In addition, more cells were observed on Ti surfaces that were hydrothermally treated for 4 h as compared to Ti surfaces that were hydrothermally treated for 2 h. After culturing the cells for 24 h and 4 days, no significant difference was observed for cells cultured on all surfaces. It was concluded from this study that hydrothermally treated surfaces exhibited an effect on early osteoblast attachment.

Electrochemical corrosion analyses and characterization of surface-modified titanium

Titanium (ASTM F76) samples received three different surface treatments after which the resulting oxides were characterized and the corrosion behavior was evaluated. No differences in the corrosion potential ( E corr) were observed for the non-passivated and passivated Ti samples. However, the anodized Ti samples exhibited a significantly more noble E corr. At potentials higher than E corr, significant differences in current densities were observed for all three different Ti surfaces, with lower current densities observed for anodized Ti samples as compared to the non-passivated and passivated Ti samples. X-ray photoelectron spectroscopy indicated predominantly TiO 2 on all Ti surfaces, with a higher concentration of carboxyl species for the anodized Ti surfaces as compared to the non-passivated Ti surfaces. Auger electron spectroscopy revealed a 10-fold thicker oxide layer for anodized Ti surfaces as compared to non-passivated and passivated Ti surfaces.