Pure Titanium Surface Research Articles

Tailoring the synthesis of tantalum-based thin films for biomedical application: Characterization and biological response

The aim of this study was to tailor the deposition parameters of magnetron sputtering to synthetize tantalum oxide (TaxOy) films onto commercially pure titanium (cpTi) surface. The structural and optical properties, morphology, roughness, elemental chemical composition and surface energy were assessed. The impact of TaxOy films on initial Streptococcus sanguinis adhesion was investigated. The morphology and spreading of pre-osteoblastic (MC3T3-E1) cells on a crystalline tantalum oxide film were evaluated. TaxOy films with estimated thickness of 600 nm and different structures (amorphous or crystalline) were produced depending on the various oxygen flow rates and parameters used. X-ray diffraction analysis revealed that the 8 O2 sccm (600 °C/400 W) group showed crystallization corresponding to the β-Ta2O5 phase. Optical analysis showed that the 4 O2 sccm (200 °C 300 W) to 8 O2 sccm (600 °C 300 W) groups and 10 O2 sccm (200 °C 300 W) group presented regular and large-amplitude interference oscillations, suggesting high optical homogeneity of the films. The crystalline β-Ta2O5 coating showed higher roughness and surface energy values than the other groups (P < .05) and was biocompatible. Compared with cpTi, the amorphous and crystalline tantalum oxide films did not increase bacterial adhesion (P > .05). By tailoring the deposition parameters, we synthetized a crystalline β-Ta2O5 coating that improved titanium surface properties and positively affected cell spreading and morphology, making it a promising surface treatment for titanium-based implants.

Morphology and Wear Resistance of Composite Coatings Formed on a TA2 Substrate Using Hot-Dip Aluminising and Micro-Arc Oxidation Technologies.

Aluminium layers were coated onto the surface of pure titanium using hot-dip aluminising technology, and then the aluminium layers were in situ oxidised to form oxide ceramic coatings, using the micro-arc oxidation (MAO) technique. The microstructure and composition distribution of the hot-dip aluminium coatings and ceramic layers were studied by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The phase structure of the MAO layers was studied using X-ray diffraction. The surface composition of the MAO layer was studied by X-ray photoelectron spectroscopy. The wear resistance of the pure titanium substrate and the ceramic layers coated on its surface were evaluated by using the ball-on-disc wear method. Therefore, aluminising coatings, which consist of a diffusion layer and a pure aluminium layer, could be formed on pure titanium substrates using the hot-dip aluminising method. The MAO method enabled the in-situ oxidation of hot-dip pure aluminium layers, which subsequently led to the formation of ceramic layers. Moreover, the wear resistance values of the ceramic layers were significantly higher than that of the pure titanium substrate.

Preparation of icariin/TiO2 nanotube composite coating on pure titanium surface and analysis of early drug release.

The surface modification of pure titanium and the improvement of the early osseointegration of titanium implants are research hotspots currently. This study aimed to load icariin onto the surface of TiO2 nanotube to form the composite coating, and to study the amount of loaded drug and the importance of early release. The TiO2 nanotube was formed on the surface of smooth pure titanium via anodic oxidation, and both smooth pure titanium and TiO2 nanotube were characterized using the scanning electron microscope, atomic force microscope and contact angle apparatus. Moreover, icariin was loaded onto the surface of pure titanium and TiO2 nanotube using the soaking method. The amount of early drug release in both types of materials was determined via high-performance liquid chromatography. The amount of loaded drug was calculated, and the curves of cumulative release amount and cumulative release percentage were plotted. The TiO2 nanotube had a diameter of 80 nm with greater roughness than that of pure titanium (p<0.05) and smaller contact angle than that of pure titanium (p<0.05). The cumulative drug release amount in the first 14 d and the curve of cumulative drug release in the first 4 h in icariin/TiO2 nanotube group were significantly larger and higher than those in the icariin/pure titanium group. The curve of cumulative drug release percentage was flatter and the release time was longer in icariin/TiO2 nanotube group than those in the icariin/pure titanium group. Our results indicate that the icariin/TiO2 nanotube composite coating can provide a higher drug loading amount with a sustained-release effect.

Electrochemical Properties of Commercially Pure Ti with TiB/TiB2 Coatings in Hanks’ Balanced Salt Solution

In this study, in order to evaluate the electrochemical performance of different titanium boride coatings created on the commercially pure titanium (CP-Ti), distinct electrochemical assays in Hanks’ balanced salt solution at 37 °C were conducted using pack cementation method. The results showed that the boriding at 900 and 1000 °C for 3 h creates the TiB whiskers and TiB whiskers/TiB2 dense layer on the top of the commercially pure titanium surface, respectively. It was also found that not only borides coating had good adhesion on the substrate, but also that improved the titanium hardness more than five times. Polarization plots clarified the passive behavior of borided specimens. Impedance spectroscopy tests indicated the acceptable corrosion behavior of the borided specimens in Hanks’ balanced salt solution. Mott–Schottky measurements indicated that the passive layers formed on the commercially pure titanium and the borided specimens had doped n-type semiconductor properties. Mott–Schottky measurements displayed that the donor density of the passive layers decreased with the rising time as well. Finally, because of better surface conditions to make a less defective and more protective passive layer, the borided specimen at 900 °C in comparison with the borided specimen at 1000 °C was shown to be the more suitable choice for bioimplant applications.

Surface morphology and surface properties of Ti and TiZr implant materials

Objective: To investigate the effects of hydrophilic treatment on the surface morphology and surface properties of pure titanium and titanium-zirconium alloy implants, and to provide reference for the studies of implant surface modification. Methods: The pure titanium group, the hydrophilic pure titanium group, the titanium zirconium alloy group and the hydrophilic titanium-zirconium alloy group were prepared by sandblasting and acid-etching or hydrophilic sandblasting and acid-etching, (11 specimens in each group). The surface morphology and surface properties of four types of titanium specimens were analyzed by surface contact angle meter, scanning electron microscope (SEM), optical profilometer, atomic force microscope (AFM) and Raman spectrometer. Results: The surface contact angles of hydrophilic pure titanium and hydrophilic titanium-zirconium alloy were 1.6°±0.3° and 1.5°±0.2°, and the surface contact angles of pure titanium and titanium-zirconium alloy were 101.4°±4.6° and 96.2°±3.0°, respectively. SEM showed that the nano-protrusions on the surface of pure titanium and titanium-zirconium alloys were less or even absent, while the nano-protrusions on the surface of hydrophilic pure titanium and hydrophilic titanium-zirconium alloys were relatively more; the nano-protrusions on the surface of hydrophilic pure titanium surface were small and dense relatively, but the nano-protrusions of the hydrophilic titanium-zirconium alloy had large diameters and were dispersed relatively. The optical profiler and AFM showed that the surface roughness of hydrophilic pure titanium and hydrophilic titanium-zirconium alloy was significantly higher than that of pure titanium and titanium-zirconium alloy (P<0.05). Raman spectroscopy showed that only the amorphous TiO(2) was present on the surface of the pure titanium group, while the rutile TiO(2) characteristic peak was observed in the other three groups, but the lateral inhomogeneity was observed. After Raman shift 610 cm(-1), the Raman spectra of four groups were similar. Conclusions: Hydrophilic sandblasting and acid-etching treatment can improve the surface hydrophilicity and surface roughness of pure titanium and titanium zirconium alloy, and improve the surface properties of pure titanium and titanium zirconium alloy implants.

Effects of ECAP on the Formation and Tribological Properties of Thermal Oxidation Layers on a Pure Titanium Surface

In this paper, thermal oxidation was used to prepare an oxide layer on a pure titanium surface using the equal-channel angular pressing (ECAP) treatment. Transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction and Raman spectrometry were used for morphology and structure characterization and investigation of the oxidation kinetics during the oxidation process. The results showed that the major phase of the oxide layer was rutile-type TiO2. The presence of voids in the oxide layer decreased with increasing temperature. The grain size of the TiO2 obtained on the ECAP-treated Ti surface was smaller than that on the as-received titanium. The ECAP treatment promoted the formation of the oxide layer; the activation energy (Q) for the oxidation reaction with ECAP treatment was 81.03 kJ mol−1 in the range of 650 °C to 850 °C, which was 26.3% lower than that of the as-received titanium. The hardness values of the oxide layers on the as-received titanium and ECAP-treated Ti were 705.8 HV and 805.1 HV, respectively. The friction coefficient of the oxide layer on the ECAP-treated Ti was lower than that on the as-received titanium. The wear rates of the oxide layers on the ECAP-treated Ti and as-received titanium were 4.66 × 10−8 mm3 N−1 m−1 and 6.28 × 10−8 mm3 N−1 m−1, respectively.

Microstructure and mechanical properties of TiC-Fe surface gradient coating on a pure titanium substrate prepared in situ

A TiC-Fe surface gradient coating was prepared on the surface of pure titanium by a simple two-step heat-treatment process (1150 °C × 5 min + 1000 °C × 10 h). The phase composition, microstructure, nanoindentation hardness, elastic modulus, fracture toughness, and adhesion strength of the TiC-Fe surface gradient coating were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), nanoindentation testing, and scratch testing. The results reveal that the TiC-Fe surface gradient coating was composed of dense TiC grains and a small amount of α-Fe. The TiC-Fe surface gradient coating was divided into three zones according to the variation in the volume fractions of TiC particulate and α-Fe phase. These zones were labeled as follows: a columnar TiC zone (I zone), a large particle TiC zone (II zone) and a large bulk TiC zone (III zone). The formation process and mechanism of the TiC-Fe surface gradient coating include the nucleation growth of TiC grains, followed by diffusion and in situ reactions between titanium and carbon. The nanoindentation hardness and elastic modulus for cross section of the TiC-Fe surface gradient coating ranged from 19.1 to 31.7 GPa and from 368.1 to 464.3 GPa, respectively. The fracture toughness values of I zone, II zone and III zone are 3.5, 1.6 and 3.1 MPa m1/2, respectively, and these values largely depend on composition and microstructure. Investigations of crack surface morphologies indicate that radial cracks at the corners of the indentation originate from the crossing of slip bands and that the toughening mechanism was mainly crack deflection and bridging. In addition, the scratch testing indicated that the coating exhibited excellent coating/substrate adhesion strength.

Cytotoxicity and antibacterial efficacy of silver deposited onto titanium plates by low-energy ion implantation

Abstract

Evaluation of Surface Characteristics and Hemocompatibility on the Oxygen Plasma-Modified Biomedical Titanium

Oxygen plasma with different treatment powers and durations was utilized to modify the biomedical pure titanium (Ti) surface in the present study. The superficial, microstructural and biological properties of the plasma-oxidized samples were investigated using the electron microscopy, X-ray photoemission spectroscopy, grazing incidence X-ray diffractometer, contact angle goniometer and blood clotting time assay. During different treatment powers and durations, the island-like nanostructural rutile-TiO2 layer and dimple-like nanostructural rutile-TiO2 layer were generated on the surfaces of the plasma-oxidized samples, respectively. It was also found that the plasma-oxidized sample with a rough oxide layer resulted in the formation of a higher wettability. Moreover, the blood clotting time assay indicated that the plasma-oxidized samples exhibited the adhesion behaviors of red blood cells. As the Ti surface underwent plasma oxidation at 280 W for 30 min, it not only generates a rough nanostructural rutile-TiO2 layer, but also presents an excellent hemocompatibility. Therefore, these findings demonstrate that oxygen plasma modification is a potential approach to promote the hemocompatibility of biomedical pure Ti surface.

Surface functionalization of TiO2 nanotubes with minocycline and its in vitro biological effects on Schwann cells

BackgroundMinocycline has been widely used in central nervous system disease. However, the effect of minocycline on the repairing of nerve fibers around dental implants had not been previously investigated. The aim of the present study was to evaluate the possibility of using minocycline for the repairing of nerve fibers around dental implants by investigating the effect of minocycline on the proliferation of Schwann cells and secretion of neurotrophic factors nerve growth factor and glial cell line-derived neurotrophic factor in vitro.MethodsTiO2 nanotubes were fabricated on the surface of pure titanium via anodization at the voltage of 20, 30, 40 and 50 V. The nanotubes structure were characterized by scanning electron microscopy and examined with an optical contact angle. Then drug loading capability and release behavior were detected in vitro. The TiO2 nanotubes loaded with different concentration of minocycline were used to produce conditioned media with which to treat the Schwann cells. A cell counting kit-8 assay and cell viability were both selected to study the proliferative effect of the specimens on Schwann cell. Reverse transcription-quantitative PCR and western blot analyses were used to detect the related gene/protein expression of Schwann cells.ResultsThe results showed that the diameter of TiO2 nanotubes at different voltage varied from 100 to 200 nm. The results of optical contact angle and releasing profile showed the nanotubes fabricated at the voltage of 30 V met the needs of the carrier of minocycline. In addition, the TiO2 nanotubes loaded with the concentration of 20 μg/mL minocycline increased Schwann cells proliferation and secretion of neurotrophic factors in vitro.ConclusionsThe results suggested that the surface functionalization of TiO2 nanotubes with minocycline was a promising candidate biomaterial for the peripheral nerve regeneration around dental implants and has potential to be applied in improving the osseoperception of dental implant.

Multi-Walled Carbon Nanotube Coating on Alkali Treated TiO2 Nanotubes Surface for Improvement of Biocompatibility

The aim of this study is to enhance the bioactivity of pure titanium using multiple surface treatments for the application of the implant. To form the biofunctional multilayer coating on pure titanium, anodization was conducted to make titanium dioxide nanotubes, then multi-walled carbon nanotubes were coated using a dipping method after an alkali treatment. The surface characteristics at each step were analyzed using a field emission scanning electron microscope and X-ray diffractometer. The effect of the multilayer coating on the biocompatibility was identified using immersion and cytotoxicity tests. Better hydroxyapatite formation was observed on the surface of multilayer-coated pure titanium compared to non-treated pure titanium after immersion in the simulated body fluid. Improvement of biocompatibility by multiple surface treatments was identified through various cytotoxicity tests using osteoblast cells.

Electrochemical behavior of titanium exposed to a biofilm supplemented with different sucrose concentrations

Statement of problemBiofilms can reduce the corrosion resistance of titanium because of the bacterial metabolism of fermentable carbohydrates, including sucrose. However, studies evaluating whether biofilms exposed to higher sucrose concentrations can affect the electrochemical behavior of titanium are lacking. PurposeThe purpose of this in vitro study was to test the electrochemical behavior of titanium previously exposed to biofilm supplemented with different sucrose concentrations. Material and methodsStreptococcus mutans UA159 biofilms were formed on commercially pure titanium (cpTi) surfaces and supplemented constantly with different sucrose concentrations (0%, 1%, 10%, and 40%) for 7 days (experimental groups) (n=12 per group). CpTi disks without biofilm were used as a control (n=12). The standard electrochemical tests open-circuit potential, electrochemical impedance spectroscopy, and potentiodynamic curve were performed. Data were submitted to ANOVA and the Tukey honestly significant difference (HSD) tests (α=.05). ResultsThe biofilm exposed to sucrose had an increased biofilm dry weight (P<.05). The polysaccharide amount and the pH drop were higher in the groups exposed to sucrose (P<.05). No difference was noted between the control and experimental groups for the electrochemical properties of cpTi (P>.05). ConclusionsBiofilms exposed to greater carbohydrate concentration did not alter the corrosive behavior of titanium.

Pretreatment effect of the pure titanium surface on hybrid coating adhesion based on tetraethoxysilane and methyltriethoxysilane

Hybrid coatings based on silicon alkoxide precursors are one of the options for coating metal surface biomaterials such as pure titanium (Ti). However, the nature and the metal surface preparation, before the coating application, are of fundamental importance for perfecting the coating/surface adhesion. In this study, three different pretreatments were used for the Ti surface: Kroll, Piranha and NaOH. After the pretreatment, the coating was applied by the dip-coating process, using the sol–gel method from the silicon alkoxide precursors, tetraethoxysilane and methyltriethoxysilane. The results of thermogravimetric analysis showed that the tested coatings had excellent thermal stability. The pretreatment with NaOH solution increased the surface roughness of the Ti, thus modifying its surface energy and increasing its wettability. Field emission scanning electron microscopy showed a homogeneous coating with good adhesion of the hybrid coating to the Ti surface, and higher layer thickness on the surface treated with NaOH. In addition, its electrochemical performance was better than the surfaces pretreated with acids.

Plasma surface tantalum alloying on titanium and its corrosion behavior in sulfuric acid and hydrochloric acid

An anti-corrosion Ti-Ta alloy coating was prepared on pure titanium surface by double glow plasma surface alloying technology. Electrochemical corrosion test was applied to test the anti-corrosion property of Ti-Ta alloy layer. The microstructure and the phase composition of Ti-Ta alloy coating were detected before and after corrosion process by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The results showed that the Ta-Ti alloy layer has a thickness of about 13–15 μm, which is very dense without obvious defects such as pores or cracks. The alloy layer is composed mainly of β-Ta and α-Ti. The Ta alloy layer improves the anti-corrosion property of pure titanium. A denser and more durable TiO2 formed on the surface Ta-Ti alloy layer after immersing in strong corrosive media may account for the excellent corrosion resistant.

Dopamine self-polymerized along with hydroxyapatite onto the preactivated titanium percutaneous implants surface to promote human gingival fibroblast behavior and antimicrobial activity for biological sealing.

The clinical success of dental implants requires not only the optimum osseointegration but also the integration of implant surface with soft tissues to form biological sealing. In this study, alkali-heat treatment was applied to modify the pure titanium surface constructing a unique micro-and nano-structure. Then, poly(dopamine), along and with the additional incorporation of hydroxyapatite and carboxymethyl chitosan have been successfully infiltrated into the preactivated Ti surface during dopamine self-polymerization proceeding. Here, the effects of poly(dopamine)-modified surface coating on the biological behaviors of human gingival fibroblasts (HGFs) and oral pathogens have been systematically studied, which was critical for the early peri-implant soft tissue integration. The results showed that the poly(dopamine)-modified alkali-heat-titanium surface was a superior substrate for human gingival fibroblast adhesion, spread and proliferation. Moreover, further enhancements on cytoskeleton organization, collagen secretion and fibronectin adsorption were generally observed through the additional incorporation of hydroxyapatite. The addition of carboxymethyl chitosan exerted a positive modulation effect on antibacterial activity. Overall, our study demonstrated that combined superior soft tissue integration and antibacterial activity can be achieved by using poly(dopamine)-modified titanium implant, which has great potential in the optimal design of dental implant.

33. Evaluation and comparison of surface roughness levels, surface wettability, and surface configuration of commercially pure titanium surface

33. Evaluation and comparison of surface roughness levels, surface wettability, and surface configuration of commercially pure titanium surface

Micro-Arc Oxidation Enhances the Blood Compatibility of Ultrafine-Grained Pure Titanium.

Ultrafine-grained pure titanium prepared by equal-channel angular pressing has favorable mechanical performance and does not contain alloy elements that are toxic to the human body. It has potential clinical value in applications such as cardiac valve prostheses, vascular stents, and hip prostheses. To overcome the material’s inherent thrombogenicity, surface-coating modification is a crucial pathway to enhancing blood compatibility. An electrolyte solution of sodium silicate + sodium polyphosphate + calcium acetate and the micro-arc oxidation (MAO) technique were employed for in situ oxidation of an ultrafine-grained pure titanium surface. A porous coating with anatase- and rutile-phase TiO2 was generated and wettability and blood compatibility were examined. The results showed that, in comparison with ultrafine-grained pure titanium substrate, the MAO coating had a rougher surface, smaller contact angles for distilled water and higher surface energy. MAO modification effectively reduced the hemolysis rate; extended the dynamic coagulation time, prothrombin time (PT), and activated partial thromboplastin time (APTT); reduced the amount of platelet adhesion and the degree of deformation; and enhanced blood compatibility. In particular, the sample with an oxidation time of 9 min possessed the highest surface energy, largest PT and APTT values, smallest hemolysis rate, less platelet adhesion, a lesser degree of deformation, and more favorable blood compatibility. The MAO method can significantly enhance the blood compatibility of ultrafine-grained pure titanium, increasing its potential for practical applications.

Pretreatment Influence on Titanium Surface Properties After Gas Nitriding

Influence of an initial mechanical treatment (grinding, polishing) on geometry and physical–mechanical parameters of a commercially pure titanium (Grade 2) surface after thermodiffusive saturation by nitrogen was studied. Microstructure analysis has shown that mechanism of formation and growth of a nitride film depends on the initial mechanical treatment. Nitriding under temperature of 750 °C does not influence practically the quality of ground surfaces and decreases it on one class for polished one. For higher saturation temperatures, surface quality has little dependence from the initial treatment. The best set of geometry and physical–mechanical characteristics belongs to the surface, which was initially polished and nitrided subsequently under 750 °C temperature, which provides its high wear resistance.

Three-dimensional porous graphene nanosheets synthesized on the titanium surface for osteogenic differentiation of rat bone mesenchymal stem cells

Currently, graphene and its derivatives, used for surface modification of orthopedic and dental implants, are mainly in the form of two-dimensional planar structure. There is little information of three dimensional porous graphene nanosheets used as coating materials of titanium and its alloys. In the present study, three dimensional porous graphene nanosheets were first synthesized on the pure titanium surface. The physicochemical properties and osteogenic activity of the three dimensional porous graphene nanosheets-modified titanium (rGO@Ti) were systematically investigated. The results suggested that rGO@Ti showed super hydrophilicity, rough surface and excellent biocompatibility, and could enhance alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization and collagen secretion of rat bone mesenchymal stem cells (rBMSCs). Meanwhile, the expressions of osteogenesis related genes containing ALP, bone morphogenic protein-2 (BMP-2), osteocalcin (OCN), and osteopontin (OPN) on rGO@Ti were improved. The osteogenic differentiation of rBMSCs on rGO@Ti may be ascribed to both its superior protein adsorption ability and physical stimulation induced by the unique structure of three dimensional porous graphene nanosheets.

Microstructure, Growth Kinetics and Some Mechanical Properties of Boride Layers Produced on Pure Titanium by Molten-Salt Boriding

To modify the surface properties of pure titanium, boride layers had been fabricated by the boron molten-salt diffusion on pure titanium surfaces in the temperature range of 900-1100 °C for 5- to 30-h treatments. The results demonstrated that the boride layers were mainly composed of TiB whiskers and TiB2 layers without the rutile titanium oxide TiO2. Two diffusion models were introduced to model the growth kinetics of boride layers. The parabolic growth constants and the boron diffusion coefficients were obtained. The boron activation energies for TiB2 and TiB were 225.617 and 165.266 kJ mol−1, respectively. The surface microhardness of the borided titanium decreased with the increase in distance from the surface. The results of wear tests indicated that the wear properties had been improved significantly compared to the pure titanium under dry sliding conditions.