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Zn-containing TiO 2 -based coatings with Na, Ca, Si, and K additives were obtained by plasma electrolytic oxidation (PEO) of Ti in order to achieve an effective and broad bactericidal protection without compromising biocompatibility. A protocol has been developed for cleaning the coating surface from electrolyte residues, ensuring the preservation of the microstructure and composition of the surface layer. Using high-resolution transmission electron microscopy, three characteristic microstructural zones in the PEO-Zn coating are well documented: zone 1 with a TiO 2 -based nanocrystalline structure, zone 2 with an amorphous structure, and zone 3 around pores with an amorphous-nanocrystalline structure. The excellent cytocompatibility of PEO-Zn samples was confirmed by three different methods: monitoring the proliferation of MC3T3-E1 cells, assessing the viability of sheep osteoblast cells using calcein-AM staining and fluorescence microscopy, and incubation with spheroids based on primary osteoblast cells and mouse embryonic fibroblast NIH3T3 cells. The PEO-Zn coatings absorb >60% of the incident light over the UV and Vis-NIR spectral ranges. After 24 h, the PEO-Zn coatings completely inactivate four types of strains: Gram-positive Staphylococcus aureus CSA154 and ATCC29213 and Gram-negative Escherichia coli K261 and U20, and also prevent E. coli U20 and K261 biofilm formation. The superior antibacterial activity is associated with the synergistic effect of Zn 2+ ions in safe concentration and reactive oxygen species (ROS) generated in response to either UV irradiation or soft short-term X-ray irradiation. The X-ray irradiation-induced ROS formation by a PEO coating is reported for the first time. The enhanced bactericidal activity after X-ray irradiation compared to UV illumination is attributed to the more intense ROS generation in the first few hours. The results obtained significantly expand the possibilities of using PEO coatings on the surfaces of titanium implants.

Surface-modified commercially pure titanium (Cp-Ti) with zirconium (Zr)-based thin film metallic glasses (Zr-TFMGs) and ZrO 2 thin films were surgically implanted into the tibiae of rats; the bone formation was analyzed to examine the performance of the coatings as a biomaterial. Zr-TFMGs and ZrO 2 thin films were coated on Cp-Ti substrates to monitor the control of assimilation in vitro and in vivo. The microstructural and elemental analyses were carried out for the as deposited thin films by x-ray diffraction (XRD), transmission electron microscopy and x-ray photoelectron spectroscopy. TFMG- and ZrO 2 -coated Ti specimens were immersed in simulated body fluid (SBF) for a period of 21 days to evaluate the calcium phosphate precipitation in vitro. XRD, x-ray photoelectron spectroscopy and scanning electron microscopy/energy dispersive x-ray spectroscopy were used to quantify the mineralization on the coated Zr-TFMG and ZrO 2 . In vitro corrosion studies showed that the Zr-based TFMG and ZrO 2 coatings sustained in the SBF, exhibited superior corrosion resistance to the bare crystalline Ti substrate. Wettability studies showed TFMG and ZrO 2 coatings with a hydrophobic nature, and the TFMG-coated SBF-submerged specimens showed a hydrophilic nature. The in vitro cell viability of MC3T3-E1 cells showed good cell proliferation and low cytotoxicity. The calcification deposits were evaluated by staining with alizarin red S, which showed a lower calcium formation on Zr-TFMG compared to ZrO 2 . The present work also aims to assess the assimilation behavior of Cp-Ti, Zr-TFMG and ZrO 2 in vivo by inserting the coated specimen in the femur of rats. After post-implantation of 8 weeks, specimens were examined by micro-CT evaluation. The bone contact ratios as calculated were 72.75%, 15.32% and 38.79%. Consequently, the bone affinity was Cp-Ti wire >ZrO 2 -coated Ti wire >Zr 48 Cu 36 Ag 8 Al 8 -coated Ti wire.

Electrochemical anodized titanium dioxide (TiO 2 ) nanotubes are of immense significance as electrochemical energy storage devices owing to their fast electron transfer by reducing the diffusion path and paving way to fabricating binder-free and carbon-free electrodes. Besides these advantages, when nitrogen is doped into its lattice, doubles its electrochemical activity due to enhanced charge transfer induced by oxygen vacancy. Herein, we synthesized nitrogen-doped TiO 2 (N-TiO 2 ) and studied its electrochemical performances in supercapacitor and as anode for a lithium-ion battery (LIB). Nitrogen doping into TiO 2 was confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical performance of N-TiO 2 nanotubes was outstanding with a specific capacitance of 835 µF cm -2 at 100 mV s -1 scan rate as a supercapacitor electrode, and it delivered an areal discharge capacity of 975 µA h cm -2 as an anode material for LIB which is far superior to bare TiO 2 nanotubes (505 µF cm -2 and 86 µA h cm -2 , respectively). This tailor-made nitrogen-doped nanostructured electrode offers great promise as next-generation energy storage electrode material., Competing Interests: The authors declare no conflict of interest.

Surface modifications of metallic implants are important in order to protect the underlying metals from the harsh corrosive environment inside the human body and to minimize the losses caused by wear. Recently, researches are carried out in developing bioactive surfaces on metallic implants, which supports the growth and proliferation of cells on to these surfaces. Titanium silicon nitride (TiSiN) hard nanocomposites thin films were fabricated on Ti alloys (Ti-6Al-4V) by pulsed direct current (DC) reactive magnetron sputtering. The films were characterized for its microstructural and electrochemical behavior. The higher charge transfer resistance (Rct) and positive shift in Ecorr value of TiSiN/Ti alloys than the bare Ti-alloys indicates a better corrosion resistance offered by the TiSiN thin films to the underlying substrates. The biological response to TiSiN/Ti alloys and control bare Ti-alloys was measured in vitro using cell-based assays with two main outcomes. Firstly, neither the Ti alloy nor the TiSiN thin film was cytotoxic to cells. Secondly, the TiSiN thin film promoted differentiation of human bone cells above the bare control Ti alloy as measured by alkaline phosphatase and calcium production. TiSiN thin films provide better corrosion resistance and protect the underlying metal from the corrosive environment. The thin film surface is both biocompatible and bioactive as indicated from the cytotoxicity and biomineralization studies., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Thin films of titanium carbonitride (TiCN) were fabricated by DC magnetron sputtering on medical grade steel. The biocompatibility of the coating was further enhanced by growing hydroxyapatite crystals over the TiCN-coated substrates using biologically activated ammonia from synthetic urine. The coatings were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM)-energy dispersive spectroscopy, and Raman spectroscopy. The electrochemical behavior of the coatings was determined in simulated body fluid. In addition, hemocompatibility was assessed by monitoring the attachment of platelets on the coating using SEM. The wettability of the coatings was measured in order to correlate with biocompatibility results. Formation of a coating with granular morphology and the preferred orientation was confirmed by SEM and X-ray diffraction results. The hydroxyapatite coating led to a decrease in thrombogenicity, resulting in controlled blood clot formation, hence demonstrating the hemocompatibility of the coating.

Titanium nitride (TiN)/niobium nitride (NbN) nanostructured multilayer coatings were prepared by DC reactive magnetron sputtering method using the combination of a titanium and niobium target and an Ar-N2 mixture discharge gas on to 316L stainless steel substrates. The coatings showed a polycrystalline structure with (111) for TiN and (101) for NbN preferential growth. Raman spectroscopy measurements on the multilayer films exhibited the characteristic peaks at 212, 303, 458 and 578 cm-1. A higher hardness of 38 GPa was observed for TiN/NbN coatings. Electrochemical polarization tests were performed in simulated biological fluid solutions at 37 degreesC in order to determine and compare the corrosion behavior of the coated and uncoated 316L SS substrates. The TiN/NbN multilayer coatings could improve the corrosion resistance of 316L SS substrate. The bacterial culture experiments were performed and the bacteria treated samples were examined by epi fluorescence microscope measurements.

Titanium/titanium nitride (Ti/TiN) nanoscale multilayered films were deposited onto 316L stainless steel substrates by reactive magnetron sputtering using a Ti target. Coatings characterized by X-ray diffraction showed that the stack possesses centered cubic structure. The X-ray photoelectron spectroscopy survey spectra on the etched surfaces of the stack film on steel exhibited the characteristic Ti2p, N1s, and O1s peaks at the corresponding binding energies 454.5, 397.0, and 530.6 eV, respectively. Platelet adhesion experiments were carried out to examine the interaction between blood and the materials in vitro. The results indicated that the smoothness and lower isoelectric point contribute to better hemocompatibility of the Ti/TiN nanoscale multilayered coating. The biomediated synthesis of calcium hydroxylapatite (HA) was carried out on coated substrates using calcium-depositing bacteria. The observation of low corrosion current density (I(corr)) for the calcium HA-coated Ti/TiN specimens in simulated body fluid confirmed their highly resistive nature under the testing condition., (© The Author(s), 2010.)

Nanoscale multilayered TiN/VN coatings were developed by reactive dc magnetron sputtering on 316L stainless steel substrates. The coatings showed a polycrystalline cubic structure with (111) preferential growth. XPS analysis indicated the presence of peaks corresponding to Ti2p, V2p, N1s, O1s, and C1s. Raman spectra exhibited the characteristic peaks in the acoustic range of 160-320 cm(-1) and in the optic range between 480 and 695 cm(-1). Columnar structure of the coatings was observed from TEM analysis. The number of adherent platelets on the surface of the TiN/VN multilayer, VN, TiN single layer coating exhibit fewer aggregation and pseudopodium than on substrates. The wear resistance of the multilayer coatings increases obviously as a result of their high hardness. Tafel plots in simulated bodily fluid showed lower corrosion rate for the TiN/VN nanoscale multilayer coatings compared to single layer and bare 316L SS substrate.

Abstract: Ti/TiN multilayers were deposited by DC reactive magnetron sputtering method using a titanium target and an Ar–N2 mixture discharge gas. XRD technique was employed to study the structure of the coatings and to observe the variations of structural parameters with substrate temperatures. An increase in grain size with increase of substrate temperature was observed. The components of Ti 2p doublet, related to TiN, TiON and TiO2, were observed in the core-level spectra of the deposited multilayer films from XPS analysis. A microhardness value of 25.5GPa was observed for Ti/TiN multilayers prepared at 400°C. Electrical properties were found to depend on substrate temperature. [ABSTRACT FROM AUTHOR]

Abstract Nanopowders of 45 s5 bioactive glass were synthesized by simple sol-gel technique. The powder was characterized for their microstructure and morphology. X-ray diffraction (XRD) pattern of the synthesized powder showed no reflections. The electron micrograph showed an agglomerated particle distribution with an average hydrodynamic particle size of 450 nm. Nanocomposite bioactive glass – nanoclay was prepared by physical mixing, which were then coated onto titanium substrates by electrophoretic deposition. The coatings were characterized for their morphology. The XRD pattern confirmed the presence of nanoclay in the coating. The scanning electron microscopy (SEM) images showed a densification of the coatings as the concentration of nanoclay was increased in the nanocomposites. The corrosion resistance of the nanocomposite coatings was studied in simulated body fluid. The charge transfer resistance increased from 9 × 103 Ω for uncoated substrates to 2.8 × 105 Ω for nanocomposite coatings. Potentiometric polarization studies also showed a similar trend, showing consistency in the electrochemical analysis. Highlights • Nanocomposites of Bioactive glass and kaolinite nanoclay were electrophoretically deposited on Ti substrates • A densification of coating was observed as the concentration of nanoclay was increased in the nanocomposites • The nanocomposite composition with highest nanoclay content showed an improved corrosion resistance [ABSTRACT FROM AUTHOR]

The main aim of this study was to apply high-energy longer mechanical milling and spark plasma sintering (SPS) techniques to produce in-situ α-Ti/TiO 2 /TiC hybrid composites from commercially pure-Ti (CP–Ti, HCP structure) powders. The CP-Ti powders were subjected to different milling times (0, 20, 40, 60, 80, 100, and 120 h). The results showed that the powder samples milled for 120 h produced Ti, Ti 3 O 5 , TiO, TiO 2 phases, and dissolved C atoms from the process control agent (toluene) which were then converted to α-Ti, TiO 2 , and TiC phases (formed in-situ composites) through spark plasma sintering. This was expected due to more reactivity in the 120 h sample as longer milling introduces severe and robust structural refinements. Structural evaluations with increasing milling time were carried out using XRD, HRSEM, and HRTEM. The synthesized powders were then consolidated by SPS at pressures of 50 MPa and 1323 K for 6 min. The micro-hardness results have shown that the hardness was started to increase from 1.40 GPa to 5.56 GPa with increasing milling time due to more dislocation and pinning effect produced by grain refinement and formed TiO 2 /TiC intermetallic particles enhancing the strength of α-Ti matrix. The α-Ti/TiO 2 /TiC in-situ hybrid composite bulk sample yielded an ultimate compressive strength of 1.594 GPa. [ABSTRACT FROM AUTHOR]

Surface-modified implant materials with improved physicochemical properties and biocompatibility are vital for determining osseointegration and to enhance bone anchorage. Herein, titanium boron nitride (TiBN) thin films of thickness 3.4 μm were coated as an interlayer on sandblasted Ti plates by confocal D.C. magnetron sputtering using Ti and TiB 2 targets. Nanoindentation tests showed a hardness of 27 GPa for the thin film. The bioactivity of the as-prepared coatings was enriched by introducing bioglass (BG), 45S5, overlay via electrophoretic deposition. The nanocrystalline microstructure with lattice parameter 4.2 Å, surface topology and vibration modes/surface chemistry of the coatings were comprehensively studied using microscopic and spectroscopic techniques. Swab inoculation assay, cellular viability assay and hemocompatibility studies revealed that bioglass overlaid thin films exhibited antibacterial property and cytocompatibility with no clot formation. Contact angle measurements showed that 45S5 bioglass-coated substrates were hydrophilic. Biocorrosion studies of the prepared implant materials in simulated body fluid (SBF) revealed the corrosion resistance of bioglass overlaid specimens with the corrosion potential (E corr) shifting towards a relatively positive value and the corrosion current density (I corr) decreasing in the order bare Ti > TiBN >45S5/TiBN coated Ti substrates. Obtained experimental results suggests that the as-prepared 45S5 glass-coated TiBN/Ti plates could be a potential implantable candidate with synergistic cytocompatibility and corrosion resistance. [Display omitted] • Boron-incorporated ternary transition metal nitride (TiBN) thin films were developed by reactive sputtering. • The thin films were found that the film is a nanocomposite of crystalline TiN and amorphous BN. • The bioactivity of the thin film was enhanced by electrophoretically depositing 45S5 bioglass. • Biocompatibility of the thin film was evaluated by hemocompatibility, cytocompatibity and antibacterial activity. • The film acted as a protective topcoat in underlying metal from corrosive environment. [ABSTRACT FROM AUTHOR]