Treated Ti Substrate Research Articles

2D magnesium phosphate resorbable coating to enhance cell adhesion on titanium surfaces

Titanium and its alloys are essential metals for orthopedic implant manufacturing due to their exceptional mechanical properties and biocompatibility, used extensively for treating various orthopedic conditions. However, Titanium (Ti) implants have a disadvantage due to lack of bioactivity, potentially affecting osseointegration and osteoconductive capabilities, and may take several months to integrate with bone tissue. In this work, we prepared a layer of 2D magnesium phosphate (MgPi) coating on the surface of titanium surfaces via the spin-coating technique. Various techniques were used to study the phase composition of the coatings, including FTIR, Raman spectroscopy, NMR, and XRD analysis. Morphology and chemical analysis were performed using Atomic force microscopy and SEM/EDX. Nano-scratch test and water contact angle measurements were used to measure adhesion strength and wettability. In addition, in vitro cell assays were used to assess cell adhesion and viability to determine how the MC3T3-E1 osteoblast-like cells reacted to the different treated Ti substrates. AFM results showed that the surface roughness became lower after coatings. MgPi-coated samples showed higher hydrophilicity, protein adsorption, and cell viability than uncoated samples. The nano-scratch test showed that the MgPi coating showed better adherence to chemically and thermally treated samples compared to untreated samples. The deposited MgPi coating has good adhesion to the Ti-substrates. Most significantly, compared to uncoated control (Ti) (p < 0.005) and chemically treated coated samples CT-MgPi (p < 0.005), MC3T3-E1 cell proliferation was significantly increased on thermochemical coated surfaces. These findings point to resorbable two-dimensional MgPi coatings as a potential candidate for promoting Ti implant osseointegration.

Titanium-based substrate modified with nanoenzyme for accelerating the repair of bone defect

Titanium (Ti) and titanium alloy are the most common metal materials in clinical orthopedic surgery. However, in the initial stage of surgery and implantation, the production of excessive reactive oxygen species (ROS) can induce oxidative stress (OS) microenvironment. OS will further inhibit the growth of new bone, resulting in surgical failure. In this study, based on the fact that nanoscale manganese dioxide (MnO2) can show H2O2-like enzyme activity, a MnO2 nanocoating was prepared on mciro-nano structured surface of Ti substrate via a two-step method of alkaline thermal and hydrothermal treatment. The results of scanning electron microscopy (SEM), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) showed that the nano-MnO2 coating was successfully fabricated on the surface of Ti substrate. The results of measurement of H2O2, dissolved O2 and intracellular ROS in vitro showed that the treated Ti substrate could efficiently eliminate H2O2 and reduce ROS. Furthermore, the modified Ti substrate could promote the early adhesion, proliferation and osteogenic differentiation of MSCs, which was demonstrated by experimental results of cell morphology, cell viability, alkaline phosphatase, collagen, and mineralization deposition. The results of quantitative real-time polymerase chain reaction (qRT-PCR) of MSCs adhered the modified Ti substrate showed that the expression of genes related to osteogenic differentiation significantly increased. More importantly, the modified Ti implant could eliminate ROS at the injury site, reduce OS and promote the regeneration of bone tissue, which was demonstrated via hematoxylin/eosin, Masson's trichrome and immunohistochemical staining. In conclusion, the modified Ti implant presented here had the effect of reducing OS and promoting osseointegration. Relevant research ideas and results provide new methods for the research and development of functional implants, which have potential application value in the field of orthopedics.

Promoting osteoblast proliferation and differentiation on functionalized and laser treated titanium substrate using hydroxyapatite/β-tricalcium phosphate/silver nanoparticles

In the present study, a novel composite coating consisting of nano-silver (nAg) with an association of hydroxyapatite (HA)- β-tricalcium phosphate (β-TCP) particles was developed by surface coating onto Ti substrate through two different but aligned steps: first nAg-HP (containing a different ratio of HA and β-TCP particles) composite was coated by sol-gel technique with the association of poly (vinyl alcohol) (PVA) as a binding agent to the substrate, then continuous CO2 laser treatment was carried out to improve the surface properties. The physicochemical properties of fabricated coatings were evaluated by using X-ray diffractometry (XRD), and field emission scanning electron microscopy (FESEM) equipped with energy dispersive X-ray detector (EDX). The biological properties of composite coatings were observed by bioactivity measurement, antibacterial performance, MTT assay, and real-time PCR. The FESEM images and cross-section micrographs showed that the particles were distributed homogenously, and the interface was well-integrated. Mineralization assessment revealed treated surface was a better place for apatite nucleation and growth. The antibacterial measurement showed Ag nanoparticles enhanced significantly antibacterial activity reached up about 90%. The mRNA expression level for COL1A1, ALP, RUNX2, OCT, and GAPDH revealed the positive effect of functionalized and treated Ti substrate on osteoblast cell differentiation. The composite coating illustrated enhanced biological properties suggesting it is a promising candidate for further studies for practical biomedical applications.

A new approach to understanding the deficiency of backside illuminated dye-sensitized solar cells’ fill factor as a result of cracking of the TNAs

Abstract In this work, a new approach was taken to gain an insight into the deficiency of backside illuminated dye-sensitized solar cells’ fill factor as a result of cracking of the TNAs. In order to obtain cracked and non-cracked TNAs and compare their properties and performance in backside illuminated DSSCs, anodization was carried out respectively using pretreated Ti substrates covered with TiO2 nanoparticles and bare Ti substrates. To cover the Ti substrates with 20-30 nanometer-sized TiO2 nanoparticles, they were conventionally TiCl4 treated. The SEM images of the anodized TNAs approved the sever and wide cracking of the TNAs grown on TiCl4 treated Ti substrates compared to those of grown on bare Ti substrates. The reason for this phenomenon could be the accumulation and stacking of the nanoparticles among the bundles of the TNAs. It is approved by narrower peaks of the XRD patterns for TiCl4 treated TNAs and the observed stacks of nanoparticles in the intersectional SEM images. The anodized TNAs grown both on TiCl4 treated and bare Ti substrates were applied as photoanodes in backside illuminated DSSCs. All the photovoltaic parameters other than fill factor and the consequent efficiency obtained from both the grown TNAs on TiCl4 treated and bare Ti substrates were equal. Whereas, the fill factor and efficiency of the DSSCs using cracked TNAs (grown on TiCl4 treated Ti substrates) were approximately 9% lower. This deficiency of the DSSCs is attributed to the presence of the nanoparticles and cracking of the TNAs which result in an increase of series resistance in the cell.

Magnesium-particle/polyurethane composite layer coating on titanium surfaces for orthopedic applications

This study aimed to design an adhesive biodegradable polymer layer on the surface of titanium (Ti) implants for enhanced surface bioactivity. To this end, a coating of magnesium-particles doped biodegradable polyurethane (PU) was introduced as a composite layer on Ti surfaces using a simple spin coating technique. The coating’s performance and characteristics were investigated in terms of the surface topography, composition, surface roughness, wettability, adhesion and electrochemical behavior of composite coatings on untreated (polished) and alkaline treated Ti substrates. Interestingly, the Ti samples coated with the composite layers showed superior corrosion resistance compared to the uncoated samples. Additionally, the coating on alkali-treated Ti surfaces demonstrated enhanced adhesion (5B, measured by cross-cut test) compared to the coating on untreated Ti (1B), indicating the vital role of the alkaline-treatment step. A composite thin layer coated on alkaline-treated Ti enhanced osteoblastic-like (MC3T3-E1) cellular adhesion and cell proliferation and was found to support osteoblastic differentiation compared to uncoated alkaline-treated Ti. Surface modification of alkaline-treated Ti with a biodegradable Mg-particles/PU thin layer appears to be a promising strategy for developing surface bioactivity of orthopedic devices.

Effect of Ti Substrate Ion Implantation on the Physical Properties of Anodic TiO2 Nanotubes

The influence of nitrogen-ion implantation on the titanium (Ti) surface is studied. The nontreated Ti and the Ti treated with ion implantation were anodized in an ethylene-glycol-based electrolyte solution containing 0.3 wt% ammonium fluoride (NH4F) and 3 vol% deionized (DI) water at a potential of 60 V for 1 h at room temperature. The current density during the growth of the TiO2 nanotubes was monitored in-situ. The surface roughnesses of the Ti substrates before and after the ion implantation were investigated with atomic force microscopy (AFM). The surface roughness was lower for the treated Ti substrate. The morphology of the anodic TiO2 nanotubes was studied by using field-emission scanning electron microscopy (FESEM). Clearly, the titanium nanotubes grown on the treated substrate were longer. In addition, some ribs were observed on their walls. The optical band gap of the anodic TiO2 nanotubes was characterized by using a diffuse reflection spectral (DRS) analysis. The anodic TiO2 nanotubes grown on the treated Ti substrate revealed a band gap energy of approximately 3.02 eV.

Effects of hydrothermal sterilization on properties of biological coating fabricated by alkaline-heat treatment on titanium

Alkaline-heat (AH) treatment is a feasible method to prepare Titanium (Ti) based metals with an active ceramic coating for biological applications. Currently, the AH treated Ti substrates are usually sterilized with ethylene oxide gas (EO) or Gamma-ray irradiation (GI) before biological experiments and clinical implantation. However, the EO process is complex and residual gas is toxic for tissue and cells whereas radioactive source is difficult to access for GI and therefore both methods are not practical for dental offices and laboratories. Previously, hydrothermal sterilization (HS) was proposed for all kinds of Ti based endosseous implants and had been proven promising for clinical applications due to its advantage of restoring the osseointegration of Ti implants stored for long-term. In this study, the effects of HS on properties of AH treated Ti were studied in comparison with conventional autoclaving (AC). Both sterilizations were carried out at 121 °C for 20 min in a common autoclave and distilled water was used as medium for HS only. Results showed that, both AC and HS altered the nano-structure of the ceramic coating formed by AH and caused significant Sodium (Na) loss. AC decreased crystallinity of the coating by forming numerous nano-sheets, whereas HS increased the crystallinity, densified the coating and improved its scratch resistance. AC depressed the formation of apatite, in contrast, a complete apatite layer was formed on the HS specimen after being immersed in simulated body fluid (SBF) for 4 days. Both attachment and proliferation of osteoblast-like MC3T3-E1 cells on the HS specimens were better than that on the AC ones. Decontamination, superhydrophilicity and high crystallinity from HS were believed to be the main contributors. In summary, the current results showed that HS can be used as a sterilization method for AH treated Ti implants in biomedical applications.

Surface engineering of titanium implants with enzyme-triggered antibacterial properties and enhanced osseointegration in vivo.

Preventing bacterial infection and improving the osseointegration of titanium (Ti) and its alloys are both highly crucial factors for their long-term successful implantation in clinical applications. However, the straightforward applications of antibacterial surfaces on Ti-based materials remain limited due to their side effects on cytocompatibility. Herein, catechol-functionalized multilayer films composed of dopamine-modified hyaluronic acid (HA-c) and 3,4-dihydroxyhydrocinnamic acid-modified chitosan (Chi-c) were developed on Ti substrates modified with TiO2 nanotube arrays loaded with an antibacterial drug. The treated Ti substrate showed strong hydrophilicity, with a water contact angle of about 20°, and obviously inhibited early-stage bacterial adhesion. Moreover, this system displayed an enzyme-responsive release of antibacterial drug triggered by the hyaluronidase degradation of HA-c, which exhibited effective antibacterial ability and eliminated side effects caused by burst release of antibiotics. Meanwhile, the modified Ti substrates significantly promoted initial osteoblast adhesion through up-regulating the expression of adhesion-related genes, including integrin αv and β3. More importantly, this prepared coating with bacterial self-responsiveness improved osseointegration and prevented bacterial infection of Ti implants in vivo. Overall, our developed catechol-functionalized and bacterial self-responsive coating on Ti substrate has great significance in clinical applications of orthopedic and dental implants.

Surface modification of titanium substrates for enhanced osteogenetic and antibacterial properties

The insufficient osseointegration and bacterial infection of titanium and its alloys remain the key challenges in their clinic applications, which may result in failure implantation. To improve osteogenetic and antibacterial properties, TiO2 nanotube arrays were fabricated on titanium substrates for loading of antibacterial drug. Then, TiO2 nanotube arrays were covered with chitosan/sodium alginate multilayer films. The successful construction of this system was verified via scanning electron microscopy and contact angle measurement. The cytocompatibility evaluation in vitro, including cytoskeleton observation, cell viability measurement, and alkaline phosphatase activity assay, confirmed that the present system was capable of accelerating the growth of osteoblasts. In addition, bacterial adhesion and viability assay verified that treated Ti substrates were capable of reducing the adhesion of bacteria. This study may provide an alternative to develop titanium-based implants for enhanced bone osseointegration and reduced bacterial infection.

Surface bioactivation through the nanostructured layer on titanium modified by facile HPT treatment

Facile fabrication of nanostructured surface is of great importance for the use of titanium (Ti) implants in biomedical field. In this study, a low-cost and easy-to-operate method called HPT (hydrothermal & pressure) here has been developed and used to fabricate the expected nanostructured surface on Ti substrates. The effects of experimental parameters on the morphology of Ti surface were investigated and characterized. The results indicated that by altering the hydrothermal pressure, NaOH concentration and treating time, surface nanostructure like nanopetals or nanoflakes could be formed on the surface of Ti substrates. The orthogonal experiments were conducted to demonstrate the optimized operation conditions. A formation mechanism of the nanostructured titanate layer was proposed, revealing that the nanostructured layer could be formed via a special upward and downward co-growth manner. In vitro cell culture showed that the HPT treated Ti substrates, especially the T-10 sample, could greatly enhance the cell-material interactions, i.e. the cell proliferation and differentiation, focal protein adhesion, and osteogenic factor expression. The HPT method paves a new way to modify the surface of Ti implants with better bioactivity and promising prospect for future biomedical applications.

Electrodeposition of Adherent Polypyrrole Film on Titanium Surface with Enhanced Anti-corrosion Performance

A method of producing extremely adhesive polypyrrole film on Titanium (Ti) substrate was investigated. The Ti substrate was chemically pretreated and then modified by polydopamine (PDA), the polypyrrole film synthesized by electrochemical method on the treated Ti substrate displayed good adhesion and enhanced anticorrosion performance. The study of the corrosion process was conducted through open circuit potential, tafel polarization and alternating current impedance test. The adhesive polypyrrole film coated titanium showed higher positive shift in corrosion potential and lower corrosion rate, indicating the great enhanced anti-corrosion performance.

Correlation between surface properties and wettability of multi-scale structured biocompatible surfaces

The influence of surface properties of radio-frequency (RF) magnetron deposited hydroxyapatite (HA) and Si-containing HA coatings on wettability was studied. The composition and morphology of the coatings fabricated on titanium (Ti) were characterized using atomic force microscopy (AFM) and X-ray diffraction (XRD). The surface wettability was studied using contact angle analysis. Different geometric parameters of acid-etched (AE) and pulse electron beam (PEB)-treated Ti substrates and silicate content in the HA films resulted in the different morphology of the coatings at micro- and nano- length scales. Water contact angles for the HA coated Ti samples were evaluated as a combined effect of micro roughness of the substrate and nano-roughness of the HA films resulting in higher water contact angles compared with acid-etched (AE) or pulse electron beam (PEB) treated Ti substrates.

A study on the performance of IrO2–Ta2O5 coated anodes with surface treated Ti substrates

Oxalic acid etching and hydrogen treatment were applied on Ti substrates of IrO2–Ta2O5 coated anodes. The coatings were prepared by thermal decomposition of a mixture of H2IrCl6·6H2O dissolved in hydrochloric acid and TaCl5 dissolved in alcohol. Surface morphology, microstructure, matter phase, electrochemical properties and accelerated life of the anodes were observed and examined. Compared with the anode without its substrate treated, the anodes with the substrates oxalic acid etched and hydrogen treated at 300°C, 400°C, 500°C and 600°C respectively show better electro-catalytic performance and longer life. However, effects of two methods are different. Oxalic acid etching of the substrate, which could get better improvement at accelerated life, while hydrogen treatment of the substrates, which could get better improvement at the electro-catalytic performance. Especially, anode with 400°C hydrogen treated substrate has the highest electro-catalytic activity.

Enhanced osteointegration of medical titanium implant with surface modifications in micro/nanoscale structures

Biomimetic design and substrate-based surface modification of medical implants will help to improve the integration of tissue to its material interfaces. Surface energy, composition, roughness, and topography all influence the biological responses of the implants, such as protein adsorption and cell adhesion, proliferation and differentiation. In the current study, different surface structures of Ti implants were constructed using facile surface techniques to create various micro-, nano-, and nano/micro composite scale topography. We have fabricated three types of hierarchical structures of TiO2 coating on Ti implants, including nanotube structure, nano sponge-like structure, and nano/micro nest-like structure. The osteointegration and biomechanical performance of the coated Ti screws were evaluated by histology and removal of torque force test in vivo. We found that the nano/micro nest-like and nanotube structured surface possessed better osteointegration ability. It indicated that the alkaline hydrothermally treated Ti substrate was the best for bone-implant integration in terms of all in vitro and in vivo testing parameters. The alkaline hydrothermally treated surface displayed a hydrophilic (contact angle value 5.92 ± 1.2), higher roughness (Ra value 911.3 ± 33.8 nm), higher specific surface area (8.26 ± 1.051 m2/g), and greater apatite inductivity. The electrochemical surface modification may become a powerful approach to enhance metal implant to bone integration in orthopaedic applications.

Development of lotus-like hydroxyapatite coating on HELCDEB treated titanium by pulsed electrodeposition

Pure titanium (Ti) was irradiated using high energy low current electron beam (HELCDEB) with a concentrated energy flow of 500keV at 1.5mA beam current. The irradiated Ti surface was coated with hydroxyapatite (HAP) by pulsed electrodeposition (PED) with the optimum concentration of 2000ppm H2O2 at current density 1mA/cm2. The HRSEM characterization of HAP coating on the HELCDEB treated Ti substrate exhibited lotus flower-like morphology. The corrosion resistivity of HAP coating on the HELCDEB treated Ti was investigated by the potentiodynamic polarization technique, which shows desired bioresistivity in simulated body fluid (SBF). The as-coated HAP can immensely serve as a potential candidate for biomedical applications.

Calcium phosphate growth at electropolished titanium surfaces.

This work investigated the ability of electropolished Ti surface to induce Hydroxyapatite (HA) nucleation and growth in vitro via a biomimetic method in Simulated Body Fluid (SBF). The HA induction ability of Ti surface upon electropolishing was compared to that of Ti substrates modified with common chemical methods including alkali, acidic and hydrogen peroxide treatments. Our results revealed the excellent ability of electropolished Ti surfaces in inducing the formation of bone-like HA at the Ti/SBF interface. The chemical composition, crystallinity and thickness of the HA coating obtained on the electropolished Ti surface was found to be comparable to that achieved on the surface of alkali treated Ti substrate, one of the most effective and popular chemical treatments. The surface characteristics of electropolished Ti contributing to HA growth were discussed thoroughly.

In situ composite coating of titania–hydroxyapatite on titanium substrate by micro-arc oxidation coupled with electrophoretic deposition processing

Abstract In situ composite coating of hydroxyapatite (HA)/TiO 2 were produced on titanium (Ti) substrate by micro-arc oxidation coupled with electrophoretic deposition (MAO&EPD) technique with different concentrations of HA particles in the 0.2 M NaOH electrolyte solution. The surface morphology and chemical composition of the hybrid coating were effected by HA concentration. The amount of HA particles incorporated into coating layer increased with increasing HA concentration used in the electrolyte solution. The corrosion behavior of the coating layer in simulated body fluids (SBF) was evaluated using a potentiodynamic polarization test. The corrosion resistance of the coated sample was increased compared to the untreated Ti sample. The in vitro bioactivity assessment showed that the MAO&EPD treated Ti substrate possessed higher apatite-forming ability than the untreated Ti. Moreover, the apatite-forming ability had a positive correlation with HA concentration. In addition, the cell behavior was also examined using cell proliferation assay and alkaline phosphatase ability. The coating formed at HA concentration of 5 g/L exhibited the highest cell ability.

Hydroxyapatite coating on the titanium substrate modulated by a recombinant collagen-like protein

Plenty of techniques have been developed to modify the surface character of titanium (Ti) and its alloys in order to realize their biological bond to natural bone. In this work, a biomimetic process was employed to form a hydroxyapatite (HAp) coating on the alkali-heat treated Ti substrate in 1.5 times simulated body fluid (1.5 × SBF) with the addition of a recombinant collagen-like protein. The coating was characterized using SEM-EDX, FESEM, and XRD. Results showed that the recombinant collagen-like protein could accelerate the preferential nucleation and directional growth along c axis of HAp on the pretreated Ti substrates. The investigation of in vitro cell cultivation showed that the existence of recombinant collagen-like protein in coating could improve the initial cell adhesion, proliferation and differentiation of MG-63 cells, which implied the materials possessed excellent biocompatibility and had a wide potential in biomedical application.

Facile preparation of PbO 2 electrode for the electrochemical inactivation of microorganisms

The electrochemical inactivation of microorganisms using Escherichia coli as testing species by a novel PbO 2 electrode was investigated. The PbO 2 electrode was constructed by electrochemical deposition of PbO 2 on the treated Ti substrate in the fluorine (F) doped ionic liquids/water (ILs/H 2O) two phase solution. Then, it was characterized by XRD and SEM analysis. Further investigation showed that the crystal size of electrodeposited PbO 2 became smaller with the increase of ILs concentration in the electrolyte solution. The small crystal size favored to the generation of the absorbable OH on the electrode surface, which was proved to play a key role during the disinfection process. TEM investigation revealed the morphological change of the E. coli cells during the bactericidal process.

Characterization of a bioactive nanotextured surface created by controlled chemical oxidation of titanium

Events at bone–implant interfaces are influenced by implant surface properties. Our previous work has revealed that osteogenic activity is enhanced by a nanotextured Ti surface, obtained by controlled chemical oxidation using a H 2SO 4/H 2O 2 mixture. To better understand the origin of this biological effect, we have carried out a characterization of the modified surface at the nanoscale. In particular, the morphology, structure, and chemical composition of the Ti surface were examined thoroughly. X-ray photoelectron spectroscopy (XPS), combined with grazing-angle Fourier-transform infrared (FTIR) spectroscopy, revealed that the oxidized Ti surface consists of almost pure TiO 2 with Ti:O ratio ranging between 1:2.02 and 1:2.08. Raman spectroscopy and X-ray diffraction (XRD) indicated that the chemically treated Ti surface is mainly composed of amorphous titania. Scanning electron microscopy (SEM) clearly showed that the treated Ti substrate becomes highly porous and has a surface consisting of nano-sized pits, which have average diameters and fractal dimensions ranging between 20–22 nm and 1.11–1.17, respectively. Atomic force microscopy (AFM) revealed a three–fold increase in surface roughness. The thickness of the oxide layer on the treated Ti surface is estimated to be ∼32–40 nm. Together, these observations provide a detailed characterization of chemically oxidized Ti surfaces at the nanoscale and offer new prospects for understanding and controlling the relationship between the properties of materials and their interactions with cells. Our work brings us closer to the creation of “intelligent” implant surfaces, capable of selectively influencing cell behavior.