Bioceramic Coatings Research Articles

Synthesis of nanostructured hardystonite (HT) bioceramic coated on titanium alloy (Ti-6Al-4V) substrate and assessment of its corrosion behavior, bioactivity and cytotoxicity

Bioceramic coatings have had a significant impact on the realm of biomaterials and medical devices in recent decades. In this study, synthesized hardystonite coating (Ca2ZnSi2O7) by sol–gel method was applied on titanium substrate (Ti-6Al-4V) using electrophoretic deposition method. XRD patterns and EDX result confirm the pure hardystonite phase structure. Transmission electron microscopy was confirmed the appeared round morphology and nanometer size of the synthesized hardystonite particles. Additionally SEM analysis was approved that the hardystonite coating is able to make a uniform and flawless apatite with needle-like and cauliflower forms during prolonged exposure to SBF. The Ringer’s solution Tafel test results were indicated that the corrosion resistance of twice-coated samples is increased by increasing the voltage to 50 Voltages so that the corrosion current density in the twice coated samples is less than the bare samples. In vitro evaluation by MTT assay was confirmed the viability of the bone marrow stem cells so that hardystonite increases the vitality and reproduction of stem cells at low concentration which makes the hardystonite coating a suitable candidate for clinical applications.

Surface functionalized bioceramics coated on metallic implants for biomedical and anticorrosion performance - a review.

In modern days, the usage of trauma fixation devices has significantly increased due to sports injury, age-related issues, accidents, and revision surgery purposes. Numerous materials such as stainless steel, titanium, Co-Cr alloy, polymers, and ceramics have been used to replace the missing or defective parts of the human body. After implantation, body fluids (Na+, K+, and Cl-), protein, and blood cells interact with the surface of metallic implants, which favours the release of ions from the metallic surface to surrounding body tissues, leading to a hypersensitive reaction. Body pH, temperature, and interaction of immune cells also cause metal ion leaching and lose host cell interaction and effective mineralization for better durability. Moreover, microbial invasion is another important crisis, which produces extracellular compounds onto the biomaterial surface through which it escapes from the antimicrobial agents. To enhance the performance of materials by improving mechanical, corrosion resistance, antimicrobial, and biocompatibility properties, surface modification is a prerequisite method in which chemical vapour deposition (CVD), physical vapour deposition (PVD), sol-gel method, and electrochemical deposition are generally involved. The properties of bioceramics such as chemical inertness, bioactivity, biocompatibility, and corrosion protection make them most suitable for the surface functionalization of metallic implants. To the best of our knowledge, very limited literature is available to discuss the interaction of body proteins, pH, and temperature onto bioceramic coatings. Hence, the present review focuses on the corrosion behaviour of different ceramic composite coating materials with different conditions. This review initially briefs the properties and surface chemistry of metal implants and the need for surface modifications by different deposition techniques. Further, mechanical, cytotoxicity, antimicrobial property, and electrochemical behaviour of ceramics and metal nitride coatings are discussed. Finally, future perspectives of coatings are outlined for biomedical applications.

In Vitro Electrochemical Behavior of Sol‐Gel Derived Hydroxyapatite/Graphene Oxide Composite Coatings on 316L SS for Biomedical Applications

AbstractDevelopment of bioceramic coatings on the metallic implant surface with superior properties such as good bonding strength, better corrosion resistance and bioactivity was one of the key tasks for the present biomaterial scientists. Hydroxyapatite (Ca10 (PO4)6(OH)2) was one of the hopeful calcium phosphate‐based ceramic biomaterials which can be enforced as a layer on the metallic substrate due to its resemblance with the human bone in chemical composition. Current effort defines the in‐situ blending of HAP/graphene oxide composite by the sol‐gel process. The prepared HAP/GO composites were characterized using FT‐IR, XRD, SEM and TEM analysis. A triple‐layered composite coating was attained at the spin speed of 3000 rpm/min further sintered at 600 °C for 2 hrs. In‐vitro corrosion resistance behavior of the coatings on 316 L SS implant were studied on simulated body fluid. The average crystallite size of the synthesized powders was reduced from 40.58 to 21.08 nm with the addition of graphene oxide, anti‐bacterial study for the HAP/GO composite powder competently inhibits the growth of pathogens. Electrochemical studies and adhesion studies showed increased corrosion resistance with superior bonding strength on 316 L SS surface, which results its use for long term biomedical applications.

Mechanical properties of warm sprayed HATi bio-ceramic composite coatings

To explore a new approach for fabricating the load bearing implants with the combination of bioactivity, biocompatibility, and mechanical properties, mechanically mixed hydroxyapatite (HA) and titanium (Ti) powders containing 30, 50, and 70 wt% Ti were sprayed onto a 316L stainless steel substrate using a warm spray (WS) process. The microstructures, phase compositions, chemical structures, and mechanical properties of WS HATi composite coatings were comprehensively investigated and compared to those of WS HA coating. Experimental results indicate that the cross-sectional microstructures of WS HATi composite coatings present typical lamellar structures composed of curved stripes formed by well-deformed and oxidized Ti splats and limited deformed HA splats, and are significantly influenced by the Ti content in the original powders. Phase constitutions of the composite coatings mainly consist of HA, Ti, TiO2, and TiO. Chemical structures of HA in the composite coatings deposited using powders with Ti content less than 30% are similar to the structures in the original powder. The microhardness, elastic modulus, and bond strength of the coatings increased from 0.32 ± 0.15 GPa to 1.41 ± 0.31 GPa, from 1.37 ± 0.28 GPa to 23.28 ± 3.45 GPa, and from 17.3 ± 2.2 MPa to 34.8 ± 3.2 MPa, respectively. The abrasive wear weight loss of the coatings on Al2O3 abrasive paper decreased from 2.9 mg to 1 mg, as the addition of Ti particles in original powders increased from 0 to 70%.

Multifunctional hopeite nanocoating on Ti64 substrates by pulsed laser deposition and radio frequency magnetron sputtering for orthopedic implant applications: A comparative study

Functionalized implants demonstrate an upgraded approach in orthopedic implants, aiming to achieve long term success through improved bio integration. Bioceramic coatings with multifunctionality have arisen as an effective substitute for conventional coatings, owing to their combination of various properties that are essential for bio-implants, such as osteointegration and antibacterial character. In the present study, thin hopeite coatings were produced by Pulsed laser deposition (PLD) and radio frequency magnetron sputtering (RFMS) on Ti64 substrates. The obtained hopeite coatings were annealed at 500 °C in ambient air and studied in terms of surface morphology, phase composition, surface roughness, adhesion strength, antibacterial efficacy, apatite forming ability, and surface wettability by scanning electron microscope (SEM), X-ray diffraction (XRD), atomic force microscope (AFM), tensometer, fluorescence-activated cell sorting (FACS), simulated body fluid (SBF) immersion test and contact angle goniometer, respectively. Furthermore, based on promising results obtained in the present work it can be summarized that the new generation multifunctional hopeite coating synthesized by two alternative new process routes of PLD and RFMS on Ti64 substrates, provides effective alternatives to conventional coatings, largely attributed to strong osteointegration and antibacterial character of deposited hopeite coating ensuring the overall stability of metallic orthopedic implants.

Bioactive multifunctional hopeite coatings on new generation SS254 steel by laser rapid manufacturing for bone implant applications

ABSTRACT Overall long-term success of metallic bone implant is mainly governed by the two key factors osseointegration and antibacterial function. Bioceramic hopeite coatings have been proven effective for getting strong osseointegration and antibacterial character. However, deterioration of hopeite coatings during the implantation period can adversely affect their overall biological performance. To overcome this issue, the present research work recommends an innovative process route of laser rapid manufacturing (LRM) for depositing hopeite coatings with good metallurgical bonding. Microstructure, phase composition, microhardness, antibacterial efficacy, and bioactivity were evaluated through Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), a Vickers microhardness tester, Fluorescence-Activated Cell Sorting (FACS) technique, and a Simulated Body Fluid (SBF) immersion test respectively. The promising results obtained from these characterisations and testing establishes the new process route LRM as an effective alternative to deposit multifunctional hopeite coatings on metallic prosthetic-orthopaedic implants.

Multifunctional hydroxyapatite and hopeite coatings on SS254 by laser rapid manufacturing for improved osseointegration and antibacterial character: A comparative study.

Orthopaedic metallic implant's long-term success strongly depends upon the two main factors: osseointegration and antibacterial character. Bioceramic (hydroxyapatite and hopeite) coatings have been proven effective for getting strong osseointegration and antibacterial character. However, deterioration of bioceramic coatings during the implantation period can adversely affect its overall biological performance. To conquer this issue, this research work recommends an innovative process route of laser rapid manufacturing for depositing bioceramic (hydroxyapatite and hopeite) coatings with metallurgical bonding. Microstructure, phase composition, antibacterial efficacy and bioactivity were evaluated using scanning electron microscopy, X-ray diffraction, fluorescence-activated cell sorting technique and simulated body fluid immersion test. The promising results obtained from these characterizations and testing establish the new process route laser rapid manufacturing as an effective alternative to deposit multifunctional bioceramic (hydroxyapatite and hopeite) coatings on metallic prosthetic-orthopaedic implants.

Novel Yttria-Stabilized Zirconium Oxide and Lithium Disilicate Coatings on Titanium Alloy Substrate for Implant Abutments and Biomedical Application.

This study aimed to create novel bioceramic coatings on a titanium alloy and evaluate their surface properties in comparison with conventional prosthetic materials. The highly polished titanium alloy Ti6Al4V (Ti) was used as a substrate for yttria-stabilized zirconium oxide (3YSZ) and lithium disilicate (LS2) coatings. They were generated using sol-gel strategies. In comparison, highly polished surfaces of Ti, yttria-stabilized zirconium oxide (ZrO2), polyether ether ketone (PEEK) composite, and poly(methyl methacrylate) (PMMA) were utilized. Novel coatings were characterized by an X-ray diffractometer (XRD) and scanning electron microscope (SEM). The roughness by atomic force microscope (AFM), water contact angle (WCA), and surface free energy (SFE) were determined. Additionally, biocompatibility and human gingival fibroblast (HGF) adhesion processes (using a confocal laser scanning microscope (CLSM)) were observed. The deposition of 3YSZ and LS2 coatings changed the physicochemical properties of the Ti. Both coatings were biocompatible, while Ti-3YSZ demonstrated the most significant cell area of 2630 μm2 (p ≤ 0.05) and the significantly highest, 66.75 ± 4.91, focal adhesions (FAs) per cell after 24 h (p ≤ 0.05). By contrast, PEEK and PMMA demonstrated the highest roughness and WCA and the lowest results for cellular response. Thus, Ti-3YSZ and Ti-LS2 surfaces might be promising for biomedical applications.

An In Vivo Study in Rat Femurs of Bioactive Silicate Coatings on Titanium Dental Implants.

Silica-based ceramics have been proposed for coating purposes to enhance dental and orthopedic titanium (Ti) implant bioactivity. The aim of this study was to investigate the influence of sphene-based bioceramic (CaO.TiO2.SiO2) coatings on implant osseointegration in vivo. Sphene coatings were obtained from preceramic polymers and nano-sized active precursors and deposited by an automatic airbrush. Twenty customized Ti implants, ten sphene-coated and ten uncoated rough implants were implanted into the proximal femurs of ten Sprague-Dawley rats. Overall, cortical and cancellous bone-to-implant contact (BIC) were determined using micro-computed tomography (micro-CT) at 14 and 28 days. Moreover, peri-implant bone healing was histologically and histomorphometrically evaluated. The white blood cell count in the synovial fluid of the knee joints, if present, was also assessed. No difference in the BIC values was observed between the sphene-coated and uncoated implants, overall and in the two bone compartments (p > 0.05). Delamination of the coating occurred in three cases. Consistently with micro-CT data, the histological evaluation revealed no differences between the two groups. In addition, no synovial fluid could be collected on the test side, thus confirming sphene biocompatibility. In conclusion, sphene coating was found to be a suitable material for biomedical applications. Further studies are needed to improve coating adhesion to the implants.

Surface Modification of Titanium by Hydroxyapatite/CaSiO3/Chitosan Porous Bioceramic Coating

Surface Modification of Titanium by Hydroxyapatite/CaSiO3/Chitosan Porous Bioceramic Coating

Nano/Micro Hierarchical Bioceramic Coatings for Bone Implant Surface Treatments.

Bone implants with surface modifications that promote the physiological activities of osteoblasts are the first step for osseointegration in bone repair. Hydroxyapatite is the main inorganic component in mammal bones and teeth, and nanoscaled hydroxyapatite promotes the adhesion of osteoblastic cells. In this study, we created a nano/micro hierarchical structure using micro-arc oxidation coatings and hydrothermal treatments at 150 °C, 175 °C, and 200 °C for 2, 6, 12, and 24 h. After undergoing hydrothermal treatment for 24 h, CaTiO3 began forming regular-shaped crystals at the surface at 175 °C. In order to decrease the CaTiO3 formations and increase the apatite fabrication, a shorter time of hydrothermal treatment was required at 175 °C. There was still surface damage on samples treated for 6 h at 175 °C; however, the nano/micro hierarchical structures were formed in 2 h at 175 °C. The normalized alkaline phosphatase (ALP) activities of the MC3T3-E1 cells with micro-arc oxidation (MAO) coatings and nano/micro hierarchical bioceramics coatings were 4.51 ± 0.26 and 7.36 ± 0.51 μmol p-NP/mg protein (*** P value of <0.001), respectively. The MC3T3-E1 cells with coatings showed highly statistically significant results in terms of the ALP activity. This proposed nano/micro hierarchical structure promoted cell proliferation and osteogenic differentiation of the osteoblast MC3T3-E1 cells. This study realized a promising nano system for osseointegration via bone implant surface treatments, which can promote the physiological activities of osteoblasts.

Novel Synthesis of Core-Shell Biomaterials from Polymeric Filaments with a Bioceramic Coating for Biomedical Applications

Bone tissue engineering is constantly in need of new material development with improved biocompatibility or mechanical features closer to those of natural bone. Other important factors are the sustainability, cost, and origin of the natural precursors involved in the technological process. This study focused on two widely used polymers in tissue engineering, namely polylactic acid (PLA) and thermoplastic polyurethane (TPU), as well as bovine-bone-derived hydroxyapatite (HA) for the manufacturing of core-shell structures. In order to embed the ceramic particles on the polymeric filaments surface, the materials were introduced in an electrical oven at various temperatures and exposure times and under various pressing forces. The obtained core-shell structures were characterized in terms of morphology and composition, and a pull-out test was used to demonstrate the particles adhesion on the polymeric filaments structure. Thermal properties (modulated temperature and exposure time) and the pressing force’s influence upon HA particles’ insertion degree were evaluated. More to the point, the form variation factor and the mass variation led to the optimal technological parameters for the synthesis of core-shell materials for prospect additive manufacturing and regenerative medicine applications.

Surface Design Using Laser Rapid Manufacturing for Ti64-Hopeite Orthopedic Implants

Although hopeite bioceramic coatings have already proven effective for achieving better osseointegration and antibacterial character, but the detachment of hopeite coatings during implanting of coated implants can negatively affect the hopeite bioactivity in the physiological environment. To overcome this issue, the present research work proposes a new process route of laser rapid manufacturing (LRM) for depositing hopeite coatings with the metallurgical bond. Microstructure, phase composition, microhardness, antibacterial efficacy, and bioactivity were evaluated using scanning electron microscope, X-ray diffraction, Vickers microhardness tester, fluorescence-activated cell sorting technique, simulated body fluid immersion test respectively. The promising results obtained from these characterizations and testing establishes a new process route LRM as an effective alternative to deposit multifunctional hopeite coatings on metallic prosthetic–orthopedic implants.

Investigation of the Conditions of Production of Bioceramic Coatings Based on Strontium-Substituted Tricalcium Phosphate with Predictable Mechanical and Structural-Morphological Characteristics

We performed a complex experimental investigation of plasma bioceramic coatings based on strontiumsubstituted tricalcium phosphate powder obtained by using different technological modes of spraying. We establish the technological conditions of the process of deposition of the coatings guaranteeing the production of adhesion-resistant coatings with a well-developed microscopic surface topography and hydrophilic properties.

Effect of pore-forming agent quantity on pore structure, phase composition, micro-hardness of gradient bioceramic coatings under optimal laser process parameters

Titanium-based gradient bioceramic coating fabricated by laser cladding has been studied due to its excellent comprehensive performance and potential value in biomaterials. However, pore sizes of the coating prepared using traditional laser cladding technique are typically too small which can reduce its osteogenesis performance. To address this issue, a porous gradient bioceramic coating is successfully prepared on a titanium alloy surface by adding a pore-forming agent to the coating powder with subsequent laser cladding process. The bioceramic coating prepared with the optimized processing conditions (output power P = 1.8 kW, scanning speed V = 240 mm/min, and spot diameter D = 4 mm) exhibits a flat surface that comprises of a uniform enamel microstructure. The coating is metallurgically bonded to the substrate with a low number of microcracks. When the amount of pore-forming agent A = 2.5 wt%, the distribution of pores in coating becomes more uniform. When A = 2.5 to 10 wt%, the most probable pore size is 2.5 μm. It is shown that pore-forming agent quantity A = 2.5 wt% has a significant advantage in producing more large-sized pores in the coating. The number of pores in coating shows a trend of decreasing first, then increasing, and then decreasing. The coating phase consists of HA, β-TCP, TiO2, CaTiO3, etc., which is consistent with the coating material without pore-forming agent. In general, microhardness gradually decreases with increasing pore-forming agent quantity. The maximum microhardness values of coatings with and without pore-forming agent are 976 HV0.2 and 2086 HV0.2, respectively. Therefore, with the addition of a suitable amount of pore-forming agent, a porous bioceramic coating can be fabricated by an optimized laser cladding technique. This porous morphology will be beneficial for improving the osteogenic properties of the coating.

Solubility, Mechanical and Biological Properties of Fluoridated Hydroxyapatite/Calcium Silicate Gradient Coatings for Orthopedic and Dental Applications

Functionally graded fluoridated hydroxyapatite/calcium silicate (FHA/CS) bioceramic coatings (FGCs) were designed and prepared using suspension plasma spraying technology in order to improve the chemical stability and bonding strength of single HA coatings. Phase compositions, microstructures, solubility, mechanical and biological properties of the FGCs were investigated. The results showed that the coatings had a continuous compositional gradient along the cross section without a distinguishable interface. The amount of CS gradually decreased, and the amount of FHA gradually increased from the substrate to the FGC surface. The bonding strength of the FGCs was improved due to the design of gradient structure and reached 29.2 MPa, which was 20% higher than that of the pure FHA coating. Dissolution behavior of the FGCs was evaluated by immersing samples in citric acid-modified PBS solution (pH = 4.0), and the solubility resistance of the FGCs was improved due to the presence of the surface FHA layer resulting in a lower Ca2+ ion and Si4+ ion release. In addition, the FGCs showed a similar apatite-forming ability and cellular response in vitro to FHA coatings, suggesting a potential competitive use for coating bone implants.

Preparation of Laser-Modified Ti-15Mo Surfaces With Multiphase Calcium Phosphate Coatings

Multiphasic bioceramic scaffolds has been enhanced for dental and orthopedic applications. In this perspective, the laser surface texturing of metallic surfaces combined to bioactive calcium phosphate coatings have shown to be promising and economically feasible for biomaterial clinical applications. Ti-15Mo alloy samples were irradiated by pulsed Yb: YAG laser beam. The formation of HA and other calcium phosphates phases by biomimetic method should occur in the presence of Ca2+, PO43-, Mg2+, HCO3-, K+ and Na+. The modified surfaces were submitted to thermal treatment at 380 and 580°C. The results showed the processes of fusion and fast solidification from the laser beam irradiation, inducing the formation of stoichiometric α-Ti, TiO2 and non-stoichiometric titanium oxides, Ti3O and Ti6O with different oxide percentages depending on applied fluency (fluency of 0.023, 0.033, 0.040 and 0.048 J/mm2). The morphological and physicochemical properties have indicated the formation of a multiphase bioceramic coatings. It was observed the formation of amorphous calcium phosphate (ACP), octacalcium phosphate (OCP), and magnesium phosphate (Mg3(PO4)2) phases at 380°C, whereas β-TCP (tricalcium phosphate), OCP, and substituted β-TCP with Ca2,589Mg0,41(PO4)2 were obtained at 580°C. Therefore, the multiphasic bioceramic modified Ti-15Mo surface could enhance osteointegration for bone regeneration.

In-vitro performance of reinforced hydroxyapatite coatings deposited using vacuum plasma spray technique on Ti-6Al-4V

In this investigation the basic in-vitro assessment of substrate (Ti-6Al-4V), as-deposited and heat treated reinforced HA coatings has been performed to evaluate the biocompatible conduct of these bio-ceramic coatings. Briefly adherent fibroblast cell lines NIN3T3 and non-adherent human peripheral blood monocyte cells (hPBMCs) were utilized to survey the surface biocompatibility utilizing standard MTT, trypan blue tests while their reactive oxygen species profiling was done to comprehend the potential pressure that may hamper the human cell working. The outcomes demonstrated that the as-deposited and heat treated coatings displayed incredible cell reasonability for hPBMCs and NIN3T3 cells in contrast with bare substrates. Comparative results were observed for trypan blue dye exclusion assay. Besides, oxygen free radical levels demonstrated that there is no change in reactive oxygen species (ROS) levels in cells cultured on heat treated coatings. This suggests the materials utilized in coatings are not cytotoxic in nature and the phenomenon was true both for cell lines just as human primary cells. By and large natural assessment showed that coatings are protected to human cells in essential conditions.

Study on microstructure, microhardness, bioactivity, and biocompatibility of La2 O3 -containing bioceramic coating doping SiO2 fabricated by laser cladding.

To solve the lack of strength of calcium phosphate ceramic coatings in load-bearing applications, gradient Ca-P bioceramic coatings doped with La2 O3 and SiO2 are fabricated by laser cladding on Ti-6Al-4 V. The effect of SiO2 on microstructure, microhardness, bioactivity, and biocompatibility of coatings was investigated. The experimental results illustrate that the coating doped with La2 O3 and SiO2 has excellent metallurgical bonding. The XRD analysis confirms that the amount of hydroxyapatite and tricalcium phosphate in the coating reached maximum when doping amount of SiO2 is 10 wt %. SiO2 -doped coatings show a significantly higher bone-like apatite precipitation after immersion in SBF than that of other coatings. in vitro experiment also shows that coating with 10 wt % SiO2 is more suitable for the attachment and proliferation of MG63 cells, indicating that coating with 10 wt % SiO2 exhibits best bioactivity and biocompatibility. These results suggest that the addition of SiO2 improves the bonding strength, bioactivity, and biocompatibility of coatings.

Biological adhesion and electrochemical behavior of Ag-ZrO2 bioceramic coatings for biomedical applications

Recently, surface tailoring of the metallic implant has taken considerable attention to enhance the longevity of implants. In this study, two different concentrations of silver (Ag) with zirconia (ZrO2) were deposited onto titanium (Ti) substrates using DC magnetron sputtering for both orthopedic and dental implants application. Thickness, surface morphology with elemental composition, functional group, and adhesion of the coatings were characterized by X–ray diffraction (XRD), stylus profilometer, field-emission scanning electron microscopy/energy-dispersive X-ray spectroscopy (FESEM/EDAX), Fourier transform infrared spectroscopy (FTIR) and nano-scratch indentor, respectively. Monoclinic phase of ZrO2 and cubic phase of Ag were confirmed with XRD. Nanostructured grains were obtained by FESEM analysis with the thickness of ∼300 nm, ∼700 nm and ∼800 nm for ZrO2, ZrO2–Ag and ZrO2–Ag(1) (Herein, ZrO2–Ag (low conc.) and ZrO2–Ag(1) (high conc.) coatings measured by profilometer. The in vitro bacterial adhesion was performed for as prepared ZrO2, ZrO2–Ag and ZrO2–Ag(1) coatings against E.coli, and Streptococcus sp. Adhesion study exhibits better performance for Ag containing ZrO2 rather than ZrO2 coated and uncoated Ti. Adhesion of platelet on the coated and uncoated Ti revealed that activated platelets are present in ZrO2–Ag(1) coated Ti. ZrO2 and ZrO2–Ag coated Ti showed enhanced fibroblast cell attachment and proliferation than uncoated Ti but not in ZrO2–Ag(1) coated Ti surface. Electrochemical impedance spectroscopy (EIS) results revealed superior corrosion resistance behavior for all the coatings than uncoated Ti in ABP electrolyte. The results stated those tailored Ti surfaces were certainly used to enhance the durability of the implant for biomedical applications.