Search

Hydroxyapatite (HA) coatings on metallic implants have been extensively used in orthopedic applications to improve tissue-implant interactions, enhance their biocompatibility, and enhance their functionality. However, the expensive synthetic HA is the most widely used bioceramic for implant coatings, leading to high implants costs. Hence, this research explored the potential of an inexpensive biogenic HA derived from fish scales and FsHA/yttria-stabilized zirconia (YSZ) bioceramic coatings on a Ti–6Al–4V alloy as an alternative to synthetic HA coatings. The FsHA/YSZ powders and the coatings were examined with X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray (SEM/EDX), and the surface roughness, microhardness, corrosion resistance, bioactivity, and in vitro cytotoxicity of the coatings were also determined. The morphological powder analysis revealed particles with a slightly irregular morphology and a fine spherical morphology, while the coating microstructure analysis revealed a fine lamellar morphology, with partially melted and unmelted FsHA particles, and fine microcracks along with evenly dispersed ZrO2 particles. The surface roughness of the FsHA coating increased by 87.5% compared with the uncoated substrate, and the addition of YSZ significantly reduced this value. A 35.5% increase in hardness was obtained in the FsHA + 20 wt.% YSZ coating, and the FsHA coating showed a 43.2% reduction in the corrosion rate compared with the uncoated substrate; a further 73% reduction was observed with the addition of YSZ. The microstructure of the coatings after 14 days of immersion in simulated body fluid (SBF) revealed enlarged cracks and delaminated segments with well-grown apatite spherulite layers on the whole surface of the coatings, while in vitro cytotoxicity analysis showed a good cell viability of 95% at the highest concentration of the specimen.

This paper reports the unusual ion sorption of zinc ions to the structure of solution-precursor plasma-sprayed hydroxyapatite coatings studied via X-ray photoelectron and Raman spectroscopy techniq...

Application of artificial neural networks for optimization of plasma spraying parameters was considered. Artificial neural networks were used to select realistic parameters of titanium and hydroxyapatite powder coating of titanium products. For titanium coatings, the optimal arc current was found to be 380-450 A; optimal spraying distance, 100-150 mm; optimal titanium powder dispersity, 40-90 μm. Similar optimal ranges were obtained for hydroxyapatite coatings. The goal of the optimization wais to maximize the coating adhesion to the substrate and to improve its porosity.

Hydroxyapatite (HA) coated carbon/carbon composites (CC) is a potential material for orthopedic application because of the combination of good biocompatibility and mechanical properties. In this work, we synthesize a tree-planting interface which is composed of holes formed by micro-oxidized CC substrates and carbon nanotubes (CNTs) to achieve a high bonding strength of HA coating. The holes include annular gaps between carbon fiber and pyrolytic carbon, as well as irregular holes formed by oxidized pyrolytic carbon. The CNTs can grow inside the holes and extend into the HA coating. As a result, the bonding strength of HA coating with tree-planting interface achieves 11.14 ± 0.78 MPa. It increases by 181.3% comparing with the HA coating on CC without interface (3.96 ± 0.30 MPa). The in-vitro bioactivity evaluated by the response of mesenchymal stem cells (MSCs) shows promotions of cell proliferation and cell activity with increasing culture time. After applied with tree-planting interface, the HA coating with strong bonding and good bioactivity may be applied in orthopedic field in the future.

Composite scaffolds obtained by the combination of biodegradable porous scaffolds and hydroxyapatite with bone regeneration potential are feasible materials for bone tissue engineering. However, most composite scaffolds have been fabricated by complicated procedures or under thermally harsh conditions. We have previously demonstrated that hydroxyapatite coating onto various substrates under a thermally mild condition was achieved by erbium-doped yttrium aluminum garnet (Er: YAG) pulsed laser deposition (PLD). The purpose of this study was to prepare a polycaprolactone (PCL) porous scaffold coated with the hydroxyapatite by the Er: YAG-PLD method. Hydroxyapatite coating by the Er: YAG-PLD method was confirmed by morphology, crystallographic analysis, and surface chemical characterization studies. When cultured on PCL porous scaffold coated with hydroxyapatite, rat bone marrow-derived mesenchymal stem cells adhered, spread, and proliferated well. The micro-CT and staining analyses after the implantation of scaffold into the critical-sized calvaria bone defect in rats indicate that PCL porous scaffold coated with hydroxyapatite demonstrates accelerated and widespread bone formation. In conclusion, PCL porous scaffold coated with hydroxyapatite obtained by the Er: YAG-PLD method is a promising material in bone tissue engineering.

Objectives: Titanium implants are regarded as a promising treatment modality for replacing missing teeth. Osteointegration and antibacterial properties are both desirable characteristics for titanium dental implants. The aim of this study was to create zinc (Zn)-, strontium (Sr)-, and magnesium (Mg)-multidoped hydroxyapatite (HAp) porous coatings, including HAp, Zn-doped HAp, and Zn-Sr-Mg-doped HAp, on titanium discs and implants using the vapor-induced pore-forming atmospheric plasma spraying (VIPF-APS) technique. Methods: The mRNA and protein levels of osteogenesis-associated genes such as collagen type I alpha 1 chain (COL1A1), decorin (DCN), osteoprotegerin (TNFRSF11B), and osteopontin (SPP1) were examined in human embryonic palatal mesenchymal cells. The antibacterial effects against periodontal bacteria, including Porphyromonas gingivalis and Prevotella nigrescens, were investigated. In addition, a rat animal model was used to evaluate new bone formation via histologic examination and micro-computed tomography (CT). Results: The ZnSrMg-HAp group was the most effective at inducing mRNA and protein expression of TNFRSF11B and SPP1 after 7 days of incubation, and TNFRSF11B and DCN after 11 days of incubation. In addition, both the ZnSrMg-HAp and Zn-HAp groups were effective against P. gingivalis and P. nigrescens. Furthermore, according to both in vitro studies and histologic findings, the ZnSrMg-HAp group exhibited the most prominent osteogenesis and concentrated bone growth along implant threads. Significance: A porous ZnSrMg-HAp coating using VIPF-APS could serve as a novel technique for coating titanium implant surfaces and preventing further bacterial infection.

Purpose The purpose of this study is to obtain an effective implant with porous structures on its surface, named porous-surfaced implant, which helps to improve the overall stability of the implant and promote the combination of implant and alveolar bone. Design/methodology/approach Porous-surfaced implants with a porosity of 16%, 21%and 32% were designed and the effect of porosity on the strength of the implant was analyzed by ABAQUS software. Porous-surfaced implants with different porosity were printed by selective laser melting and the surface morphology was observed. Animal experiments of implants with porous structures and coating were carried out in healthy beagle dogs. The experimental group was treated with hydroxyapatite coating and the control group was not treated. Bone volume (BV) and total volume (TV) of the implant surface of the experimental group and control group were calculated by Skyscan CTvol software. Findings With the increase of porosity of porous-surfaced implants, the neck stress of the porous-surfaced implants increased and their strength decreased. In addition, in animal vivo experiments, the ratio value of BV to TV of the porous-surfaced implants was between 55.38% and 79.86%, which was the largest when the porosity of porous-surfaced implants was 16%. The internal and surrounding bone formation content of porous-surfaced implants with hydroxyapatite coating was higher than porous-surfaced implants without coating. Originality/value The results of this study show that the pores on the surface of implants can be filled with the new bone and porous-surfaced implants with 16% porosity provide better space for the growth of new bone. The porous structures with hydroxyapatite coating are beneficial to the growth of new bone around implants. The results of this study are helpful to improve the overall stability of implants and to promote the combination of implant and alveolar bone.

Magnesium and its alloys are promising materials that have potential mainly in the field of transport (e.g. automobile industry) and medicine (e.g. orthopedic implants). Their disadvantage is poor corrosion resistance, which limits their wider use in practice. Therefore, surface treatment by various methods is performed in order to improve corrosion protection. The preparation of a superhydrophobic coating is an interesting approach because the hydrophobic coating minimizes contact of the corrosion medium with the magnesium substrate. In this work, the hydrothermally prepared hydroxyapatite coating on AZ31 magnesium alloy was superhydrophobized by myristic acid. The prepared coatings were characterized by determining contact angle and surface analysis using a scanning electron microscopy with energy dispersive spectroscopy and Fourier transformed infrared spectroscopy. The corrosion resistance of modified surfaces was examined by potenciodynamic polarization in 3.5 % NaCl.

The surface of titanium (Ti) dental implants must be modified to improve their applicability, owing to the biological inertness of Ti. This study aims to use sandblasting as a pretreatment method and prepare a hydroxyapatite (HA) coating on Ti to improve its biocompatibility and induce bone bonding and osteogenesis. In this paper, sandblasted Ti discs were coated with α-tricalcium phosphate (α-TCP) via Er:YAG pulsed laser deposition (Er:YAG-PLD). An HA coating was then obtained via the hydrothermal treatment of the discs at 90 °C for 10 h. The surface characteristics of the samples were evaluated by SEM, SPM, XPS, XRD, FTIR, and tensile tests. Rat bone marrow mesenchymal stem cells were seeded on the HA-coated discs to determine cellular responses in vitro. The surface characterization results indicated the successful transformation of the HA coating with a nanorod-like morphology, and its surface roughness increased. In vitro experiments revealed increased cell attachment on the HA-coated discs, as did the cell morphology of fluorescence staining and SEM analysis; in contrast, there was no increase in cell proliferation. This study confirms that Er:YAG-PLD could be used as an implant surface-modification technique to prepare HA coatings with a nanorod-like morphology on Ti discs.

Excellent osseointegration of biomaterial is very important for the stability of dental implants in clinical field. Much has been learned about this concept and significant improvements on the design and surface modification of implants have been done in the implant dentistry.

Magnesium (Mg) alloys are receiving increasing attention as biodegradable implant materials in recent years. However, their low corrosion resistance and fast degradation in the physiological environment remain challenges for a widespread application. Hydroxyapatite (HA) coating on Mg alloys can enhance their corrosion resistance, biocompatibility, and bioactivity of the Mg alloy substrates since the compositions of HA are similar to those of the hard tissue of natural bone. This review analyzes the challenges of Mg alloys for biomedical applications, the fundamental requirements for biodegradable metals, and the corrosion mechanisms of Mg alloys in the physiological environment. The benefits of HA coatings on Mg alloys, the most commonly used surface coating techniques and their advantages and limitations, and the in vitro and in vivo performance of Mg alloys with and without surface coatings are comprehensively elucidated. Multistep processes such as alkali treatment and then HA coating by electrochemical deposition on Mg alloys appear to be necessary to achieve a satisfactory surface coating on Mg alloys, which has been demonstrated to have the potential to improve the degrading behavior, bioactivity and biocompatibility. Multifunctional coatings are most effective in achieving safe and bioactive Mg alloy surfaces for promising biodegradable implant applications.

Hydroxyapatite (HA) coating was deposited on commercially pure Ti to improve its biocompatibility as a biomedical implant material. The HA layer was deposited by the electrophoretic deposition (EPD) method. The processing parameters controlled the HA structure. In this research, the applied voltage was varied 20, 30, and 40 V to optimize a free-crack layer. The current output during EPD at 20 V was in the order of 10-5 A/cm2. A higher current density in the order of 10-4 A/cm2 was obtained at 30 and 40 V. The coating formed at 20 V was relatively free of crack. A high number of cracks began to observe in the layer formed at 30 V, while only a few cracks were revealed on the layer formed at 40 V. The average thickness of the HA layer increased slightly with applied voltage. The thickness was approximately 40±5 µm, as observed by an optical microscope. The optimum voltage to produce a thick HA layer with a small number of cracks was at 40 V.

Metallic implants are extensively used to treat a spectrum of orthopaedic related disorders. Among the metals, titanium and its alloys are considered most excellent and indispensable material for the production of orthopaedic implants regarding their sterling mechanical properties and exceptional biocompatibility. Recently, rapid progress in developing non-toxic titanium-based alloys with modulus similar to that of human bone has inspired researchers globally. Thus, many studies have focused on titanium alloys, their heat treatment processes and several processing technologies. Additive manufacturing has been designed to enhance their mechanical properties tailored towards biomedical applications. Inarguably, the need to further improve on the implant’s biocompatibility with bodily environment for optimum service life is of great importance. Hence, hydroxyapatite coating provides an improvement as demonstrated by in vitro as well as in vivo studies. The present article critically reviews, based on recent scientific literatures, the progress made thus far in the development of titanium-based alloys, additive manufacturing processes and their heat and surface treatments tailored towards biomedical applications.

Dogs underwent high-frequency automated tibia lengthening with the Ilizarov apparatus over a 1.8-mm hydroxyapatite-coated intramedullary titanium wire. Daily distraction was 3.0 mm with a fraction of 0.125 mm/h and continued ten days. The regenerate was well vascularized, had zonal structure and was of normal or hyperplastic type to the end of distraction. Osteogenesis was fast and complete. The wire served for both mechanical and biological reinforcement of the bone callus and provided reduction of external fixation time. Mean consolidation time with the apparatus on the limb was 13.83±4.02 days. Overall, external fixation index was 10.5 days/cm and 4.8 days/cm in the consolidation phase.

This study aims to investigate the effect of the electrophoretic deposition process (EPD) of natural HA (extracted from bovine bones) with various particle size on Ti-29Nb-13Ta-4.6Zr (TNTZ) coating surfaces. HA particles were refined from bovine bone powders using planetary ball mill and then sieving to separate the particle based on its size. The maximum size according to sieving mesh size is #25 µm, #63 µm and #125 µm. The coating process was conducted by using EPD apparatus with voltage and time process 10V and 5 minutes, respectively, for each sample. The coating layer morphology was observed with Stereo Microscopy, Scanning Electron Microscopy (SEM) and the thickness was measured with Thickness Gauge. The result shows that the size of the particle determines the coating layer characteristics. The best of HA coating quality according to the implant coating standard is obtained for the 25 µm particle size with the surface coverage is 99%. The thickness is 121 µm and the ratio of chemical composition Calcium and Phosphor Ca/P) is 1,49%. These may be concluded that, on the point of view physical characteristics, natural HA from bovine bone has potential enough as a coating layer to improve the bioactivity implant for biomedical application. However, the mechanical characteristic of the layer is still needed to determine the strength of coating layer for avoiding delamination during application.

Hydroxyapatite (HA) is potentially used as a coating material for titanium alloys to improve their bioactivity and then enhancing the osseointegration characteristic of metal implants for orthopedic application. Electrophoretic Deposition (EPD), one of the coating methods that is widely applied for coating metal because of its simplicity and relatively low cost, is chosen for coating metal implants. HA coating layer quality can be controlled by adjusting applied voltages and coating time of the EPD process. However, the optimum voltage and exposing time has not yet been known for new type titanium implant such as Ti-12Cr and TNTZ. This work is, therefore, focusing on the effect of applied voltage and coating time on the mass growth, HA coating thickness, and surface coverage that can be produced on the surfaces of both alloys, and also on the conventional titanium alloy, Ti6Al4V, for comparison. The result of this work showed that there is a significant influence of the titanium alloy type on the HA layer performances. However, it is necessary to choose a suitable voltage and to expose time for producing a sufficient coating layer that meets the standard of orthopedic implants.

Aims Biofilm formation is intrinsic to prosthetic joint infection (PJI). In the current study, we evaluated the effects of silver-containing hydroxyapatite (Ag-HA) coating and vancomycin (VCM) on methicillin-resistant Staphylococcus aureus (MRSA) biofilm formation. Methods Pure titanium discs (Ti discs), Ti discs coated with HA (HA discs), and 3% Ag-HA discs developed using a thermal spraying were inoculated with MRSA suspensions containing a mean in vitro 4.3 (SD 0.8) x 106 or 43.0 (SD 8.4) x 105 colony-forming units (CFUs). Immediately after MRSA inoculation, sterile phosphate-buffered saline or VCM (20 µg/ml) was added, and the discs were incubated for 24 hours at 37°C. Viable cell counting, 3D confocal laser scanning microscopy with Airyscan, and scanning electron microscopy were then performed. HA discs and Ag HA discs were implanted subcutaneously in vivo in the dorsum of rats, and MRSA suspensions containing a mean in vivo 7.2 (SD 0.4) x 106 or 72.0 (SD 4.2) x 105 CFUs were inoculated on the discs. VCM was injected subcutaneously daily every 12 hours followed by viable cell counting. Results Biofilms that formed on HA discs were thicker and larger than those on Ti discs, whereas those on Ag-HA discs were thinner and smaller than those on Ti discs. Viable bacterial counts in vivo revealed that Ag-HA combined with VCM was the most effective treatment. Conclusion Ag-HA with VCM has a potential synergistic effect in reducing MRSA biofilm formation and can thus be useful for preventing and treating PJI. Cite this article: Bone Joint Res. 2020;9(5):211–218.

Finite element analysis (FEA) has been proven to be a precise and applicable method for evaluating dental implant systems. This is because FEA allows for measurement of the stress distribution inside of the bone and various dental implant designs via simulation analysis during mastication where such measurements are impossible to perform in-vitro or in-vivo experiment. That is why the relationship between implant design and load distribution at the implant bone interface is a crucial issue to understand. This research study focuses on a static simulation and bonding strength for PLA/HA coating on V thread design of dental implant using three-dimensional finite element. The average masticatory muscle that involves in human biting such as X, Y and Z direction will be used to simulate force with load condition of 17.1N, 114.6N and 23.4N respectively. Based on result obtained, the coated dental implant model is more compatible than uncoated model due to lower maximum stress which is reduce about 16%. The coated model also shows lower deformation and higher bonding strength. Outcomes from this research provide a better understanding of stress distribution characteristics that would be useful in order to improve design of dental implant thread and evaluation of the PLA/HA bonding strength applied.

Both tensile and shear adhesion strength tests were performed to evaluate interfacial strength between hydroxyapatite coatings on titanium alloy substrates subjected to anodization and heat treatment prior to deposition as well as post-deposition heat treatment. Results of the tensile adhesion strength tests were influenced by the size of the blasting media and the processing of pre- and post-heat treatments but not influenced by anodization. The finite element method (FEM) analysis of stress distribution during the shear adhesion strength test was also performed to evaluate the degree of stress singularity. The results show that the stress singularity parameters were dominant factors of stress distribution in the stress singularity fields, and they were also expected to influence the “essential” interfacial strength. In addition, the size of the blasting media had the same influence on the shear and tensile adhesion strength tests. This suggests the possibility of estimating tensile adhesion strength using the results of shear adhesion strength.

Composite materials with a biologically active coating are created. The morphology of a newly formed surface is studied by scanning electron microscopy, as well as the Brunauer–Emmett–Taylor method. The adhesive strength of the hydroxyapatite coating is determined by centrifugal separation. As a result of the studies, the most promising method of deposition, the best shape of the coating material and the optimal porosity of the titanium scaffold are established.

Titanium and its alloys are standard for orthopedic prosthetic devices, due to their good mechanical properties and biocompatibility. However, bioactivity on the implant surface needs to be improved to achieve an optimal osseointegration process. Metal implants are often coated by hydroxyapatite because they have a chemical composition and crystal structure similar to apatite in the human skeletal that suitable for bone reconstruction. The focus of this research is on surface treatment designed to promote better biological responses through hydroxyapatite layers. Also combining the acid etching treatment of Ti-6Al-4V and the electrophoretic coating process of the hydroxyapatite to obtain stronger mechanical interlocking interface. Hydrofluoric-Acid treatment conducted in various time. Then, coated with nanosized hydroxyapatite through electrophoretic deposition at 15V voltage for 10 minutes. Scanning Electron Microscopy and Contour measurements were performed to show the surface topography indicating the formation of surface contours with increasing surface roughness parameters in accordance with the time of the etching process. The contours on the surface of the substrate induce the mechanical interlocking of the surface so that the results of hydroxyapatite deposition optimal at the time of etching 5 minutes

Background. There are many strategies for modifying the surface of implants to create optimal conditions for the development of bone tissue. At the same time, the question of correlation of the effect of surface roughness or surface chemical composition on cell activity or osteogenesis processes remains open. Objective. The study of cellular mechanisms of osseointegration using cell cultures that occur after implantation of implants with a different type of alloy and the nature of their surface. Methods. To analyze the adhesion and cell proliferaiton, the resazurin reduction method was used, scanning electron microscopy was used to determine the distribution of cells on the sample surface and the type of cell interaction with surface. Results. Cell adhesion is observed in all studied groups, and the degree of cell adhesion is directly related to the presence of hydroxyapatite on the surface. A growing trend in the proliferation of osteoblasts is noted, while fibroblast proliferation slows down from the 3rd to the 7th day. At the same time, slow cell proliferation occurs on the surface of the implants without modification, and the percentage the reduction of resazurin does not exceed 23.5%. It should be noted that there is no difference between the types of alloys, which proves the predominance of the influence of surface topography on the proliferative activity of osteoblasts. Scanning electron microscopy on the 7th day revealed the presence of osteoblasts and fibroblasts in all studied samples. However, in the absence of hydroxyapatite, the cells are unevenly located on the surface of the sample, they are large in size and have long processes that do not have a clear orientation, and on the surface with hydroxyapatite coating there is a higher cell growth density, which predominantly has 2 processes and oriented in the same direction. Conclusion. The use of hydroxyapatite coating significantly increases the ability of cells to adhere to the surface of the implant. The presence of calcium and phosphorus mainly stimulates the proliferation of osteoblastic dipheron cells and almost does not affect the ability of fibroblasts to proliferate., Актуальность. Существует множество стратегий модификаций поверхности имплантатов для создания оптимальных условий для развития костной ткани. При этом остается открытым вопрос о корреляции влияния шероховатости или химического состава поверхности на активность клеток или процессы остеогенеза. Цель. Изучение клеточных механизмов остеоинтеграции с применением культур клеток, происходящих после вживления имплантатов с различным типом сплава и характером их поверхности. Методы. Для анализа адгезии и динамики роста клеток использовали метод редукции резазурина, а для определения распределения клеток на поверхности образца и типа взаимодействия клеток с поверхностью – метод растровой электронной микроскопии. Результаты. Адгезия клеток наблюдается во всех исследуемых группах, причем степень их адгезии имеет прямую связь с наличием на поверхности гидроксиапатита. Отмечается растущий тренд пролиферации остеобластов, в то время пролиферация фибробластов замедляется с 3-х по 7-е сутки. При этом на поверхности имплантатов без модификации происходит медленная пролиферация клеток, а процент роста редукции резазурина не превышает 23,5%. Следует заметить, что разница между типами сплавов отсутствует, что доказывает преобладание влияния топографии поверхности на пролиферативную активность остеобластов. Растровая электронная микроскопия на 7-е сутки выявила наличие остеобластов и фибробластов на всех исследуемых образцах. Однако при отсутствии гидроксиапатита клетки неравномерно расположены на поверхности образца, отличаются большими размерами и наличием длинных отростков, не имеющие четкой ориентации, а на поверхности с гидроксиапатитным покрытием отмечается более высокая плотность роста клеток, которые преимущественно имеют 2 отростка и ориентированные в одном направлении. Итог. Использование гидроксиапатитного покрытия значительно повышает способность клеток к адгезии на поверхности имплантата. Наличие кальция и фосфора преимущественно стимулирует пролиферацию клеток остеобластического диферона и почти не влияет на способность фибробластов к пролиферации., Актуальність. Існує безліч стратегій модифікацій поверхні імплантатів для створення оптимальних умов для розвитку кісткової тканини. При цьому залишається відкритим питання щодо кореляції впливу шорсткості чи хімічного складу поверхні на активність клітин чи процеси остеогенезу. Мета. Вивчення клітинних механізмів остеоінтеграції із застосуванням культур клітин, що відбуваються після вживляння імплантатів з різним типом сплаву та характером їх поверхні. Методи. Для аналізу адгезії та динаміки росту клітин використовували метод редукції резазурину, а для визначення розподілу клітин на поверхні зразка та типу взаємодії клітин з поверхнею - метод растрової електронної мікроскопії. Результати. Адгезія клітин спостерігається у всіх досліджуваних групах, при чому ступінь їх адгезії має прямий зв’язок з наявністю на поверхні гідроксиапатиту. Відзначається зростаючий тренд проліферації остеобластів, в той час проліферація фібробластів уповільнюється з 3-ї до 7-ї доби. При цьому на поверхні імплантатів без модифікації відбувається повільна проліферація клітин, а відсоток зростання редукції резазурину не перевищує 23,5%. Слід зауважити, що різниця між типами сплавів відсутня, що доводить переважання впливу топографії поверхні на проліферативну активність остеобластів. Растрова електронна мікроскопія на 7-му добу виявила наявність остеобластів та фібробластів на всіх досліджуваних зразках. Проте за відсутності гідроксиапатиту клітини нерівномірно розташовані на поверхні зразка, відрізняються більшими розмірами та наявністю довгих відростків, які не мають чіткої орієнтації, а на поверхні з гідроксиапатитним покриттям відмічається значно вища щільність росту клітин, які переважно мають 2 відростки, орієнтовані в одному напрямі. Підсумок. Використання гідроксиапатитного покриття значно підвищує здатність клітин до адгезії на поверхні імплантату. Наявність кальцію та фосфору переважно стимулює проліферацію клітин остеобластичного диферону та майже не впливає на здатність фібробластів до проліферації.

Hydroxyapatite (HA) was obtained from eggshells using selective thermal treatment. The properties like mechanical strength, biocompatibility and adhesion of hydroxyapatite were enhanced by adding titanium oxide (TiO2) and aluminum oxide (Al2O3) in two different compositions (HA-10TiO2-10Al2O3 (H10T10A) and HA-20TiO2-20Al2O3 (H20T20A)). Mechanical performance of the detonation sprayed H10T10A and H20T20A hybrid ceramic powders on AISI 304L SS steel were estimated by pin-on-disc apparatus. A load of 110 N was applied constantly over the pin which slides a linear distance of 2700 m at a linear velocity of 1 m/s at atmospheric temperature. The present investigation shows that the specific wear rate of bare AISI 304L SS was 8.23 × 10−5 mm3/N-m, while those of H20T20A and H10T10A coatings were 0.402 and 0.844 × 10−5 mm3/N-m respectively. The coatings and coating powders were characterized by SEM, XRD and FT-IR, XRD techniques respectively. The results showed that H20T20A coating has higher wear resistance in comparison to HA10T10A.

In the current study, 10% zinc substituted hydroxyapatite coating was formed on titanium surface and subsequently phosphatidylethanolamine was incorporated into the coating to study the osteogenic and antibacterial behavior of the coated surface. X-ray diffraction analysis showed the formation of zinc substituted hydroxyapatite on titanium while energy dispersive X-ray spectrometry substantiated the coating to be calcium deficient. Phosphatidylethanolamine incorporated coating on titanium showed higher cell viability and antibacterial property as compared to the control. The superior cell activities on this surface may be attributed to the presence of phosphatidylethanolamine in the coating. Keywords: Phosphatidylethanolamine, Zinc, Hydroxyapatite, Titanium

Highlights • Septic arthritis of the hip joint is relatively uncommon in adults. • Ag-HA implants have not been used in two-stage total hip arthroplasty. • Ag-HA implants may be used in two-staged total hip arthroplasty., Introduction Septic arthritis of the hip joint in adults is a rare and potentially devasting disease. To the best of our knowledge, there have been no reports of two-stage total hip arthroplasty (THA) for the treatment of septic arthritis of the hip joint with a cementless hip implant that has antibacterial properties. Presentation of case We present a case of two-stage THA with a thermal-sprayed silver oxide-containing hydroxyapatite coating (Ag-HA) implant to treat septic arthritis of the hip joint with hip osteoarthritis in an 80-year-old woman. There was no complication or recurrence at 28 months follow-up after 2nd-stage operation. Discussion Ag-HA implants were found to have antibacterial activity within the subcutaneous tissues and bone, osteoconductive properties, and no adverse reactions in vivo. Moreover, no adverse events due to silver were reported in a clinical or radiographic study. Conclusion To further reduce infection after two-staged THA for septic arthritis of the hip joint, antibacterial implants, such as an Ag-HA implant, may be used.

We study the influence of the voltage (100–180 V) of plasma-electrolytic oxidation on the formation of hydroxyapatite coatings on VT1-0 commercially pure titanium in alkaline electrolytes (hydroxyapatite + 1 M potassium hydroxide). We analyze the physical and chemical characteristics of hydroxyapatite coatings (phase composition, thickness, porosity, and surface roughness) and establish the conditions of formation of coatings for which the ratio Ca/P is close to the values typical of biological hydroxyapatite.

Titanium and its alloys are widely used in medical devices, orthopedic implants, dental implants, and device components of aerospace industries. It is attractive for having superior room and elevated temperature mechanical properties, corrosion resistance, fatigue resistance and low weight. However, titanium and its alloys are not fully applicable replacement in biomedical application. Suitable surface modification of titanium is needed in order to obtain Ti with improved properties. This paper deals with the optimization of the in-situ anodizing/anaphoretic electrodeposition process of hydrothermally synthesized hydroxyapatite (HAp) on Ti substrate for subsequent obtaining of HAp/TiO2 composite coatings without multi-stage pre-treatment and post-treatment of titanium and oxidized titanium surface. Coatings were prepared at constant voltage of 60 V and deposition time of 1 min. The morphology of coatings was investigated using optical microscope and field emission scanning electron microscope. Fourier transform infrared spectroscopy measurements were also performed. The coating with optimal properties was obtained by deposition from suspension containing 1.0 M NaOH.

A new preparation method of hydroxyapatite coating was proposed for the conservation of gypsum crust on historic limestones. by successive introduction of calcium and phosphorus sources into the crust by surface permeation. Due to the formation of hydroxyapatite coating, both surface protection and integral consolidation of the gypsum crust can be accomplished. The performances of the hydroxyapatite coating were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffractometry, water stability, capillary water uptake, color difference and adhesion strength test. The experimental results indicated that the hydroxyapatite coating would be a good solution for the conservation of the gypsified historic limestone surface.

Medical pure titanium (Ti) shows excellent chemical stability and mechanical properties in clinical uses, but its initial fixation with host bone, when implanted, is usually delayed owing to the bioinert Ti surface. In this study, we fabricate the hydroxyapatite (HA)-coated titanium by three steps reactions: (1) to form an activated O2− layer by immersing Ti substrate into an alkaline solution such as NaOH, (2) the O2− bonds with Ca2+ to form Ca–O–Ti bonding, in which O plays the part of bridge materials between Ca and Ti substrate and (3) the conversion of Ca–O–Ti samples to HA-coated Ti samples by immersion into Na2HPO4 2 M at 180 °C for 48 h using hydrothermal methods. The effect of different phosphate solutions (NaH2PO4 2 M and Na2HPO4 2 M solution) and hydrothermal treatment time (24 and 48 h) on the characteristic of hydroxyapatite coating titanium substrate is also investigated using the optical microscope, thin film XRD and SEM/EDX. The HA-coated Ti samples fabricated by immersion into Na2HPO4 2 M at 180 °C for 48 h show fiber HA covering Titan substrate with a diameter varying from 0.1 to 0.3 µm. These HA-coated Ti samples can be regarded as promising multifunctional biomaterials.

The wide application of magnesium alloys as biodegradable implant materials is limited because of their fast degradation rate. Hydroxyapatite (HA) coating can reduce the degradation rate of Mg alloys and improve the biological activity of Mg alloys, and has the ability of bone induction and bone conduction. The preparation of HA coating on the surface of degradable Mg alloys can improve the existing problems, to a certain extent. This paper reviewed different preparation methods of HA coatings on biodegradable Mg alloys, and their effects on magnesium alloys’ degradation, biocompatibility, and osteogenic properties. However, no coating prepared can meet the above requirements. There was a lack of systematic research on the degradation of coating samples in vivo, and the osteogenic performance. Therefore, future research can focus on combining existing coating preparation technology and complementary advantages to develop new coating preparation techniques, to obtain more balanced coatings. Second, further study on the metabolic mechanism of HA-coated Mg alloys in vivo can help to predict its degradation behavior, and finally achieve controllable degradation, and further promote the study of the osteogenic effect of HA-coated Mg alloys in vivo.

Prosthetic joint infection (PJI) is one of the most devastating complications that can occur following total hip and total knee arthroplasty. Despite the remarkable advances that have been made in surgical techniques and implant technology, the incidence of PJI has remained largely unchanged over the past two decades. One approach that has been described in the literature to minimize the risk of PJI has been the use of silver-coated prostheses. Silver has been reported to have antimicrobial properties when added to a variety of orthopaedic materials including bone cement, hydroxyapatite coatings and wound dressings. Silver is also being increasingly used as a surface coating for endoprostheses used for reconstruction around the hip and the knee with the specific aim of reducing the incidence of prosthetic joint infection. Despite the increasing adoption of this technology, the use of silver coatings remains controversial. The optimal method for preparation and the thickness of the coating, as well as the mechanism(s) of action in reducing the incidence of PJI, are unclear. The issue of silver toxicity is also an important consideration. This paper provides an overview of the use of silver coatings in reconstructive orthopaedics, as well as the types available and techniques used to coat endoprostheses. We also review the basic science as well as the clinical applications of silver coatings in the prevention of PJIs.

Artificial material such as stainless steel (SS) is widely used for orthopaedic applications owing to its superior properties, ease of fabrication and lower cost. However, in the body environment, stainless steel can leach toxic elements such as nickel and chromium. To prevent this, a hydroxyapatite (HAp) coating having chemical characteristics very similar to the human bone was deposited on a medical-grade UNS S31254 austenitic stainless steel by a Low-velocity oxy-fuel spray gun (LVOF). The coating was characterised by using a field emission scanning electron microscope (FESEM), X-ray diffractometer (XRD) and Fourier transform infrared spectroscope (FTIR). The adhesion strength, microhardness and corrosion behaviour were studied using the Tensometre, Vickers microhardness tester and potentiodynamic polarisation with electrochemical impedance spectroscope. The bacterial adhesion and bioactivity of the coating were also evaluated. The LVOF sprayed HAp coating has shown better corrosion resistance, higher bioactivity and higher hardness than the uncoated steel. The presence of tricalcium phosphate, octa-calcium phosphate (OCP) and tetra-calcium phosphate (TTCP) was found in the coating. LVOF sprayed HAp coating is also found suitable in lowering the bacterial adhesion on the steel substrate.

Few reports have evaluated the use of hydroxyapatite (HA) coating in SL-MIA-type stems in total hip arthroplasty (THA). Here, we compared early femoral bone remodeling after total hip arthroplasty using the SL-PLUS MIA stem with and without hydroxyapatite coating. From February 2012 to March 2017, 132 patients (150 hips) (HA group: 48 patients [52 hips], non-HA group: 84 patients [98 hips]) underwent THA with an SL-PLUS MIA stem. The mean follow-up duration was 3.7 years (standard deviation 1.2, range: 1.0–6.1). The Harris Hip Score (HHS), postoperative bleeding volume measurements and plain radiographs were used for clinical and radiological follow-up evaluations. Peri-prosthetic bone mineral density changes were measured by dual-energy X-ray absorptiometry. At 1 year, the HHS improved from 44.4 points preoperatively to 89.2 points postoperatively and from 44.5 points to 89.7 points in the HA and non-HA groups, respectively. At 1 year postoperatively, subsidence (≧ 3 mm) occurred in 0% and 8.2% of the HA and non-HA groups, respectively. Stress shielding (≧ Grade 3) occurred in 0% and 6% of the HA and non-HA groups, respectively. The radiolucent line was significantly smaller in the HA than in the non-HA group. There was no significant difference in the bone mineral density distribution in the two groups. Addition of HA to the SL-MIA stem can help enhance the initial fixation and early osseointegration. Further studies are required on the long-term effects of adding HA to reduce stress shielding of the proximal area of the stem.

Aluminium-free Mg–4Zn–4Sn–0.6Ca–0.5Mn alloys, with similar mechanical properties to natural bone, were produced and used as substrates for electrophoretic deposition (EPD) of hydroxyapatite (HA) po...

The lack of bioactivity of titanium (Ti) is one of the main drawbacks for its application in biomedical implants since it can considerable reduce its osseointegration capacities. One strategy to overcome this limitation is the coating of Ti with hydroxyapatite (HA), which presents similar chemical composition than bone. Nonetheless, most of the strategies currently used generate a non-stable coating and may produce the formation of amorphous phases when high temperatures are used. Herein, we proposed to generate a Ti-HA composite coating on Ti surface to improve the stability of the bioactive coating. The coating was produced by cold gas spraying, which uses relatively low temperatures, and compared to a Ti coating. The coating was thoroughly characterized in terms of morphology, roughness, porosity and phase composition. In addition, the coating was mechanically characterized using a tensile loading machine. Finally, biological response was evaluated after seeding SaOS-2 osteoblasts and measuring cell adhesion, proliferation and differentiation. The novel Ti-HA coating presented high porosity and high adhesion and bond strengths. No change in HA phases was observed after coating formation. Moreover, osteoblast-like cells adhered, proliferated and differentiated on Ti-HA coated surfaces suggesting that the novel coating might be a good candidate for biomedical applications. info:eu-repo/semantics/acceptedVersion

The goal of the present contribution is to show what is the effect of Ag addition on in vitro bioactivity and degradation characteristics of hydroxyapatite (HAP) in simulated body fluid (SBF), Dulbecco's Modified Eagle's medium (DMEM) and phosphate buffer solution (PBS) over a period of immersion at 37 ± 0.5 °C ranged from 1 to 21 days. Also, the corrosion investigations in all three media were carried out at 37 ± 0.5 °C. The results showed that the coatings behaviour is modulated with respect to the testing media and indicated that the Ag addition into hydroxyapatite has enhanced the general behaviour of HAP by either preventing and/or reducing dissolution of the HAP in SBF and DMEM solutions, while in PBS media the Ag addition contributed to a very slow degradation of hydroxyapatite. Thus, it can be said that the Ag addition into HAP enhances the overall chemical stability and behaviour in acellular media.

Plasma-sprayed hydroxyapatite (HA) coatings have been widely utilized in load-bearing titanium alloy implants. In this study, Mg, Sr co-substituted HA ((Mg, Sr)-HA) nano-scale powders have been synthesized, which are further used to prepare (Mg, Sr)-HA coatings on Ti-6Al-4V alloys in order to improve the biological functions. The average size of (Mg, Sr)-HA nano particles is ∼75 nm. The average bonding strength for (Mg, Sr)-HA coating and samples after heat treatment at 500 °C or 600 °C for 3 h are 26.17 ± 2.11 MPa, 36.07 ± 4.48 MPa and 37.07 ± 2.95 MPa, respectively. There is a significantly increase of bonding strength likely due to low residual stress after heated treatment. MC3T3-E1 cells show a high proliferation rate when cultured with (Mg, Sr)-HA coating extract compared to the normal culture medium, which also exhibit large extension and deposition of extracellular matrices when adhered on the coating surfaces. Thus, these (Mg, Sr)-HA coatings show high bonding strength and improved biological functions, which offer promising future applications in the fields of orthopedics and dentistry.

The treatment of osteochondral defects in joint cartilage remains challenging due to its limited repair capacity. This study presents a metallic osteochondral plug with hydroxyapatite (HA)-coated cap edges for improved implant-tissue contact. The hypothesis was that improved attachment prevents from synovial fluid-influx and thereby avoids osteolysis and resulting implant instability. In total, 24 female, adult sheep were randomized into three groups. All animals received an Episealer®-implant in the medial condyle of the right knee. The implants were coated with two different HA versions or uncoated (control group). After 12 weeks, the implant-tissue connections were analysed radiologically and histologically. In general, the groups with the coated cap edges showed a better quality of tissue connection to the implant. The occurrence of gaps between tissue and implant was more seldom, the binding of calcified and hyaline cartilage to the cap was significantly better than in the uncoated group. A histomorphometrically measured lower amount of void space in these groups compared to the group with the uncoated edges confirmed that. The hypothesis of a tighter cartilage bone contact was confirmed. The HA coating of the implant’s cap edges resulted in better adherence of cartilage to the implant, which was not previously reported. In conclusion, this led to a better contact between implant and cartilage as well as neighbouring bone. In clinical routine, joint fluid is aggressive, penetrates through cartilage rifts, and promotes osteolysis and loosening of implants. The observed sealing effect will act to prevent joint fluid to get access to the implant–tissue interfaces. Joint fluid is aggressive, can cause osteolysis, and can, clinically cause pain. These effects are liable to decrease with these findings and will further the longevity of these osteochondral implants.

Uric acid (UA) produced from purine metabolism is rather harmful to human health when its concentration is high. To better understand the application of hydroxyapatite (HAP) as an adsorbent for UA removal, quartz crystal microbalance (QCM) technique was employed to in situ investigate the adsorption behavior of UA on nanosized HAP coatings. This work was mainly focused on the mechanism and kinetics of UA adsorption. The obtained results showed that nanosized HAP coatings produced physical adsorption for UA, and the driving force of UA adsorption on HAP coatings was electrostatic interaction. The adsorption kinetic parameter estimated from the in situ frequency measurement was about 3.08 × 106 L/mol. The obtained information suggests that QCM measurement provides a useful method for monitoring the interaction between HAP and UA. Keywords: Uric acid, Nanosized hydroxyapatite coating, Mechanism, Kinetics, Quartz crystal microbalance

The optimization of the anodization process of Ti substrate for in situ synthesis of hydroxyapatite/titanium oxide composite coatings on titanium substrate was accomplished. The anodization was performed under 30, 60 and 90 V cell voltage, and the morphology of treated surface, as well as linear and surface roughness, were analysed by field emission-scanning electron microscopy, atomic force microscopy and roughness tester. It was shown by linear and surface roughness analyses that titanium anodized under 60 V has the highest roughness, whereas at 90 V the flattening of the surface occurs. As the highest surface roughness results emerged at 60 V, the novel process of composite anHAp/TiO2 coating synthesis, which comprises simultaneous processes of TiO2 formation and HAp deposition, as well as HAp impregnation within TiO2 surface layer, was performed at this voltage. Ti substrate surface was completely covered by composite coating, with no visible cracks. The adhesion quantified according to ASTM D3359-02 standard is considerably improved with respect to the coatings obtained by cathaphoretic processes, with no need of subsequent sintering. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON172060]

Chitosan is a cationic polymer that forms polymerized membranes upon reaction with anionic polymers. Chitosan−carboxymethyl cellulose (CMC) capsules are drug delivery carrier candidates whose mechanical strength and permeability must be controlled to achieve sustained release. In this study, the capsules were prepared from chitosan−γ-glycidoxypropyltrimethoxysilane (GPTMS)−CMC. The mechanical stability of the capsules was improved by crosslinking the chitosan with GPTMS. The capsules were then coated with hydroxyapatite (HAp) by alternately soaking them in calcium chloride solution and disodium hydrogen phosphate solution to prevent rapid initial drug release. Cytochrome C (CC), as a model drug, was introduced into the capsules via two routes, impregnation and injection, and then the CC released from the capsules was examined. HAp was found to be deposited on the internal and external surfaces of the capsules. The amount of CC introduced, and the release rate were reduced by the HAp coating. The injection method was found to result in the greatest CC loading.

This study aims at experimentally revealing the effects of damages/fractures in HAp coating layer of acetabular cups on loosening behavior of the acetabular cups. Aseptic loosening is occurred due to degradation of fixing force of acetabular cups by biological effects or mechanical loading. However, effects of mechanical loading on loosening behaviour have not been observed yet. In order to simulate cyclic loading conditions of gaits, a testing system which can load entire components of joint including acetabular cups and stem parts was designed. Moreover, by applying two positions of AE sensors during fatigue testing, it was possible to observe the damage behavior of HAp coating. AE measurement detected different failure modes of HAp coating, which were locally occurred at an edge part of the acetabular cup due to stress singularity at that region. In the cases of changing fixation angles, even though damages in simulated cancellous bone surrounding acetabular cups were less occurred, extents of rotational displacements were compatible with the one in an original fixation angle.

Biomaterials are natural or synthetic materials that are used in human body and are materials to evaluate, treat, support or replace any tissue, organ, or function of the body. Due to its favorable biocompatibility and mechanical properties, HA-coated metal-based implants are used in the orthopedic surgery operations. For this purpose, sol-gel synthesized nano sized HA powders were produced. Ti6Al4V alloy was coated with hydroxyapatite(HA) by using the sol–gel method. Surface morphologies, thermal, mineralogical properties and bioactivity of the coatings were examined and the characterization of the coatings was performed by using DTA-TG, XRD, SEM, and EDX.