Download or read book Development of Radio opaque Bioglass Hydroxyapatite coatings deposited by HVOF and SPS thermal spray for biomedical applications written by Germán Andrés Clavijo Mejía and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'hydroxyapatite (HAp) et le verre bioactif (BG) 45S5 sont largement utilisés comme précurseurs des revêtements fabriqués par projection thermique pour améliorer la biocompatibilité des implants biomédicaux. Ceci, en raison de la structure similaire de l'HAp avec le tissu osseux et la haute réactivité de ce BG en milieu biologique, ce qui permet la croissance rapide du tissu osseux à sa surface. La projection combinée des deux matériaux permet d'obtenirdes revêtements hautement bioactifs et stables par rapport aux revêtements individuels. De plus, la bioactivité de l'HAp et la radio-opacité de BG45S5 peuvent être améliorées en utilisant comme matières premières des sources naturelles, telles que l'HAp issue d'os de bovins (BHAp) et en ajoutant des radiopacifiants tels que l'oxyde de bismuth (Bi2O3) à la structure du BG. Par conséquent, des revêtements combinés avec une bioactivité et une opacité accrues vis-à-vis des rayons X peuvent être obtenus pour améliorer le diagnostic non invasif par radiographie des implants biomédicaux revêtus.Cette recherche présente le développement de couches épaisses biocompatibles et opacifiées réalisées par projection thermique, flamme haute vitesse (High-Velocity Oxygen Fuel, HVOF) et plasma (Atmospheric Plasma Spray, APS). La composition chimique, la structure, la microstructure et la bioactivité des couches radio-opaques de BHAp/BG45S5+Bi2O3 obtenues sont étudiées ainsi que les propriétés des matériaux de départ. ainsi que la projection gradient du revêtement combiné. En particulier, la bioactivité de différentes architectures de revêtements (monocouches, couches à gradient de matériaux et multicouches) a été évaluée. Les résultats expérimentaux montrent que la poudre de départ de BHAp est principalement constituée d'apatite carbonée de type B avec une pureté élevée de la phase HAp. Les poudres de bioverre BG45S5 fabriquées en laboratoire présentent une composition chimique et des propriétés physiques très similaires à celles du BG45S5 commercial.Un pourcentage en poids de 1 à 20 % d'oxyde de bismuth Bi2O3 a été ajouté au verre bioactif pour modifier sa radio-opacité. Les images radiographiques des composés BG45S5 + x% Bi2O3 montrent que le bioverre avec 10% en poids d'oxyde de bismuth permet d'augmenter de 3,6 fois l'opacité du bioverre de manière homogène sans affecter de manière notable ses propriétés structurales et thermiques. En ce qui concerne les revêtements réalisés par projection thermique, la teneur en CO32- et en Mg dans la poudre de BHAp conduit à la formation de dolomite dans la phase cristalline de la surface du revêtement monocouche de BHAp réalisé par HVOF alors que celui réalisé par APS ne montre aucune phase secondaire cristalline à sa surface. Une couche d'apatite typique est mise en évidence à la surface des deux revêtements après 3 jours d'immersion dans un fluide corporel simulé (SBF), cependantle revêtement monocouche de BHAp réalisé par HVOF montre une délamination après 5 jours d'immersion. Par conséquent, la projection plasma APS a été choisie pour élaborer les revêtements monocouches de BHAp, BG45S5, BG45S5+10wt.% Bi2O3 et le revêtement à gradient de composition de BHAp/BG45S5+10wt. % Bi2O3. Le revêtement monocouche de BG45S5 + 10wt.% Bi2O3 a une microstructure et une structure amorphe similaires à celles du revêtement monocouche de BG45S5 sans Bi2O3 réalisé par projection plasma de la poudre commerciale . Cependant, une délamination et une vitesse réduite de formation de la couche d'apatite ont été observées. Le revêtement à gradient de composition de BHAp/BG45S5+10 wt. % Bi2O3 montre un taux de croissance de la couche d'apatite similaire à celui du revêtement monocouche de BG45S5+10wt. % Bi2O3. La formation d'apatite observée après 10 jours d'immersion dans un fluide corporel simulé ne présente pas de délaminage à la surface du revêtement grâce au gradient de composition du BG45S5 10 wt. % Bi2O3 combiné au BHAp.

Download or read book Microplasma Sprayed Hydroxyapatite Coatings written by Arjun Dey and published by CRC Press. This book was released on 2015-03-19 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been enormous growth in the use of medical implants. However, in the case of hip replacement, loosening of metallic prosthesis fixed with polymethylmethylacrylate bone cement has resulted in painstaking revision surgery, which is a major problem for the patient, surgeon, and biomedical technology itself. In fact, global recognition of thi

Download or read book Hydroxyapatite Coatings for Biomedical Applications written by Sam Zhang and published by CRC Press. This book was released on 2013-05-14 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydroxyapatite coatings are of great importance in the biological and biomedical coatings fields, especially in the current era of nanotechnology and bioapplications. With a bonelike structure that promotes osseointegration, hydroxyapatite coating can be applied to otherwise bioinactive implants to make their surface bioactive, thus achieving faster healing and recovery. In addition to applications in orthopedic and dental implants, this coating can also be used in drug delivery. Hydroxyapatite Coatings for Biomedical Applications explores developments in the processing and property characterization and applications of hydroxyapatite to provide timely information for active researchers and newcomers alike. In eight carefully reviewed chapters, hydroxyapatite experts from the United States, Japan, Singapore, and China present the latest on topics ranging from deposition processes to biomedical applications in implants and drug delivery. This book discusses: Magnetron sputtering and electrochemical deposition The modification of hydroxyapatite properties by sol–gel deposition to incorporate other elements found in natural bones, such as zinc, magnesium, and fluorine The use of pure hydroxyapatite in drug delivery applications The growth or self-assembly of hydroxyapatite on shape memory alloy Hydroxyapatite composite coatings—with carbon nanotubes, titanium dioxide (TiO2), and others—on the titanium alloy Offering valuable insights and a wealth of data, including numerous tables and figures, this is a rich source of information for research on hydroxyapatite coatings. Each chapter also covers material that provides an accessible stepping stone for those who are new to the field.

Download or read book Hydroxyapatite written by Yoshiki Oshida and published by Momentum Press. This book was released on 2014-12-01 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evidence-based literature reviews can provide foundation skills in research-oriented bibliographic inquiry, with an emphasis on such review and synthesis of applicable literature. Information is gathered by surveying a broad array of multidisciplinary research publications written by scholars and researchers. This book is based on a review of about 2,000 carefully selected articles about hydroxyapatite (HA) materials from about 150 peer-review journals in both engineering and medical areas and presents itself as a typical example of evidence-based learning (EBL). HA is very unique material which has been employed equally in both engineering and medical and dental fields. In addition, the name “apatite” comes from the Greek word απατw, which means to deceive. What is actually happening inside the apatite crystal structure is based on the unique characteristics of ion exchangeability. Because of this, versatility of HA has been recognized in wide ranges, including bone-grafting substitutes, various ways to fabricate HAs, HA-based coating materials, HA-based biocomposites, scaffold materials, and drug-delivery systems. This book covers all these interesting areas involved in HA materials science and technology.

Download or read book Coatings of Bioactive Glasses and Hydroxyapatite and Their Properties written by Andrea Cattini and published by . This book was released on 2013 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last decades, biomedical research has acquired a growing importance. Moreover, the progressive population ageing, with related musculoskeletal disorders, is driving the development of innovative materials for bone implants. Though the production of prosthetic implants is nowadays a mature and well-established practice, the scientific research is constantly evolving with the aim of improving the reliability and effectiveness of the available prostheses, thus increasing their life expectancy. The purpose of the present study is the production of new-generation coatings to support the adhesion between prosthetic implants and bone tissues. Bioactive materials, which are ones that elicit a specific biological response at their interface, were selected as coating materials. The new coatings were produced with hydroxyapatite and/or bioactive glass, two bioactive materials which are able to bond to bone. In particular, hydroxyapatite is a ceramic material whose composition and structure are very similar to those of the mineral component of bones. Moreover hydroxyapatite is highly stable in biological environment. For these reasons, this ceramic is currently the most widely used bioactive material to produce coatings for orthopaedic implants. Bioactive glasses, instead, are special glasses which exhibit a great bioactivity. Unfortunately, the use of hydroxyapatite and bioactive glasses in structural applications is limited by their mechanical properties, in particular their brittleness. To solve this problem, hydroxyapatite and bioactive glasses can be successfully used as coatings on metal prostheses. In this way the bone-bonding ability of bioactive materials is combined with the high mechanical properties of metals. Plasma spray is an established technique to produce bioactive coatings. In this study, a recent evolution of this process has been used i.e. the suspension plasma spray. The main difference between the new technique and the conventional one resides in the feedstock materials. In fact, the new process uses suspensions instead of dry powders which makes it possible to process sub-micrometric or nanometric particles and therefore to obtain coatings with an extremely fine and controlled microstructure. In the first part of this work, bulk bioactive glasses with different compositions were studied in order to select the most promising one for the coatings production. Specifically, a study to compare their in vitro bioactivity was carried out. Following, the deposition parameters to produce bioactive glass coatings were optimized. The coatings were characterized from a microstructural and mechanical point of view; also preliminary in vitro tests were carried out to assess the reactivity in physiological media. Then, a bioactive glass topcoat was applied on traditional hydroxyapatite coatings to increase their bioactivity. Since the topcoat showed the ability to promote coatings in vitro reactivity, the study progressed with the realization of specific composite systems using the hydroxyapatite and bioactive glasses. Accordingly, composite bioactive glass/hydroxyapatite coatings were produced and analysed. Three different microstructures were produced: conventional composite coatings (the constituent phases were evenly and randomly distributed); bi-layer coatings (the coatings included a hydroxyapatite bond coat and a bioactive glass topcoat); functionally graded coatings (the composition gradually changed from pure hydroxyapatite, in contact with the metal substrate, to pure bioactive glass, on the working surface). The basic goal was to merge the high bioactivity of bioactive glasses with the stability of hydroxyapatite. On account of the results of an introductory characterization, the graded structure was selected for further optimizations. New graded coatings were produced and analysed; in particular, their microstructure and mechanical properties were investigated before and after in vitro tests. In this way, both the bioactivity and the stability of the coatings could be estimated.

Download or read book Bioceramic Coatings for Medical Implants written by Robert B. Heimann and published by John Wiley & Sons. This book was released on 2015-03-10 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the progress in recent years, this book provides in-depth information on the preparation, chemistry, and engineering of bioceramic coatings for medical implants. It is authored by two renowned experts with over 30 years of experience in industry and academia, who know the potentials and pitfalls of the techniques concerned. Following an introduction to the principles of biocompatibility, they present the structures and properties of various bioceramics from alumina to zirconia. The main part of the work focuses on coating technologies, such as chemical vapor deposition, sol-gel deposition and thermal spraying. There then follows a discussion of the major interactions of bioceramics with bone or tissue cells, complemented by an overview of the in-vitro testing methods of the biomineralization properties of bioceramics. The text is rounded off by chapters on the functionalization of bioceramic coatings and a look at future trends. As a result, the authors bring together all aspects of the latest techniques for designing, depositing, testing, and implementing improved and novel bioceramic coating compositions, providing a full yet concise overview for beginners and professionals.

Download or read book Bioactive Antibacterial Composite Coatings Deposited By Cold Spray written by Kiran Judd and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Tissue damage, loosening of implants, and the infection of the body are some of the most common complications that arise following surgical procedures. In dental and orthopedic medical implants infections are largely caused by the adhesion and growth of bacteria on the implant surface. Additionally, anatomical differences between the surrounding tissue/bone and the implant material can cause further complications. The usage of biomaterial-based implant coatings has been fundamental to the application of medical implants/devices and have improved mechanical properties. Successful implants must have favorable mechanical properties/wear resistance, provide strong biocompatibility/bioactivity, and display antibacterial properties. To date, bioactive coatings have generally been deposited using thermal spray methods such as plasma spray; however, this method of deposition has led to the melting and degradation of novel bioactive properties of hydroxyapatite (HA) as well as poor coating adhesion. This study discusses a novel approach of depositing biocompatible, bioactive, and antibacterial coatings well below their melting point using the cold spray process. The cold spray process was used to deposit composite powders with 70 wt% titanium (Ti), 20 wt% hydroxyapatite (HA), and 10 wt% chitosan (CS) onto aluminum 6061 (Al6061) substrates. The effect of process parameters was examined and the goal was to achieve antibacterial well-bonded coatings. The biofunctionality and corrosion resistance was investigated by a bacterial cellular assay and corrosion testing in the simulated body fluid (SBF) Hank's Balanced Salt Solution (HBSS). These tests compared the bacterial and corrosion resistance of composite coatings with commonly used implant substrate materials. The preliminary results indicate the phase composition of the Ti and HA remained the same before and after coating deposition. However, it is inconclusive whether CS particles remained in the same phase following deposition. Porous Ti/HA/CS coatings were obtained with more than double the porosity of Ti/HA coatings. Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings was carried out using Field Emission Scanning Electron Microscope/Energy-Dispersive X-ray Spectroscopy (FESEM/EDS) and X-ray Powder Diffraction (XRD). The addition of the CS in the coating offered no improved antibacterial properties when compared to plain Al6061, 316 stainless steel (SS316), and titanium-6 aluminum-4 vanadium (Ti-6Al-4V) substrate samples. The reason for this lack of protection is still being investigated and could be attributed to a change in phase during the application or an insignificant amount of CS depositing.

Download or read book Hydroxyapatite based Architectured and Nano structured Bioactive Coatings Fabricated by Cold Spray written by Alberto Ion and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cold spray (CS) is considered as a solid-state coating process by impact. As a result, the harmful effects of high-temperature oxidation, evaporation, melting, crystallization, residual thermal stresses, etc., encountered with traditional thermal spray techniques, are minimized or even eliminated. CS can be of interest in the field of biomedical coatings for Bone Tissue Engineering (BTE), namely hydroxyapatite (HAp) coatings. CS can avoid HAps phase transformation into other calcium phosphates (tricalcium phosphate, tetracalcium phosphate, calcium oxide) during the deposition. Our work here first focuses on CS of HAp-based materials while analyzing in details all the CS processing steps (formation of “splats”, adhesion process and further growth process). More specifically, the influence of the raw powder mechanical properties, substrate surface state (i.e. roughness,hardness), CS pressure and stand-off distance between the gun and the substrate, are investigated. Good quality coatings can be obtained while optimizing the aforementioned parameters. It is shown that the build-up of coatings is mostly due to physical phenomena linked to particles packing ability and mechanical anchor on the roughness of the substrate. No consolidation through chemical phenomena is activated leading to coatings with a poor adhesion. Taking advantage of CS, in a second step we extend the approach to novel functionaly-graded enhanced bio-active hybrid coatings introducing whether collagen, bioglass or antimicrobial silver nanoparticles in the HAp feestocks. The as-obtained coatings are then tested at the microstructural, mechanical and biological (in vitro) levels showing good biocompatibility for BTE.

Download or read book Hydroxyapatite and Other Calcium Orthophosphates written by Sergey V. Dorozhkin and published by Nova Science Publishers. This book was released on 2017 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the inorganic constituents of skeletons, dentine and the enamel of teeth in all vertebrates, as well as antlers of male deer, calcium orthophosphates (CaPO4) appear to be the key materials to sustain all life on Earth. Therefore, biologically relevant CaPO4 possess all the necessary features of the biomaterials, such as biocompatibility, bioactivity, bioresorbability, osteoconductivity, osteoinductivity, and appear to be non-toxic, non-inflammatory and non-immunogenic. In this book, the author presents current state-of-the-art applications of CaPO4 as bioceramics, deposits (coatings, films and layers) and in dentistry. Topics discussed include chemical composition and preparation, forming and shaping, sintering and firing for CaPO4-based bioceramics, chemical composition and preparation, pre- and post-deposition treatments for CaPO4-based deposits, followed by the detailed description of their major properties, biomedical applications and in vivo behavior. The detailed description of current CaPO4 applications in dentistry both for dental caries prevention and as various types of dental treatments is given in the last section of this book.

Download or read book Medical Coatings and Deposition Technologies written by David Glocker and published by John Wiley & Sons. This book was released on 2016-07-11 with total page 637 pages. Available in PDF, EPUB and Kindle. Book excerpt: Medical Coatings and Deposition Technologies is an important new addition to the libraries of medical device designers and manufacturers. Coatings enable the properties of the surface of a device to be controlled independently from the underlying bulk properties; they are often critical to the performance of the device and their use is rapidly growing. This book provides an introduction to many of the most important types of coatings used on modern medical devices as well as descriptions of the techniques by which they are applied and methods for testing their efficacy. Developers of new medical devices and those responsible for producing them will find it an important reference when deciding if a particular functionality can be provided by a coating and what limitations may apply in a given application. Written as a practical guide and containing many specific coating examples and a large number of references for further reading, the book will also be useful to students in materials science & engineering with an interest in medical devices. Chapters on antimicrobial coatings as well as coatings for biocompatibility, drug delivery, radiopacity and hardness are supported by chapters describing key liquid coating processes, plasma-based processes and chemical vapor deposition. Many types of coatings can be applied by more than one technique and the reader will learn the tradeoffs given the relevant design, manufacturing and economic constraints. The chapter on regulatory considerations provides important perspectives regarding the marketing of these coatings and medical devices.

Download or read book Modified Inorganic Surfaces as a Model for Hydroxyapatite Growth written by Lilyana Pramatarova and published by Trans Tech Publications Ltd. This book was released on 2006-03-03 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The process by which organisms in Nature create minerals is known as biomineralization - a process that involves complex interactions between inorganic ions, crystals and organic molecules; resulting in a controlled nucleation and growth of minerals from aqueous solutions. During the last few decades, biomineralization has been intensively studied, due to its involvement in a wide range of biological events; starting with the formation of bones, teeth, cartilage, shells, coral (so-called physiological mineralization) and encompassing pathological mineralization, i.e. the formation of kidney stones, dental calculi, osteoporosis, arteriosclerosis, osteogenesis imperfecta, etc. During the same period, biomineralization has become a hot topic for world-wide research throughout the world, due to the growing expectations of a good quality and duration of life by the ever-increasing population of the aged. Young people, in particular, also make increasing demands on the quality and the appearance of the existing implants available on the market. The general goals of research and manufacture are now to create and improve implants for various applications in the human body, as well as to prevent diseases leading to the formation of minerals such as hydroxyapatite (implicated, for example, in osteogenesis, kidney stones, dental calculi, arteriosclerosis – all problems which mainly affect women). The results presented in this book will make a significant contribution to the application of the modified surfaces of widely-studied materials as a model system for hydroxyapatite-coating, to the cultivation of cells on surfaces, as well as to the growth of hydroxyapatite by applying new technologies (such as laser-liquid-solid interaction) that facilitate nucleation and growth. In this way, materials and layers having possible applications as implants, biosensors, etc. can be obtained. The in vitro system described here is universal and can be applied not only to the production of hydroxyapatite coatings for implants, but also to investigating the basic mechanisms of mineral-formation diseases and thus identify new directions for prophylaxis. This will then make a strong contribution to improving the quality and duration of life of the population.

Download or read book Functionalized Coatings by Cold Spray for Joint Prosthesis written by Anna Martín Vilardell and published by . This book was released on 2017 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cold Spray (CS) is a novelty technique for the production of coatings within the field of Thermal Spray. The use of low work temperatures (under the melting point of the material) is what makes it different from the other conventional spraying techniques. CS is an ideal technique to spray materials that are sensitive to temperature, such as nanostructured and amorphous materials, or sensitive to the oxygen, as could be titanium. These characteristics may be specially promising within the field of biomedical coatings. Compared to the conventional processes, it would allow to produce coatings in a more cost-effect and environmental friendly way. The research is mostly focused on the obtaining of highly rough Commercial Pure Titanium (CP-Ti) and Calcium Phosphate (CP) coatings by CS for joint prosthesis application. An exhaustive development of coating parameter optimization has been developed and the different deposition mechanisms for each feedstock powder were analyzed as well. The mechanical and biological properties of the optimal coatings were evaluated consequently. The mechanical testing (e.g. Tensile and shear strength test and Taber test), was performed on the optimized CP-Ti coating overcoming the ASTM standard specifications for joint, shoulder and knee prosthesis; CP-Ti coating showed good bonding between particles as well with the substrate. The used of coarse titanium particles provided high roughness (Ra=40±12 æm and Rz=235±44 æm) that shows an increase in cell viability, proliferation and differentiation as well as mineralization, in comparison with a low-roughness titanium surface obtained by Sand Blasted (SB). Afterwards, additional surface modification procedures were investigated to obtain nanotextured surfaces on the as-sprayed CS titanium coatings to evaluate their in-vitro response for comparison. The anodic oxidation treatment leads to a TiO2 Nanotube (NT) layer with a pore diameter between 50-100 nm and a roughness of Ra=36.8±4.6 nm, whereas the alkaline treatment leads to a nanosurface of Ra=1.2±0.2nm, composed by very fine porosity 100nm. The nanotextured treatments lead to an increase of cell viability in comparison with the as-sprayed CP-Ti coating as well as high cell differentiation due to its nanofeatures. On the other hand, Hydroxyapatite (HA) coatings were well-deposited by CS without amorphization. Two different HA powders were used as feedstock, a sintered HA powder with a crystalline microstructure, and agglomerate HA feedstock powder with a nanocrystalline microstructure. Both powders show different deposition by CS according to their microstructure; particle deposition of sintered HA powder occurred by slight void collapse and dynamic fragmentation followed by cracking and crushing and reduction in crystal size by plastic deformation mechanisms, whereas agglomerate HA powder a consolidation between particles is caused by the tamping effect produced by the continuous impact of incoming particles onto the already adhered ones, leading to coating build up. Although sintered HA coatings show high cell differentiation, agglomerated HA coatings result in higher cell viability and proliferation, as well as a more homogeneous cell deposition along the coating; agglomerate HA coatings were compared to HA coatings obtained by conventional techniques (e.g. Plasma Spray), and an increase of cell viability and proliferation were observed according to the crystalline HA percentage (CSPS). To sum up, CS has shown to be suitable to produce metallic and ceramic coatings for joint applications, especially those dealing with materials that are sensitive to the temperature and oxygen. The non-microstructural changes from the feedstock powder to the coatings leads to a big advantage in CS to obtain customized coatings.

Download or read book Synthesis of Hydroxyapatite Coatings for Biomedical and Catalytic Applications written by Xuefei Zhang and published by . This book was released on 2018 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Hydroxyapatite (Ca10(PO4)6(OH)2, HA) has drawn considerable interest in biomedical and catalytic applications due to its excellent biocompatibility, adsorption capacity, and ion exchange capacity. The first part of this thesis focused on imparting antibacterial property to HA coatings for biomedical applications. Ag nanoparticles were electrochemically deposited on HA coatings. The Ag/HA composite coatings displayed inconsistent antibacterial properties. Heat treatment was found to improve the antimicrobial activity of the composite coatings because the oxidation of Ag nanoparticles was enhanced by the heat treatment and thus more Ag+ ions can be released to inhibit the bacterial growth. Antibacterial coatings were also obtained by electrochemically depositing HA coatings on TiO2 nanotubes prepared by anodization of Ti plates. A model drug compound was loaded in the HA/nanotubular TiO2 composite coatings. The drug release profile of the coating exhibited an initial burst release followed by a sustained release. Tests of bacterial growth and deposition of calcium phosphate from simulated body fluid suggest that the antibioticsloaded HA/nanotubular TiO2 composite coatings can inhibit the growth of bacteria without compromising bioactivity."--Pages xi-xii.

Download or read book Science and Medical Applications of Hydroxyapatite written by Hideki Aoki and published by Medico Dental Media International. This book was released on 1991 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydroxylapatite Coatings in Orthopaedic Surgery written by Rudolph G. T. Geesink and published by Raven Press (ID). This book was released on 1993 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book In vitro Investigation of Air plasma Sprayed Hydroxyapatite Coatings Deposited on Two Geometrically Different Substrates written by Tshepo Paul Ntsoane and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, coatings of hydroxyapatite (HAp) prepared by thermal spraying technique are investigated for biological response. Spraying was done on two geometrically different Ti-6Al-4V alloy substrates under atmospheric conditions. Subsequent immersion experiments, mimicking physiological environment, were carried out using simulated body fluids (SBF). Non-destructive techniques utilizing conventional and high-energy synchrotron diffractometry were employed for depthaÌ22́Ơ0́−resolved investigations of phase composition, crystallinity and residual stresses within the coating for both substrate geometries. Microscopy techniques were used to examine surface morphology and microstructure. In both substrate geometries and for all immersion periods, HAp is the predominant phase with tetra-calcium phosphate (TTCP) and tri-calcium phosphate (TCP) the two main thermal products. The coating deposited on cylindrical rod substrate show a higher volume fraction of HAp at the near-surface region for the as-sprayed condition and samples immersed for 7 and 28 days. Further immersion shows the former decreasing gradually while the latter saturates after 28 days. Thermal products TTCP and TCP, for the coating deposited on the flat geometry substrate decreased with immersion, while those deposited on the cylindrical rod remains roughly the same before increasing slightly. Through-thickness behavior shows the as-sprayed HAp increasing almost linearly with depth, reaching a maximum around the coating midpoint before decreasing with further depth. Immersion in SBF does not alter the general trend across the coating however it increased the volume fraction of HAp within the first half of the coating with the biggest change occurring between 7 and 28-days of immersion. The variation of HAp with depth and immersion at the three lateral positions shows agreement within error bars indicating the coating to be homogenous. The trend is observed for coating deposited on cylindrical substrate geometry. Both substrate geometries show high near-surface region crystallinity with an index of ~90%. The interface region is less crystalline with a degree of crystallinity index of 67% and 56% for the flat and cylindrical substrates, respectively. Immersion in SBF does not alter the general through-thickness trend however it increased the degree of crystallinity at both ends. Residual stresses for the coating deposited on both substrate geometries are tensile and small, not exceeding 42 MPa and 65 MPa, respectively. The stresses are mainly confined in the near-surface region with the interior region showing neglible stresses,

Download or read book Physical Vapor Deposited Biomedical Coatings written by George E Stan and published by Mdpi AG. This book was released on 2021-11-22 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book outlines a series of developments made in the manufacturing of bio-functional layers via Physical Vapour-Deposited (PVD) technologies for application in various areas of healthcare. The scrutinized PVD methods include Radio-Frequency Magnetron Sputtering (RF-MS), Cathodic Arc Evaporation, Pulsed Electron Deposition and its variants, Pulsed Laser Deposition, and Matrix-Assisted Pulsed Laser Evaporation (MAPLE) due to their great promise, especially in dentistry and orthopaedics. These methods have yet to gain traction for industrialization and large-scale application in biomedicine. A new generation of implant coatings can be made available by the (1) incorporation of organic moieties (e.g., proteins, peptides, enzymes) into thin films using innovative methods such as combinatorial MAPLE, (2) direct coupling of therapeutic agents with bioactive glasses or ceramics within substituted or composite layers via RF-MS, or (3) innovation in high-energy deposition methods, such as arc evaporation or pulsed electron beam methods.