Surface Modification of Titanium Implants for Improved Tendon Adhesion PDF Download

Author: Hannah Feinberg
Publisher:
ISBN:
Category : Biomedical materials
Languages : en
Pages : 156

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Author: Jenny E. Raynor
Publisher:
ISBN:
Category : Biomedical materials
Languages : en
Pages :

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Modification of the surface chemistry of materials used as implants in biomedical applications affords the ability to control cell adhesion, prevent inflammation and enhance integration with the host. Titanium and its alloys are strong and lightweight thereby making them desirable for applications such as hip and knee replacements, dental implants, and cardiac pacemaker implants. However, the lifetime of these implants is often limited by poor incorporation into the surrounding bone which results in loosening and wear. In order to overcome these limitations we have studied the modification of titanium substrates with a self-assembled monolayer that can be used to perform surface-initiated atom transfer radical polymerization (SI-ATRP) of a monomer to afford polymer brushes that effectively prevent the adhesion of cells. In addition, the polymer brushes afford the ability to tether a peptide sequence. Specific peptides containing adhesion sequences have been tethered to the polymer brushes. The resulting surfaces promote cell adhesion and osteoblast differentiation, thereby increasing bone tissue formation around the implant resulting in better incorporation of the implant.

Author: Yasmeen Janzeer
Publisher:
ISBN:
Category : Titanium
Languages : en
Pages : 412

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Author: Karan Gulati
Publisher:
ISBN: 9783031215667
Category :
Languages : en
Pages : 0

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This book provides a comprehensive technical and scientific overview of the surface modification of titanium dental implants. Coverage ranges from basic concepts of surface modification to advanced micro- and nano-engineering strategies employed to achieve augmented bioactivity to meet the needs of compromised patient conditions. A special focus of the book is advanced state-of-the-art electrochemically anodized nanostructures fabricated on implants towards enhanced bioactivity and local therapy. Surface Modification of Titanium Dental Implants will keep you current in the domain of titanium dental implants and will provide an improved understanding of their performance and application. The book will benefit engineers, clinicians, and researchers in biomaterials, biomedical engineering, dental and bone implants, nano-engineering, and technology. Provides a detailed look at surface modification of titanium-based dental implants from micro to nanoscale; Focusses on nano-engineered titanium to achieve desirable implant functions; Highlights key developments and identifies clinical translation challenges.

Author: Charlotte Campana
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Titanium implants are nowadays often used in orthopedics and dentistry to repair or replace bone injuries or defects caused by aging, accident or diseases. Even if titanium is biocompatible, a low osseointegration between the implant and the surrounding tissue may result in graft rejection and a series of unwanted reactions. To overcome these issues, two main strategies have been investigated: a physicochemical modification of the implant surface (e.g. roughness, energy or chemistry of the surface) or a functionalization of the surface with cell adhesive molecules. This research project will mainly focus on the second approach which consists on the biofunctionalization of the surface. There are many types of cell adhesive molecules that can be used for such purpose. One of the most common family of cell adhesive molecules used are the proteins found in the extra cellular matrix (ECM).The cell bonding activity of these proteins is usually contained within a few amino acids. This is the case of the sequence Arg-Gly-Asp (RGD) found in many proteins of the ECM. Thus, the use of these short peptide sequences has been explored to biofunctionalize materials and to improve cell adhesion. To create a covalent and stable binding between the peptides (organic molecules) and the titanium surface (inorganic surface), the use of linker molecules is required. This can be achieved by using organosilanes. The aim of this project is to improve the adhesion of the osteoblasts onto the titanium graft. In order to do so, different activation methods of the titanium surface will be explored followed by a silanization step that ensure the attachment of the peptides to the surface. Then, RGD peptides will be immobilized to improve the binding of the cells on the surface. The central theme of this research will be to compare two methods that increase and accelerate the adhesion of the cells in order to decrease the risk of complications. The first method is a simple physisorption of the peptide onto the implant surface and the second method is a creation of a strong covalent bond between the surface of the implant (made of titanium) and the peptides. The effect of the distinct activation treatments on the physicochemical properties of the surfaces will be investigated by means of contact angle measurements, interferometry, scanning electron microscopy and X-ray photoelectron spectroscopy. The biological properties of the functionalized materials will be explored by means of cell adhesion assays with osteosarcoma cells.

Author: Kyo-Han Kim
Publisher:
ISBN: 9781608765393
Category : Coatings
Languages : en
Pages : 0

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This book starts with concepts of bone, its structure, remodelling, materials for implants and implant testing methods. Calcium phosphate ceramics and need for titanium surface modification are detailed in the initial chapters. Surface modification techniques include plasma spraying, sol-gel, biomimetic, electrochemical, laser, sputtering and ion-implantation methods. Chapters 5 to 19 deal with these modification techniques. Chapters 20-22 deal with less-common methods titanium nitride coating, protein modification, diamond like carbon coating and ultraviolet treatment. Substituting the apatite lattice with other cations like silicon, magnesium, sodium, carbon, etc is provided. The chapters involving these techniques begin with a small introduction about that technique and go on to explain the underlying principles, methodology and properties of the coats. According to the authors, the book gives a complete overview of almost all the surface modification techniques known, as applied to titanium biomaterials.

Author: Ranj Salaie
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Ellen Elizabeth Sauter
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ISBN:
Category : Artificial joints
Languages : en
Pages : 140

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Currently, the lifetime of a typical orthopaedic implant is only 15-20 years, a lifetime that many patients are outliving. Therefore, implants with superior longevity need to be engineered. To improve implant longevity, much research has been focused on creating micro-scale porosity/roughness to enhance osseointegration by mechanical interlocking of bone and implant. These structures have improved osseointegration to the current 15-20 year lifespan. It has also been shown that nano-scale structures enhance osteoblast (bone cell) function. The combination of micro-scale and nano-scale structures into one hierarchical structure may further improve the osseointegrative properties of implants. A hierarchical surface modification consisting of titanium dioxide [(TiO2)] nanotubes produced by anodic oxidation of titanium in an electrolyte containing fluoride ions, [F], on a commercially pure (cp) titanium, micro-scale grid structure produced by laser powder deposition was successfully developed. [TiO2] nanotubes were characterized using field emission scanning electron microscopy (FE-SEM), while laser deposited grid structures were characterized with both FE-SEM and optical microscopy. Mouse preosteoblasts were used to evaluate the in vitro biological effects, including cell morphology and cell viability, on the four experimental groups: unanodized flat, anodized flat, unanodized laser deposition, and anodized laser deposition. All treatment groups showed good cell attachment and spreading; however, it was observed that on the samples with [TiO2] nanotubes there was a much greater density of adhesion proteins. The presence of these proteins provides a surface that cells can more readily attach to which can lead to greater cell proliferation and differentiation. Also, viability of cells on samples with nanotubes was higher than samples without nanotubes. However, viability was highest on the anodized flat surface, suggesting that the micro-scale grid on the surface of laser deposition samples did not positively affect the osteoblasts. Optimization of the micro-scale surface features, along with anodization of the micro-scale structures, could possibly further improve the bone/implant interaction and further study is needed on this topic.

Author: Alexander Medvedev
Publisher:
ISBN:
Category :
Languages : en
Pages : 360

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Titanium and its alloys have long been in the focus of biomedical research as some of the most suitable materials for implant production. This fact is attributed to an excellent combination of mechanical, biological and physico-chemical properties, such as low density and high mechanical strength, resulting in the highest specific strength among most common implant materials, reduced elastic modulus (compared to stainless steel or CoCrMo alloys), excellent corrosion resistance, and enhanced biocompatibility.Recently, titanium alloy Ti6Al4V, the most common titanium implant material so far, was in the focus of several studies that claimed it has a potential to be toxic to humans due to the release of aluminium and vanadium ions in the surrounding tissues when placed within the host. This problem can be overcome by using titanium with lower alloying content, for example, commercially pure (CP) titanium, such as Grade 2 or Grade 4. Unfortunately, CP titanium shows significant decrease in mechanical properties compared to Ti6Al4V. There are ways, however, to enhance the strength of materials without altering their chemical composition. Particularly, severe plastic deformation (SPD) has been shown to dramatically enhance the strength of various materials while retaining good ductility.It is well known that the surface of medical implants plays a crucial role in the success and outcome of the surgery and determines the longevity of implants. Therefore, it is common to modify the surface of these devices in order to increase the surface area, alter its chemistry or wettability. There are numerous techniques available nowadays that allow modification of implant surface, however, only a handful of them were implemented in industry. One of such processes - SLA (Shot-blasted with Large grit and Acid etching) - is considered one of the most promising since it has been adopted by several different companies around the world. The main aim of the present work was to use SPD to increase the strength of CP titanium of two purity grades - Grade 2 and Grade 4 - in order to develop a material that, as a result of a combination of high strength and good biocompatibility, could be used to replace Ti6Al4V as a major titanium-based material on the market. Moreover, we performed all experiments on samples with two distinctly different types of surfaces - polished and SLA-treated - to highlight the effect of grain refinement on the outcome of subsequent surface modification. To the best of our knowledge, no work examining a combined effect of grain refinement and surface modification on mechanical and biological properties has been previously described in the literature. The results discussed in this thesis suggest that, as a result of a significant refinement of microstructure by SPD processing, mechanical properties of CP titanium can match (fatigue) or even exceed (tensile) those of Ti6Al4V. It was observed that SLA treatment results in the formation of a surface layer with refined structure which aided in enhancing fatigue properties of as-received titanium after surface modification. Although such layer was not found in case of SPD-processed samples, which led to a slight decrease of fatigue life compared to samples with polished surface, fatigue properties of SPD-processed titanium were still superior to those of Ti6Al4V. Fatigue testing in simulated body fluid, designed to test how titanium with refined structure reacts to aggressive environment, indicated no deterioration of fatigue life of titanium, regardless of microstructure.It has been demonstrated that surface properties of titanium were notably influenced by the grain size and the subsequent SLA treatment. Roughness of polished samples was shown to be a function of the grain size of material. At the same time, mechanical properties are believed to be responsible for differences in roughness of SLA-modified surface, as surface roughening primarily occurs by means of grit-blasting with its effect highly dependent on the strength/ductility of the surface. Wettability of titanium has been observed to be determined by the surface texture, being a product of variations in the processing route. This effect retained after severe surface roughening as well, although, overall, surface of SLA-treated titanium samples were found to be much more hydrophobic. Simultaneously, variations in wettability between samples of different conditions became less pronounced. Chemical analysis of CP Ti with varying microstructure and surface quality revealed no effect of microstructure on the chemical state of the polished surface. At the same time, it was noted that SLA treatment of ultrafine-grained titanium may favour the formation of a thicker, more chemically uniform oxide layer. Finally, an assessment of biological properties of CP Ti has been made. The results indicate a positive effect of ultrafine-grained structure and associated surface properties on the attachment, proliferation and differentiation of two types of tissue cells - human osteosarcoma SaOS-2 cells and adipose-derived mesenchymal stem cells (adMSC) on both types of surfaces. At the same time, bacterial adhesion was also significantly enhanced on the surface of SLA-treated titanium. This fact suggests that an utilisation of surface modification techniques in industrial processes of implant production should be most carefully controlled in order to reduce possibility of serious complication that may be caused by bacterial colonisation.Overall, experimental results presented in this thesis indicate that SPD, especially in combination with surface modification techniques, such as SLA treatment, has a great potential to improve both mechanical and biological properties of commercially pure titanium to make it a highly favourable and competitive candidate for the replacement of Ti6Al4V alloy. Our research suggests that there may be only one potential drawback of a combination of SPD and SLA, namely, enhanced adhesion of bacterial cells on the surface of such materials. However, this negative effect is not attributed to SPD processing, but rather to the increased surface roughness inherent to the SLA treatment. We suggest that this issue can be addressed by developing proper handling, storage and pre-implantation preparation protocols, a process that was not covered in current work but could be included as a part of the basis for the future work.

Author: Kennedy Omoniala
Publisher:
ISBN:
Category :
Languages : en
Pages :

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