Author: Michael J. Avaltroni
Publisher:
ISBN:
Category :
Languages : en
Pages : 268

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Book Description

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

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Book Description
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: Yoshiki Oshida
Publisher: Elsevier
ISBN: 0080467199
Category : Technology & Engineering
Languages : en
Pages : 447

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Book Description
This unique book about bioscience and the bioengineering of titanium materials is based on more than 1,000 published articles. It bridges the gap between the medical/dental fields and the engineering/technology areas, due to the author’s unique experience in both during the last 30 years. The book covers Materials Classifications, Chemical and Electrochemical Reactions, Oxidation, Biological Reactions, Implant-related Biological Reactions, Applications, Fabri-cation Technologies, Surface Modifications, and Future Perspectives. * Provides quick access to the primary literature in this field* Reviews studies of titanium materials in medical and dental applications, as reported in nearly 1,500 articles published over last several years* Draws information from several types of studies and reports* Helps readers answer questions about the most appropriate materials and when to use them

Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 772

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Author: Laëtitia Salou
Publisher:
ISBN:
Category :
Languages : en
Pages : 212

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Book Description
Biocompatible and corrosion resistant regarding biological fluids, titanium is still an inert material: it does not participate actively at the tissue-integration around the implant. Surface modification of titanium at nanoscale can promote cell adhesion and differentiation by modulate genes expression due to a phenomenon of mechano-transduction. In this thesis, we have focused on the development, the characterization and the direct application of our nanostructured surface of medical devices. First of all, our study focused on the preparation and physicochemical characterization. After obtaining reproducible surfaces on small samples, our research has focused on the biological characterization of the surface. In-vivo studies conducted in rabbits have allowed us to show similar biomechanical attachment and good osseointegration of the nanostructured surface compared to commonly used surfaces on the market. The application of this new surface on more complex titanium implant such as tracheal prosthesis, has allowed us to observe delamination phenomenon of the nanostructure layer. Therefore, our research was oriented towards the problem of mechanical strength of the surface with the realization of nano scratch test and tribology. A topic in the zeitgeist, as a new EU regulation for medical devices which incorporate nanomaterials will take effect in 2017. To conclude, this work enable to propose a nanosurface with promising results of tissues integration required for medical device.

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

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Book Description
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: Mohammad Mohsin Hossain
Publisher:
ISBN:
Category : Titanium alloys
Languages : en
Pages : 538

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Book Description
Titanium-based engineering materials are currently considered to be the best artificial implant materials because of their good mechanical strength, resistance to corrosion, and their nontoxic compatibility with the stable oxide, TiO2. Ti6Al4V alloy is biologically inert, showing limited interaction with human tissue to their native oxide surface, which generally results in mechanical fixation. If the material is able to interact directly with tissue through chemical bonding, thus leading to a bioactive fixation, this will make a better and stronger implant for the promotion of cell attachment and migration and bone growth. Surface modification can improve the properties of surface oxide, leading to the formation of a stable oxide layer on the alloy's surface, and thus resulting in greater bioactivity. Surface modification is performed through surface chemical treatments, coatings deposition and chemical and thermal oxidation at a variety of process temperatures. The acid-alkaline-treated surface shows rougher, higher wettability and the presence of oxide of TiO2, as per the averaged results. In a comparison of roughness, wettability, and surface chemistry, no differences are observed between the original and solvent-treated surfaces. The crystalline structure of the surface treated samples reveals alpha and beta phases of Ti6Al4V alloy. However, the alpha 110 peak has only appeared on acid-alkaline substrate. This appearance is probably caused by a change of orientation of the crystallographic plane. Bioactivity results show no differences in Ca-P deposition between the surfaces, leading to CaHPO4, Ca/P~1.0. Some clusters deposit only on the original and solvent-treated surfaces which contain higher Ca-P than the surfaces in the non-cluster region, as observed by SEMEDS. Chemical oxidation treatments are conducted on the original surfaces by the H2O2, 37°C and H2O2, 80°C. Crystalline phases are generally associated with titanium alpha-beta, and a few with anatase and rutile. All the oxidised surfaces are defected by the presence of pores. Ti peaks are seen on the surfaces oxidised by H2O2, 37°C but no longer seen on the surfaces oxidised by H2O2, 80°C, except on the oxidised original surface. TiO2 concentrations are found quantitatively in the Ti 2p and O 1s spectra. A hydroxyl-rich oxides concentration is found at similar levels on all the oxidised surfaces. The oxidised acid-alkaline surface appears to be rougher than the other oxidised surfaces but the effects on the surface hydrophilicity are similar. Bioactivity results show a higher concentration of Ca-P deposits, leading to hydroxyapatite, Ca/P~1.6±0.1. The Ca-P deposition in SBF is increased from 3 to 14 days, as observed by XPS. Thick cluster layers are observed on the oxidised surfaces of the samples incubated for 14 days; these are composed of O, Ca and P; Ca/P~1.5, as observed by SEMEDS. Coating depositions of Ti and TiO2 are performed on the solvent-treated surface. XPS results show no Ti peaks present on the TiO2-deposited surface. The TiO2-deposited surface appears to be rougher and less hydrophilic than other surfaces. No significantly different Ca-P depositions are found on the deposited surfaces as results of CaHPO4 and Ca/P~1.0, which do not exhibit a good bioactive response. The chemically oxidised surfaces show a similarly roughened effect on all the oxidised surfaces. The oxidised Ti- and TiO2-deposited surfaces appear to be more hydrophilic than the oxidised solvent-treated alloys. The chemically oxidised surfaces reveal that Ca-P depositions increase, leading to hydroxyapatite, Ca/P~1.6±0.1 and that there are no differences in the oxidised deposited surfaces of any of the samples incubated from between 3 to 14 days. The Ca-P depositions on the oxidised deposited surfaces are found to have almost half the value of those on the oxidised solventtreated surfaces. The effects of thermal and chemical oxidation on the Ti-deposited samples are investigated. The crystalline structure is transformed from anatase to rutile in an increasing thermal temperature treatment of up to 800°C. At higher magnification, a thin layer with a porous structure is observed on the chemically oxidised surfaces. Shiny oxide layers are seen on the thermally oxidised surfaces. The concentration of atomic oxygen increases as the thermal temperature is increased from 100°C to 800°C, as observed by EDS. The surface chemistry results show that the content of chemically and thermally oxidised surfaces comprises hydroxyl-rich oxides and hydroxyl-poor oxides, respectively. Bioactivity results show that the chemically oxidised surface is able to deposit more Ca-P, leading to the formation of hydroxyapatite, Ca/P~1.7±0.1. However, the thermally oxidised surfaces deposit Ca(H2PO4)2 and, CaCO3 and P2O5 at temperatures of 100°C, 400°C and 800°C, respectively, at Ca/P~0.5. It has been conclusively proved that Ca-P depositions are dependent on the presence of hydroxyl-rich oxides. Apatite nucleation can be formally initiated at the stage of the completion of Ca-P depositions and can actively promote bone-growth after the material has been implanted.

Author: Parisi Ludovica
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Background: Implants osseointegration is affected by cell responses at the bone-implant interface, which depends on the chemical composition,micro topography and wettability of the surface, which, in turn, influence protein adsorption.Aim: To investigate whether hyperhydrophilicity alters surface selectivity for fibronectin, a protein which plays a pivotal role in cell adhesionand proliferation.Materials and Methods: Acid-etched sandblasted surfaces were treated through a proprietary process in order to obtain hyper-hydrophilic surfaces. Surfacefeatures were characterized by X-Ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and themeasurement of the contact angle. Protein adsorption was assessed by SDS-PAGE analysis, and the influence of surface infibronectin adsorption was assayed through Western Blot. Cell attachment to the surfaces was then studied. Murine osteoblastsMC3T3-E1 cells were cultured for 24 hours in complete medium. Their morphology and adhesion were studied through theimmuno-staining for cytoskeleton and for focal adhesions and through the use of SEM microscopy coupled to Focused Ion Beam(FIB). FIB analysis allowed to cut cells during SEM observation and to investigate their interactions with the surface. Furthermore, celladhesion was assessed by quantitating the amount of attached cells to the surface at different experimental points through achemiluminescence assay.Results: Our results showed that the experimental treatment induced a gain of titanium hydrophilicity, without inducing any modification inchemical composition or topography. SDS-PAGE revealed a great amount of proteins adsorbed on treated surfaces, while WesternBlot indicated that hydrophilicity increased the amount of fibronectin adsorbed on the surface.Moreover, hyper-hydrophilic surfaces allowed a closer adhesion of cells. Immuno-staining revealed healthy cells on both surfaces,however cells growing on hydrophilic surfaces expressed a higher amount of focal adhesions. Similarly, the adhesion curve showed afaster cell adhesion to hydrophilic titanium already after 30 minutes of culture. SEM-FIB analysis demonstrated that cells on untreatedsurfaces adhered preferentially to the micro texture peaks, while hyper-hydrophilicity promotes the adhesion of cell body to the peaksthroughout the sample. Cells appeared thinner and spread on the entire surface.Conclusions: Taken together, our data show that hyper-hydrophilicity affects protein adsorption. In particular, we observed a more selectiveadsorption of fibronectin, which may be responsible for improved cell adhesion to micro-patterned titanium.

Author: Wisanu Boonrawd
Publisher:
ISBN:
Category : Biomedical engineering
Languages : en
Pages : 104

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Book Description
Electrolytic plasma processing (EPP) can be operated in two modes, namely plasma electrolytic saturation (PES) and plasma electrolytic oxidation (PEO). In this study, the PES was used to create hydrophilic surface profiles on titanium (Ti). The wettability, surface morphology characteristics and chemical composition of the treated samples were studi650ed as a function of PES processing parameters. The PES profiled surfaces comprised of a characteristic "hills and valleys" morphology because of continuous surface melting and freezing cycles. A bimodal surface profile was produced with 2-3 μm height hills and valleys with nano-roughness (≤ 200 nm). The produced profile resulted in a significant contact angle decrease (from 38.7° to 5.4°). Ratios of actual surface area to projection area (r) and fraction of solid surface remaining dry (j) were obtained from profilometry. The surface characteristics and large r values produced by PES were able to induce hemi-wicking. Hence, PES produced superhydrophilic surfaces on Ti. The bioactivity of PES treated Ti was evaluated using cell free and MC3T3 cells in-vitro studies. The treatedi surface significantly increased the bioactivity and formed stoichiometric hydroxyapatite after immersion in a bone cell culture medium for 21 days. Cells' attachment and proliferation studies indicated that PES treated surface significantly enhances the cells' adhesion and growth after 24 and 48 hr compared to the untreated surface. The results show that Ti surface profiling by PES constitutes a promising method to potentially improve bone implant bonding. PEO was used to produce titanium oxide (TiO2) coatings on Ti surface in potassium -phosphate electrolyte. The morphology, wettability, phase, and chemical compositions were studied as a function of processing parameters. The bioactivity of the coating was assessed by the ability to form biomimetic apatite in-vitro using cell culture medium. In-vitro studies using human mesenchymal stem cells were also conducted to evaluate cells' proliferation and viability of the treated Ti. The results revealed that the produced TiO2 coatings comprised pore features with the pore size increasing with applied current density and treatment duration due to high energy discharge channels at higher potential. The PEO treated Ti exhibited superhydrophilic characteristics with a contact angle

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

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Book Description