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Thomas J Webster - One of the best experts on this subject based on the ideXlab platform.
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Orthopedic Implant biomaterials with both osteogenic and anti infection capacities and associated in vivo evaluation methods
Nanomedicine: Nanotechnology Biology and Medicine, 2017Co-Authors: Shaofeng Yang, Thomas J Webster, Huilin Yang, Lei YangAbstract:Abstract Osteogenicity (i.e., properties that promote new bone formation on and around the Implant) has long been a clinical requirement for most Orthopedic Implants. Recently, anti-infection or antibacterial properties have become critical for Orthopedic Implants (especially without the use of antibiotics). Ideally, Orthopedic Implant materials with simultaneous anti-infection and osteogenic capacities are extremely promising for Orthopedic applications, but such materials are not widely available to date and have only recently been researched. In the first part of this review, numerous attractive material formulations that exhibit both antibacterial and osteogenic capacities as well as surface modification strategies that enhance such capacities are introduced. Several possible mechanisms underlying simultaneous antibacterial and osteogenic properties are also discussed. In the second part of this review, evaluation methods including animal models, analytical tools and available guidelines for assessing antibacterial and osteogenic properties of Implantable materials in vivo are summarized and discussed.
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Functionalized nanophase hydroxyapatite (HA) for Orthopedic applications
2014 40th Annual Northeast Bioengineering Conference (NEBEC), 2014Co-Authors: Garima Bhardwaj, Thomas J WebsterAbstract:Orthopedic Implants fail due to various reasons such as extensive bacterial colonization, poor osseointegration, extensive inflammation and osteolysis due to wear debris. In order to reduce Orthopedic Implant failures, the main objective of this study was to create a biomimetic bone tissue engineering material based on the osteoconductive properties of nanophase hydroxyapatite (HA), the bacterial inhibition properties of the MAM7 peptide1, the quorum sensing inhibitor RNAIII peptide2, and the anticancer properties of the PCK3145 peptide3 as well as curcumin4. Results showed promise for these materials to combat common failure modes of Orthopedic Implants.
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nanostructured titanium the ideal material for improving Orthopedic Implant efficacy
Nanomedicine: Nanotechnology Biology and Medicine, 2012Co-Authors: Naside Gozde Durmus, Thomas J WebsterAbstract:Titanium (Ti) and its alloys have been widely used as Implant materials for Orthopedic applications owing to their excellent wear, corrosion resistance, light weight but strong mechanical and acceptable biocompatibility properties. However, such Implants still widely experience lifetimes of less than 20 years owing to a variety of reasons eventually leading to Implant separation from bone. In 1999, Webster et al. provided the first evidence that osteoblast (bone-forming cells) adhesion and bone formation significantly increases on nanostructured titania compared with conventional titania [1]. Since then, nanotechnology (or the use of materials with dimensions less than 100 nm in at least 1D) have been proposed to improve the quality of Orthopedic Implants by better mimicking the nanoscale properties of native bone tissue.
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greater osteoblast long term functions on ionic plasma deposited nanostructured Orthopedic Implant coatings
Journal of Biomedical Materials Research Part A, 2008Co-Authors: Alex Reising, Dan Storey, Thomas J WebsterAbstract:Bioactive coatings are in high demand to increase the functions of cells for numerous medical devices. The objective of this in vitro study was to characterize for the first time osteoblast (bone-forming cell) long-term functions (such as proliferation and deposition of calcium containing mineral) on several potential Orthopedic Implant polymeric materials [specifically, ultrahigh molecular weight polyethylene (UHMWPE) and polytetrafluoroethylene (PTFE)] coated with nanostructured titanium using a novel ionic plasma deposition (IPD) coating process. UHMWPE is a widely used polymer in total knee and hip replacements, while PTFE is not, but it has been used in other Orthopedic applications. The IPD coating process creates a surface-engineered nanostructure (with features usually below 100 nm) by first using a vacuum to remove all contaminants, and then guiding charged metallic ions or plasma to the surface of a medical device at ambient temperature. Results demonstrated that compared to currently used titanium and uncoated polymers, polymers coated with titanium using IPD significantly increased osteoblast proliferation and, most importantly, calcium deposition. In this manner, this study strongly suggests that IPD should be further studied for creating nanometer titanium surface feature coatings to enhance osteoblast functions necessary to increase Orthopedic Implant efficacy. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
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Novel anti-cancer Orthopedic materials: Nanostructured selenium
2007 IEEE 33rd Annual Northeast Bioengineering Conference, 2007Co-Authors: Phong Tran, Thomas J WebsterAbstract:Metallic bone Implants possess numerous problems limiting their efficacy, such as poor osseointegration, stress shielding, and corrosion in in vivo environments. In addition, these materials were not originally developed to simultaneously serve as an Orthopedic Implant and treat bone cancer (for which some patients require an Orthopedic Implant). This study is to investigate the potential use of selenium in bone Implants to prevent bone cancer from re-occurring and support new bone growth. For this, selenium, spherical or semispherical shots, were etched using NaOH to obtain various surface structures ranging from the micron, sub micron to nano scales. Through these etching techniques, biologically inspired surface roughness values were created on selenium to match that of natural bone. In this manner, this study suggests a promising future for nanostructured selenium in Orthopedic applications involving bone cancer treatment.
Carla Renata Arciola - One of the best experts on this subject based on the ideXlab platform.
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Orthopedic Implant infections incompetence of staphylococcus epidermidis staphylococcus lugdunensis and enterococcus faecalis to invade osteoblasts
Journal of Biomedical Materials Research Part A, 2016Co-Authors: Davide Campoccia, Lucio Montanaro, Stefano Ravaioli, Ilaria Cangini, Pietro Speziale, Livia Visai, Francesca Testoni, Alessandra Maso, Carla Renata ArciolaAbstract:Septic failure is still the major complication of prosthetic Implants. Entering host cells, bacteria hide from host immune defenses, shelter from extracellular antibiotics, and cause chronic infection. Staphylococcus aureus, the leading etiologic agent of Orthopedic Implant infections, is able to enter bone cells and induce osteoblast apoptosis, osteoclast recruitment, and highly destructive osteomyelitis. Staphylococcus epidermidis, Staphylococcus lugdunensis, and Enterococcus faecalis are opportunistic pathogens causative of Implant-related infections. This study investigated the ability to internalize into osteoblastic MG63 cells of 22 S. epidermidis, 9 S. lugdunensis, and 21 E. faecalis clinical isolates from Orthopedic Implant infections. Isolates were categorized in clusters by ribotyping. Internalization assay was carried out by means of a microtiter plate-based method. S. epidermidis, S. lugdunensis, and E. faecalis strains turned out incompetent to enter osteoblasts, exhibiting negligible internalization into MG63 cells, nearly three orders of magnitude lower than that of S. aureus. Osteoblast invasion does not appear as a pathogenetic mechanism utilized by S. epidermidis, S. lugdunensis, or E. faecalis for infecting Orthopedic Implants. Moreover, it can be inferred that intracellularly active antimicrobials should not be necessary against Implant infections caused by the three bacterial species. Finally, implications with the uptake of biomaterial microparticles by nonphagocytic cells are enlightened. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 788–801, 2016.
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Polymorphisms of agr locus correspond to distinct genetic patterns of virulence in Staphylococcus aureus clinical isolates from Orthopedic Implant infections
Journal of Biomedical Materials Research - Part A, 2010Co-Authors: Lucio Montanaro, Valter Pirini, Stefano Ravaioli, Ilaria Cangini, Pietro Speziale, Davide Campoccia, Livia Visai, Carla Renata ArciolaAbstract:Staphylococcus aureus is the leading etiologic agent of Orthopedic Implant infections. It is endowed with the accessory gene regulator (agr) locus that modulates expression of many virulence genes. Four allelic groups of agr have been recognized within this bacterial species. Here, 200 S. aureus isolates from Orthopedic Implant infections, typed at the start depending on their agr group, were screened for the presence of adhesin and leukotoxin genes. Interestingly, specific virulence gene patterns emerged in association with agr groups. The most frequently observed agr groups, agr I and agr II, were associated with the presence of sdrE, fib (agr II more than agr I), fnbB (agr I more than agr II), and lukE/lukD (agr II more than agr I). The third more frequent agr group, agr III, differed clearly from agr I and II, exhibiting high prevalence of bbp, generally not harbored by agr I and II, and copresence of bbp with cna, whereas high prevalence of the tandem sdrE/fib marked definitely agr II (91% of agr II isolates), and, though less strictly, agr I, in which prevailed the peculiar fib/fnbB pattern. The only four isolates belonging to agr IV showed full copresence of bbp with fib. Results point out distinct patterns of virulence genes, which underlie distinct evolutive strategies associated to agr groups in S. aureus causing Orthopedic Implant infections.
Lucien Reclaru - One of the best experts on this subject based on the ideXlab platform.
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pitting crevice and galvanic corrosion of rex stainless steel cocr Orthopedic Implant material
Biomaterials, 2002Co-Authors: Lucien Reclaru, R Lerf, P Y Eschler, Andreas Blatter, J.-m. MeyerAbstract:Abstract The corrosion behavior of surgical Implant CoCr alloy and REX 734 steel has been investigated. The pitting or crevice corrosion potentials have been determined to reach values as high as 500 mV vs. SCE for CoCr and 450 mV vs. SCE for REX 734. The galvanic corrosion behavior of CoCr/REX 734 couples has been evaluated with various electrochemical techniques. The measurement of the corrosion current of the galvanic couple as well as its prediction by applying mixed potential theories on measured potentiodynamic polarization curves revealed low galvanic currents in the range of nanoamperes.
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corrosion behavior of a welded stainless steel Orthopedic Implant
Biomaterials, 2001Co-Authors: Lucien Reclaru, R Lerf, P Y Eschler, Jeanmarc MeyerAbstract:Abstract The corrosion behavior of combinations of materials used in an Orthopedic Implant: the spherical part (forged or forged and annealed) constituting the head, the weld (tungsten inert gas (TIG) or electron beam (EB) techniques), and the cylindrical part (annealed) constituting the shaft of a femoral prosthesis – has been investigated. Open-circuit potentials, potentiodynamic curves, Tafel slope, mixed potential theory and susceptibility to intergranular attack are electrochemical and chemical procedures selected for this work. Electrochemical measurements using a microelectrode have been made in the following zones: spherical part, cylindrical part, weld, and weld/sphere, and weld/shaft interfaces. To detect intergranular attack, the Strauss test has been used. At the interfaces, corrosion currents, measured ( I corr ) and predicted ( I couple ) are low, in the order of the pico- to nanoampere. The electrochemical behavior of the electron beam (EB) weld is better than that of the tungsten inert gas (TIG). Welds at interfaces can behave either anodically or cathodically. It is better if welds, which are sensitive parts of the femoral prosthesis, behave cathodically. In this way, the risk of starting localized corrosion (pitting, crevice or intergranular corrosion) from a galvanic couple, remains low. From this point of view, the sample with the EB weld offers the best behavior. All the other samples containing a TIG type of weld exhibit a less favorable behavior. The mechanical treatments (forged, and forged and annealed) of the steel sphere did not show any difference in the corrosion behavior. No intergranular corrosion has been observed at the weld/steel interface for unsensitized samples. With sensitized samples, however, a TIG sample has exhibited some localized intergranular corrosion at a distance of 500 μm along the weld/stainless steel (sphere) interface.
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Corrosion behavior of a welded stainless-steel Orthopedic Implant
Biomaterials, 2001Co-Authors: Lucien Reclaru, R Lerf, P Y Eschler, J.-m. MeyerAbstract:The corrosion behavior of combinations of materials used in an Orthopedic Implant: the spherical part (forged or forged and annealed) constituting the head, the weld (tungsten inert gas (TIG) or electron beam (EB) techniques), and the cylindrical part (annealed) constituting the shaft of a femoral prosthesis - has been investigated. Open-circuit potentials, potentiodynamic curves, Tafel slope, mixed potential theory and susceptibility to intergranular attack are electrochemical and chemical procedures selected for this work. Electrochemical measurements using a microelectrode have been made in the following zones: spherical part, cylindrical part, weld, and weld/sphere, and weld/shaft interfaces. To detect intergranular attack, the Strauss test has been used. At the interfaces, corrosion currents, measured (I(corr)) and predicted (I(couple)) are low, in the order of the pico- to nanoampere. The electrochemical behavior of the electron beam (EB) weld is better than that of the tungsten inert gas (TIG). Welds at interfaces can behave either anodically or cathodically. It is better if welds, which are sensitive parts of the femoral prosthesis, behave cathodically. In this way, the risk of starting localized corrosion (pitting, crevice or intergranular corrosion) from a galvanic couple, remains low. From this point of view, the sample with the EB weld offers the best behavior. All the other samples containing a TIG type of weld exhibit a less favorable behavior. The mechanical treatments (forged, and forged and annealed) of the steel sphere did not show any difference in the corrosion behavior. No intergranular corrosion has been observed at the weld/steel interface for unsensitized samples. With sensitized samples, however, a TIG sample has exhibited some localized intergranular corrosion at a distance of 500μm along the weld/stainless steel (sphere) interface. Copyright (C) 2000 Elsevier Science Ltd.
Davide Campoccia - One of the best experts on this subject based on the ideXlab platform.
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Orthopedic Implant infections incompetence of staphylococcus epidermidis staphylococcus lugdunensis and enterococcus faecalis to invade osteoblasts
Journal of Biomedical Materials Research Part A, 2016Co-Authors: Davide Campoccia, Lucio Montanaro, Stefano Ravaioli, Ilaria Cangini, Pietro Speziale, Livia Visai, Francesca Testoni, Alessandra Maso, Carla Renata ArciolaAbstract:Septic failure is still the major complication of prosthetic Implants. Entering host cells, bacteria hide from host immune defenses, shelter from extracellular antibiotics, and cause chronic infection. Staphylococcus aureus, the leading etiologic agent of Orthopedic Implant infections, is able to enter bone cells and induce osteoblast apoptosis, osteoclast recruitment, and highly destructive osteomyelitis. Staphylococcus epidermidis, Staphylococcus lugdunensis, and Enterococcus faecalis are opportunistic pathogens causative of Implant-related infections. This study investigated the ability to internalize into osteoblastic MG63 cells of 22 S. epidermidis, 9 S. lugdunensis, and 21 E. faecalis clinical isolates from Orthopedic Implant infections. Isolates were categorized in clusters by ribotyping. Internalization assay was carried out by means of a microtiter plate-based method. S. epidermidis, S. lugdunensis, and E. faecalis strains turned out incompetent to enter osteoblasts, exhibiting negligible internalization into MG63 cells, nearly three orders of magnitude lower than that of S. aureus. Osteoblast invasion does not appear as a pathogenetic mechanism utilized by S. epidermidis, S. lugdunensis, or E. faecalis for infecting Orthopedic Implants. Moreover, it can be inferred that intracellularly active antimicrobials should not be necessary against Implant infections caused by the three bacterial species. Finally, implications with the uptake of biomaterial microparticles by nonphagocytic cells are enlightened. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 788–801, 2016.
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Polymorphisms of agr locus correspond to distinct genetic patterns of virulence in Staphylococcus aureus clinical isolates from Orthopedic Implant infections
Journal of Biomedical Materials Research - Part A, 2010Co-Authors: Lucio Montanaro, Valter Pirini, Stefano Ravaioli, Ilaria Cangini, Pietro Speziale, Davide Campoccia, Livia Visai, Carla Renata ArciolaAbstract:Staphylococcus aureus is the leading etiologic agent of Orthopedic Implant infections. It is endowed with the accessory gene regulator (agr) locus that modulates expression of many virulence genes. Four allelic groups of agr have been recognized within this bacterial species. Here, 200 S. aureus isolates from Orthopedic Implant infections, typed at the start depending on their agr group, were screened for the presence of adhesin and leukotoxin genes. Interestingly, specific virulence gene patterns emerged in association with agr groups. The most frequently observed agr groups, agr I and agr II, were associated with the presence of sdrE, fib (agr II more than agr I), fnbB (agr I more than agr II), and lukE/lukD (agr II more than agr I). The third more frequent agr group, agr III, differed clearly from agr I and II, exhibiting high prevalence of bbp, generally not harbored by agr I and II, and copresence of bbp with cna, whereas high prevalence of the tandem sdrE/fib marked definitely agr II (91% of agr II isolates), and, though less strictly, agr I, in which prevailed the peculiar fib/fnbB pattern. The only four isolates belonging to agr IV showed full copresence of bbp with fib. Results point out distinct patterns of virulence genes, which underlie distinct evolutive strategies associated to agr groups in S. aureus causing Orthopedic Implant infections.
J.-m. Meyer - One of the best experts on this subject based on the ideXlab platform.
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pitting crevice and galvanic corrosion of rex stainless steel cocr Orthopedic Implant material
Biomaterials, 2002Co-Authors: Lucien Reclaru, R Lerf, P Y Eschler, Andreas Blatter, J.-m. MeyerAbstract:Abstract The corrosion behavior of surgical Implant CoCr alloy and REX 734 steel has been investigated. The pitting or crevice corrosion potentials have been determined to reach values as high as 500 mV vs. SCE for CoCr and 450 mV vs. SCE for REX 734. The galvanic corrosion behavior of CoCr/REX 734 couples has been evaluated with various electrochemical techniques. The measurement of the corrosion current of the galvanic couple as well as its prediction by applying mixed potential theories on measured potentiodynamic polarization curves revealed low galvanic currents in the range of nanoamperes.
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Corrosion behavior of a welded stainless-steel Orthopedic Implant
Biomaterials, 2001Co-Authors: Lucien Reclaru, R Lerf, P Y Eschler, J.-m. MeyerAbstract:The corrosion behavior of combinations of materials used in an Orthopedic Implant: the spherical part (forged or forged and annealed) constituting the head, the weld (tungsten inert gas (TIG) or electron beam (EB) techniques), and the cylindrical part (annealed) constituting the shaft of a femoral prosthesis - has been investigated. Open-circuit potentials, potentiodynamic curves, Tafel slope, mixed potential theory and susceptibility to intergranular attack are electrochemical and chemical procedures selected for this work. Electrochemical measurements using a microelectrode have been made in the following zones: spherical part, cylindrical part, weld, and weld/sphere, and weld/shaft interfaces. To detect intergranular attack, the Strauss test has been used. At the interfaces, corrosion currents, measured (I(corr)) and predicted (I(couple)) are low, in the order of the pico- to nanoampere. The electrochemical behavior of the electron beam (EB) weld is better than that of the tungsten inert gas (TIG). Welds at interfaces can behave either anodically or cathodically. It is better if welds, which are sensitive parts of the femoral prosthesis, behave cathodically. In this way, the risk of starting localized corrosion (pitting, crevice or intergranular corrosion) from a galvanic couple, remains low. From this point of view, the sample with the EB weld offers the best behavior. All the other samples containing a TIG type of weld exhibit a less favorable behavior. The mechanical treatments (forged, and forged and annealed) of the steel sphere did not show any difference in the corrosion behavior. No intergranular corrosion has been observed at the weld/steel interface for unsensitized samples. With sensitized samples, however, a TIG sample has exhibited some localized intergranular corrosion at a distance of 500μm along the weld/stainless steel (sphere) interface. Copyright (C) 2000 Elsevier Science Ltd.
