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Jackie Y Ying - One of the best experts on this subject based on the ideXlab platform.
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the development of a nanocrystalline apatite reinforced crosslinked hyaluronic acid tyramine composite as an injectable Bone Cement
Biomaterials, 2009Co-Authors: Motoichi Kurisawa, Joo Eun Chung, Jackie Y YingAbstract:We have developed an injectable Bone Cement composed of nanocrystalline apatite and crosslinked hyaluronic acid–tyramine conjugates (HA–Tyr). This Bone Cement was formed via the oxidative coupling of tyramine moieties catalyzed by hydrogen peroxide (H2O2) and horseradish peroxidise (HRP). The Bone Cement set within 60 s after H2O2 and HRP were added to the apatite/HA–Tyr pastes. The mechanical strength of the apatite/HA–Tyr Cement was tuned by varying the apatite loading and H2O2 concentration. This rapid enzyme-mediated setting of our Bone Cement results in minimal heat release (DH ¼� 11.39 J/g) as compared to conventional Bone Cements. The crystalline phase and crystallite size (20 nm) of the apatitic phase in our Bone Cement matched that of trabecular Bone. The storage modulus (G 0 ), yield stress (sy), and compressive stiffness (Ec) of our Bone Cement prepared with different apatite loadings and H2O2 concentrations were measured, and optimized at G
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the development of a nanocrystalline apatite reinforced crosslinked hyaluronic acid tyramine composite as an injectable Bone Cement
Biomaterials, 2009Co-Authors: Shona Y Pek, Motoichi Kurisawa, Joo Eun Chung, Shujun Gao, Jackie Y YingAbstract:We have developed an injectable Bone Cement composed of nanocrystalline apatite and crosslinked hyaluronic acid-tyramine conjugates (HA-Tyr). This Bone Cement was formed via the oxidative coupling of tyramine moieties catalyzed by hydrogen peroxide (H(2)O(2)) and horseradish peroxidase (HRP). The Bone Cement set within 60s after H(2)O(2) and HRP were added to the apatite/HA-Tyr pastes. The mechanical strength of the apatite/HA-Tyr Cement was tuned by varying the apatite loading and H(2)O(2) concentration. This rapid enzyme-mediated setting of our Bone Cement results in minimal heat release (DeltaH=-11.39 J/g) as compared to conventional Bone Cements. The crystalline phase and crystallite size (20 nm) of the apatitic phase in our Bone Cement matched that of trabecular Bone. The storage modulus (G'), yield stress (sigma(y)), and compressive stiffness (E(c)) of our Bone Cement prepared with different apatite loadings and H(2)O(2) concentrations were measured, and optimized at G'=40 MPa, sigma(y)=0.308 MPa and E(c)=2.270 MPa when the Cement was formed with 0.4 g/ml of apatite, 0.61 units/ml of HRP and 6.8 mm of H(2)O(2). Our biocompatible Bone Cement also successfully healed small Bone and joint defects in mice within 8 weeks.
Nicholas Dunne - One of the best experts on this subject based on the ideXlab platform.
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in vitro testing of chitosan in gentamicin loaded Bone Cement no antimicrobial effect and reduced mechanical performance
Acta Orthopaedica, 2008Co-Authors: Nicholas Dunne, M M Tunney, Aaron Brady, Fraser Buchanan, Caroline Newe, Janet E Hill, Gavin WalkerAbstract:Background and purpose Efforts to prevent infection of arthroplasties, including the use of antibiotic-loaded Bone Cement, are not always successful. We investigated whether the incorporation of chitosan in gentamicin-loaded Bone Cement increases antibiotic release, and prevents bacterial adherence and biofilm formation by clinical isolates of Staphylococcus spp. In addition, we performed mechanical and degradation tests.Methods Different amounts of chitosan were added to the powder of the gentamicin-loaded Bone Cement. Gentamicin release was determined using high-per-formance liquid chromatography mass spectrometry. Bacterial adherence and bacterial biofilm formation were determined using clinical isolates cultured from implants retrieved at revision hip surgery. The mechanical properties were determined as a function of degradation in accordance with ISO and ASTM standards for PMMA Bone Cement.Results The addition of chitosan to Bone Cement loaded with gentamicin reduced gentamicin release and did not i...
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In vitro study investigating the mechanical properties of acrylic Bone Cement containing calcium carbonate nanoparticles
Journal of Materials Science: Materials in Medicine, 2008Co-Authors: Janet Hill, Nicholas DunneAbstract:A successful total hip replaCement has an expected service life of 10–20 years with over 75% of failures due to aseptic loosening which is directly related to Cement mantle failure. The aim of the present study was to investigate the addition of nanoparticles of calcium carbonate to acrylic Bone Cement. It was anticipated that an improvement in mechanical performance of the resultant nanocomposite Bone Cement would be achieved. A design of experiment approach was adopted to maximise the mechanical properties of the Bone Cement containing nanoparticles of calcium carbonate and to determine the constituents and preparation methods for which these occur. The selected conditions provided improvements of 21% in energy to maximum load, 10% in elastic modulus, 7% in bending strength and 8% in bending modulus when compared with Bone Cement without nanoparticles. Although Cement containing nanoCaCO_3 coated in sodium citrate also enhanced the energy to maximum load by 28% and the elastic modulus by 14% when compared with control Cement, it is not recommended as a factor in the production of nanocomposite Bone Cement due to reduction in the bending properties of the final Bone Cement.
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incorporation of chitosan in acrylic Bone Cement effect on antibiotic release bacterial biofilm formation and mechanical properties
Journal of Materials Science: Materials in Medicine, 2008Co-Authors: M M Tunney, Aaron Brady, Fraser Buchanan, Caroline Newe, Nicholas DunneAbstract:Bacterial infection remains a significant problem following total joint replaCement. Efforts to prevent recurrent implant infection, including the use of antibiotic-loaded Bone Cement for implant fixation at the time of revision surgery, are not always successful. In this in vitro study, we investigated whether the addition of chitosan to gentamicin-loaded Palacos® R Bone Cement increased antibiotic release and prevented bacterial adherence and biofilm formation by Staphylococcus spp. clinical isolates. Furthermore, mechanical tests were performed as a function of time post-polymerisation in pseudo-physiological conditions. The addition of chitosan to gentamicin-loaded Palacos® R Bone Cement significantly decreased gentamicin release and did not increase the efficacy of the Bone Cement at preventing bacterial colonisation and biofilm formation. Moreover, the mechanical performance of Cement containing chitosan was significantly reduced after 28 days of saline degradation with the compressive and bending strengths not in compliance with the minimum requirements as stipulated by the ISO standard for PMMA Bone Cement. Therefore, incorporating chitosan into gentamicin-loaded Palacos® R Bone Cement for use in revision surgery has no clinical antimicrobial benefit and the detrimental effect on mechanical properties could adversely affect the longevity of the prosthetic joint.
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development of operator independent Bone Cement vacuum mixing system for joint replaCement surgery
Plastics Rubber and Composites, 2006Co-Authors: Nicholas Dunne, C Daly, Jonathan E Makem, Gavin Walker, John OrrAbstract:Acrylic Bone Cement is weakened by its porosity, which promotes the formation of microcracks, which contribute to major crack propagation and ultimately failure of the Cement mantle. Bone Cement mixing techniques play a significant role in determining the quality of Bone Cement produced. A high degree of porosity is found to exist in Cement that is inadequately mixed. Current commercial Bone Cement mixing systems allow for the preparation of the Bone Cement under the application of a vacuum in a closed, sealed chamber by means of a repeatable mixing action. These mixing systems are perceived to be repeatable and reliable by orthopaedic community. In this paper, the quality of Bone Cement mixed using an operator independent Bone Cement mixing system was compared with that of Cement prepared using commercially available devices. The results of the investigation highlighted that Cement prepared using the automated, repeatable mixing regime that is operator independent demonstrated consistently better physical and mechanical properties in comparison with Cement mixed using proprietary Cement mixing devices. Furthermore, Design of Experiments software established the optimal factors that influenced the physical and mechanical properties of PMMA Bone Cement.
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influence of mixing techniques on the physical properties of acrylic Bone Cement
Biomaterials, 2001Co-Authors: Nicholas Dunne, John OrrAbstract:Palacos R Bone Cement was prepared using three commercially available mixing techniques, first generation, second generation and third generation, to determine the mechanical properties and porosity contents of the Bone Cement. The compressive strengths, bending strengths and flexural moduli were expressed as a function of void content. The volume of pores within the Cement structure was found to be a contributing factor to the physical properties of acrylic Bone Cement. The lower the volume of voids in the Cement the better the compressive and flexural properties, hence stronger Bone Cement. It was found that the best results were obtained from Cement that had been mixed using the Mitab Optivac or Summit HiVac Syringe systems at a reduced pressure level of between -72 and -86 kPa below atmospheric pressure, resulting in Cement of porosity 1.44-3.17%; compressive strength 74-81 MPa; flexural modulus 2.54-2.60 GPa; and flexural strength 65-73 MPa.
William M. Reichert - One of the best experts on this subject based on the ideXlab platform.
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extended fatigue life of a catalyst free self healing acrylic Bone Cement using microencapsulated 2 octyl cyanoacrylate
Journal of Biomedical Materials Research Part B, 2015Co-Authors: Alice B. W. Brochu, Oriane B. Matthys, Stephen L. Craig, William M. ReichertAbstract:The tissue adhesive 2-octyl cyanoacrylate (OCA) was encapsulated in polyurethane microshells and incorporated into Bone Cement to form a catalyst free, self-healing Bone Cement comprised of all clinically approved components. The bending strength, modulus, and fatigue lifetime were investigated in accordance with ASTM and ISO standards for the testing of PMMA Bone Cement. The bending strength of Bone Cement specimens decreased with increasing wt % capsules content for capsules without or with OCA, with specimens of <5 wt % capsule content showing minimal effect. In contrast, Bone Cement bending modulus was insensitive to capsule content. Load controlled fatigue testing was performed in air at room temperature on capsule free Bone Cement (0 wt %), Bone Cement with 5 wt % OCA-free capsules (5 wt % No OCA), and 5 wt % OCA-containing capsules (5 wt % OCA). Specimens were tested at a frequency of 5 Hz at maximum stresses of 90%, 80%, 70%, and 50% of each specimen's bending strength until failure. The 5 wt % OCA exhibited significant self-healing at 70% and 50% of its reference strength (p < 0.05). Fatigue testing of all three specimen types in air at 22 MPa (50% of reference strength of the 5 wt % OCA specimens) showed that the cycles to failure of OCA-containing specimens was increased by two-fold compared with the OCA-free and capsule-free specimens. This study represents the first demonstration of dynamic, catalyst free self-healing in a biomaterial formulation. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 305–312, 2015.
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mechanical and cytotoxicity testing of acrylic Bone Cement embedded with microencapsulated 2 octyl cyanoacrylate
Journal of Biomedical Materials Research Part B, 2014Co-Authors: Alice B. W. Brochu, Gregory A Evans, William M. ReichertAbstract:The water-reactive tissue adhesive 2-octyl cyanoacrylate (OCA) was microencapsulated in polyurethane shells and incorporated into Palacos R Bone Cement. The tensile and compressive properties of the composite material were investigated in accordance with commercial standards, and fracture toughness of the capsule-embedded Bone Cement was measured using the tapered double-cantilever beam geometry. Viability and proliferation of MG63 human osteosarcoma cells after culture with extracts from Palacos R Bone Cement, capsule-embedded Palacos R Bone Cement, and OCA were also analyzed. Incorporating up to 5 wt % capsules had little effect on the compressive and tensile properties of the composite, but greater than 5 wt % capsules reduced these values below commercial standards. Fracture toughness was increased by 13% through the incorporation of 3 wt % capsules and eventually decreased below the toughness of the capsule-free controls at capsule contents of 15 wt % and higher. The effect on cell proliferation and viability in response to extracts prepared from capsule-embedded and commercial Bone Cements were not significantly different from each other, whereas extracts from OCA were moderately toxic to cells. Overall, the addition of lower wt % of OCA-containing microcapsules to commercial Bone Cement was found to moderately increase static mechanical properties without increasing the toxicity of the material.
Motoichi Kurisawa - One of the best experts on this subject based on the ideXlab platform.
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the development of a nanocrystalline apatite reinforced crosslinked hyaluronic acid tyramine composite as an injectable Bone Cement
Biomaterials, 2009Co-Authors: Motoichi Kurisawa, Joo Eun Chung, Jackie Y YingAbstract:We have developed an injectable Bone Cement composed of nanocrystalline apatite and crosslinked hyaluronic acid–tyramine conjugates (HA–Tyr). This Bone Cement was formed via the oxidative coupling of tyramine moieties catalyzed by hydrogen peroxide (H2O2) and horseradish peroxidise (HRP). The Bone Cement set within 60 s after H2O2 and HRP were added to the apatite/HA–Tyr pastes. The mechanical strength of the apatite/HA–Tyr Cement was tuned by varying the apatite loading and H2O2 concentration. This rapid enzyme-mediated setting of our Bone Cement results in minimal heat release (DH ¼� 11.39 J/g) as compared to conventional Bone Cements. The crystalline phase and crystallite size (20 nm) of the apatitic phase in our Bone Cement matched that of trabecular Bone. The storage modulus (G 0 ), yield stress (sy), and compressive stiffness (Ec) of our Bone Cement prepared with different apatite loadings and H2O2 concentrations were measured, and optimized at G
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the development of a nanocrystalline apatite reinforced crosslinked hyaluronic acid tyramine composite as an injectable Bone Cement
Biomaterials, 2009Co-Authors: Shona Y Pek, Motoichi Kurisawa, Joo Eun Chung, Shujun Gao, Jackie Y YingAbstract:We have developed an injectable Bone Cement composed of nanocrystalline apatite and crosslinked hyaluronic acid-tyramine conjugates (HA-Tyr). This Bone Cement was formed via the oxidative coupling of tyramine moieties catalyzed by hydrogen peroxide (H(2)O(2)) and horseradish peroxidase (HRP). The Bone Cement set within 60s after H(2)O(2) and HRP were added to the apatite/HA-Tyr pastes. The mechanical strength of the apatite/HA-Tyr Cement was tuned by varying the apatite loading and H(2)O(2) concentration. This rapid enzyme-mediated setting of our Bone Cement results in minimal heat release (DeltaH=-11.39 J/g) as compared to conventional Bone Cements. The crystalline phase and crystallite size (20 nm) of the apatitic phase in our Bone Cement matched that of trabecular Bone. The storage modulus (G'), yield stress (sigma(y)), and compressive stiffness (E(c)) of our Bone Cement prepared with different apatite loadings and H(2)O(2) concentrations were measured, and optimized at G'=40 MPa, sigma(y)=0.308 MPa and E(c)=2.270 MPa when the Cement was formed with 0.4 g/ml of apatite, 0.61 units/ml of HRP and 6.8 mm of H(2)O(2). Our biocompatible Bone Cement also successfully healed small Bone and joint defects in mice within 8 weeks.
Henk J Busscher - One of the best experts on this subject based on the ideXlab platform.
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pseudomonas aeruginosa biofilm formation and slime excretion on antibiotic loaded Bone Cement
Acta Orthopaedica, 2005Co-Authors: Danielle Neut, Johannes G E Hendriks, Jim R Van Horn, Henny C Van Der Mei, Henk J BusscherAbstract:Background Infection is an infrequent but serious complication of prosthetic joint surgery. These infections will usually not clear until the implant is removed and re-implantation has a high failure rate, especially when Pseudomonas aeruginosa is involved. Material and methods We examined Pseudomonas aeruginosa biofilm formation on plain and gentamicin-loaded Bone Cement with confocal scanning laser microscopy (CSLM). Two different stains were applied in order to visualize and quantify the distribution of bacterial cells and extracellular polymeric substances (slime) from the Bone Cement surface to the top of the biofilm. Staining with LIVE/DEAD viability stain differentiated between live and dead bacteria within the biofilm, and slime production was evaluated after staining with Calcofluor white. Results CSLM showed that the biofilm was a nonuniform structure of variable thickness, with differences in local bacterial cell and slime densities. Incorporation of gentamicin in Bone Cement resulted in a 44% reduction in bacterial viability, while the slime density increased significantly. In addition, conventional plate counting showed the development of small-colony variants on gentamicin-loaded Bone Cement with a decreased sensitivity for gentamicin (MIC: 8 mg/L), as compared with normal-sized colonies taken from plain and gentamicin-loaded Bone Cement (MIC: 3 mg/L). The enhanced slime production on antibiotic-loaded Bone Cement, together with the formation of small-colony variants, resulted in decreased susceptibility to antibiotics-probably concomitant with the onset of persistent and relapsing infections. Interpretation In the clinical situation, our findings help to explain the frequent re-implantation failure of joint replaCements infected with P. aeruginosa when the procedure has been performed using antibiotic-loaded Bone Cement.
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backgrounds of antibiotic loaded Bone Cement and prosthesis related infection
Biomaterials, 2004Co-Authors: Johannes G E Hendriks, J R Van Horn, H C Van Der Mei, Henk J BusscherAbstract:Antibiotic-loaded Bone Cement has been in use for over 30 years for the fixation of total joint arthroplasties, although its mechanism of action is still poorly understood. This review presents the backgrounds of Bone Cements, prosthesis-related infection and antibiotic-loaded Bone Cements. It is shown that antibiotic-loaded Bone Cement has a significant effect on bacteria, particularly in animal and clinical studies. However, recently, antimicrobial resistance among bacteria has been ascribed to the antibiotic-loaded Bone Cement. The unresolved issues both regarding the action of antibiotic-loaded Bone Cement and the nature of the antimicrobial resistance necessitate further research into the interaction of antibiotic-loaded Bone Cement and bacteria.