The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Aldo R Boccaccini - One of the best experts on this subject based on the ideXlab platform.
-
Solution Precursor Plasma Spraying (SPPS): A novel and simple process to obtain Bioactive Glass coatings
Materials Letters, 2018Co-Authors: Eugeni Cañas, Aldo R Boccaccini, M.j. Orts, Enrique SánchezAbstract:Abstract This research addresses the use of an emerging plasma spray technique known as Solution Precursor Plasma Spraying (SPPS) to obtain Bioactive Glass coatings. In SPPS, the feedstock is a sol precursor of the Bioactive Glass instead of Glass particles. Precursor feedstock composition (presence or not of acid catalyst), plasma torch enthalpy and stand-off distance of the spraying process have been varied to produce Bioactive Glass coatings of nominally 45S5 composition. A good quality coating was obtained when catalyst (0.2 M acid nitric) was used in the precursor and the plasma spraying took place with shorter stand-off distance and higher plasma enthalpy. Bioactivity in Simulated Body Fluid test was confirmed and an effect of the coating interconnected porosity to enhance bioactivity was observed.
-
electrophoretic deposition and characterization of chitosan Bioactive Glass composite coatings on mg alloy substrates
Electrochimica Acta, 2017Co-Authors: Svenja Heise, Michael Höhlinger, Victoria Wagener, Sannakaisa Virtanen, Yadir Torres Hernández, Juan José Pavón Palacio, Jose Antonio Rodriquez Ortiz, Aldo R BoccacciniAbstract:Abstract Electrophoretic deposition of chitosan-Bioactive Glass (45S5 composition) composite coatings on magnesium alloy (WE43) substrates was investigated. Two types of substrates were considered, one was the bare, non-pre-treated substrate, while the other one had been treated in Dulbecco’s Modified Eagle Medium (DMEM). The protective effect of the coatings (of ∼2 μm in thickness) against corrosion was tested using electrochemical impedance spectroscopy and the coatings’ Bioactive behaviour was determined in simulated body fluid. A tribo-mechanical characterization of the coatings was performed. Overall, results confirmed the importance of pre-treating the substrate to corrosion protective chitosan-Bioactive Glass coatings on WE43 alloy.
-
designing porous bone tissue engineering scaffolds with enhanced mechanical properties from composite hydrogels composed of modified alginate gelatin and Bioactive Glass
ACS Biomaterials Science & Engineering, 2016Co-Authors: Bapi Sarker, Kai Zheng, Rainer Detsch, Aldo R BoccacciniAbstract:The combination of biodegradable polymers and Bioactive inorganic materials is being widely used for designing bone tissue engineering scaffolds. Here we report a composite hydrogel system composed of Bioactive Glass incorporated in covalently cross-linked oxidized alginate-gelatin hydrogel (ADA-GEL) for designing porous scaffolds with tunable stiffness and degradability using freeze-drying technique. Because of the presence of Bioactive Glass, the cross-linking kinetic and cross-linking degree of the hydrogels are significantly increased, which is the main factor for the measured enhanced mechanical strength of the Bioactive Glass containing ADA-GEL scaffolds. The hydrogels with high cross-linking degree exhibit low protein release profile and low degradability. Apatite formation on Bioactive Glass containing hydrogel-based scaffolds is confirmed by FTIR. Bone marrow-derived stromal cell growth is promoted in pristine ADA-GEL and 1% Bioactive Glass containing ADA-GEL scaffolds compared to the scaffolds o...
-
physicochemical biological and drug release properties of gallium crosslinked alginate nanoparticulate Bioactive Glass composite films
Soft Matter, 2011Co-Authors: Aldo R Boccaccini, Viviana Mourino, P Newby, F Pishbin, Juan Pablo Cattalini, Silvia LucangioliAbstract:The aim of this work was to develop biodegradable and Bioactive materials with sufficient structural integrity and prophylaxis effect against infection based on alginate-Bioactive Glass composite. The incorporation of Bioactive Glass nanoparticles (NBG) into Ga-crosslinked alginate films significantly improved their mechanical properties when compared with films fabricated with micron-sized Bioactive Glass particles. In addition, Ga-alginate films containing NBG induced a bacteriostatic effect in vitro towards S. aureus due to the presence of Ga ions (Ga3+), whose release is controlled solely by crosslinking the ion with alginate. Biomineralization studies in simulated body fluid suggested the deposition of hydroxyapatite on the surface of the films indicating their Bioactive nature. In addition, the films were shown to feature biocompatibility toward osteoblast-like cells. Thus, it was shown that Ga-crosslinked composite films possessed relevant physicochemical, biological and controlled bacteriostatic effects which make these materials promising candidates for bone tissue engineering applications.
-
polymer Bioactive Glass nanocomposites for biomedical applications a review
Composites Science and Technology, 2010Co-Authors: Dirk Mohn, Wendelin J. Stark, Aldo R Boccaccini, Zhongkui Hong, Melek Erol, Joao F ManoAbstract:Abstract Nanoscale Bioactive Glasses have been gaining attention due to their reported superior osteoconductivity when compared to conventional (micron-sized) Bioactive Glass materials. The combination of Bioactive Glass nanoparticles or nanofibers with polymeric systems enables the production of nanocomposites with potential to be used in a series of orthopedic applications, including scaffolds for tissue engineering and regenerative medicine. This review presents the state of art of the preparation of nanoscale Bioactive Glasses and corresponding composites with biocompatible polymers. The recent developments in the preparation methods of nano-sized Bioactive Glasses are reviewed, covering sol–gel routes, microemulsion techniques, gas phase synthesis method (flame spray synthesis), laser spinning, and electro-spinning. Then, examples of the preparation and properties of nanocomposites based on such inorganic bionanomaterials are presented, obtained using various polymer matrices, including polyesters such as poly(hydroxybutyrate), poly(lactic acid) and poly(caprolactone), and natural-based polymers such as polysaccharides (starch, chitin, chitosan) or proteins (silk fibroin, collagen). The physico-chemical, mechanical, and biological advantages of incorporating nanoscale Bioactive Glasses in such biodegradable nanocomposites are discussed and the possibilities to expand the use of these materials in other nanotechnology concepts aimed to be used in different biomedical applications are also highlighted.
Mohamed N Rahaman - One of the best experts on this subject based on the ideXlab platform.
-
antibiotic elution and mechanical strength of pmma bone cement loaded with borate Bioactive Glass
Journal of Bone and Joint Infection, 2018Co-Authors: Grahmm A Funk, Mohamed N Rahaman, Jonathan C Burkes, Kimberly A Cole, Terence E MciffAbstract:Introduction: Local delivery of antibiotics using bone cement as the delivery vehicle is an established method of managing implant-associated orthopedic infections. Various fillers have been added to cement to increase antibiotic elution, but they often do so at the expense of strength. This study evaluated the effect of adding a borate Bioactive Glass, previously shown to promote bone formation, on vancomycin elution from PMMA bone cement. Methods: Five cement composites were made: three loaded with borate Bioactive Glass along with 0, 1, and 5 grams of vancomycin and two without any Glass but with 1 and 5 grams vancomycin to serve as controls. The specimens were soaked in PBS. Eluate of vancomycin was collected every 24 hours and analyzed by HPLC. Orthopedic-relevant mechanical properties of each composite were tested over time. Results: The addition of borate Bioactive Glass provided an increase in vancomycin release at Day 1 and an increase in sustained vancomycin release throughout the treatment period. An 87.6% and 21.1% increase in cumulative vancomycin release was seen for both 1g and 5g loading groups, respectively. Compressive strength of all composites remained above the weight-bearing threshold of 70 MPa throughout the duration of the study with the Glass-containing composites showing comparable strength to their respective controls. Conclusion: The incorporation of borate Bioactive Glass into commercial PMMA bone cement can significantly increase the elution of vancomycin. The mechanical strength of the cement-Glass composites remained above 70 MPa even after soaking for 8 weeks, suggesting their suitability for orthopedic weight-bearing applications.
-
Bioactive Glass innovations through academia industry collaboration
International Journal of Applied Glass Science, 2016Co-Authors: Qiang Fu, John C Mauro, Mohamed N RahamanAbstract:Since the discovery of 45S5 Bioactive Glass by Hench in 1969, numerous studies have been conducted on the use of Bioactive Glasses for the repair of hard and soft tissues. However, limited progress has been achieved in the commercialization of Bioactive Glass as medical products, with the most successful ones being 45S5-based Perioglas®, Novabone®, and NovaMin®. This indicates that a gap exists between academic research and industrial scale-up. Our work attempts to provide a preliminary study on the two well-known Bioactive Glasses, 45S5 and 13-93, to evaluate their suitability for mass production in an industrial platform. Glass properties including strain, annealing, and softening points, thermal expansion, density, and liquidus temperature are characterized. Our results show that both Glasses have a substantially lower liquidus viscosity than soda lime silicate (SLS) Glass, suggesting that melting and forming them in an industrial continuous-unit melting system could be challenging. Innovations in Bioactive Glass compositions by delving into literature, referencing relevant phase diagrams, conducting design of experiments (DOE), and utilizing modeling tools are needed. Furthermore, joint research between academia and industry on the development of new forming techniques is critical to meet the increasing demand for Bioactive Glass in a variety of sizes and shapes.
-
evaluation of three dimensional silver doped borate Bioactive Glass scaffolds for bone repair biodegradability biocompatibility and antibacterial activity
Journal of Materials Research, 2015Co-Authors: Hui Wang, Mohamed N Rahaman, Wenhai Huang, Shichang Zhao, Song Ye, Changqing Zhang, Deping WangAbstract:The development of synthetic scaffolds with a desirable combination of properties, such as bioactivity, the ability to locally deliver antibacterial agents and high osteogenic capacity, is a challenging but promising approach in bone tissue engineering. In this study, scaffolds of a borosilicate Bioactive Glass (composition: 6Na 2 O, 8K 2 O, 8MgO, 22CaO, 36B 2 O 3 , 18SiO 2 , 2P 2 O 5 ; mol%) with controllable antibacterial activity were developed by doping the parent Glass with varying amounts of Ag 2 O (0.05, 0.5, and 1.0 wt%). The addition of the Ag 2 O lowered the compressive strength and degradation of the Bioactive Glass scaffolds but it did not affect the formation of hydroxyapatite on the surface of the Glass as determined by energy dispersive x-ray analysis, x-ray diffraction, and Fourier transform infrared analysis. The Ag 2 O-doped scaffolds showed a sustained release of Ag ions over more than 8 weeks in simulated body fluid and resistance against colonization by the bacterial strains Escherichia coli and Staphylococcus aureus . In vitro cell culture showed better adhesion, proliferation, and alkaline phosphatase activity of murine osteoblastic MC3T3-E1 cells on the Ag 2 O-doped Bioactive Glass scaffolds than on the undoped scaffolds. The results indicate that these Ag-doped borosilicate Bioactive Glass scaffolds may have potential in repairing bone coupled with providing a lower risk of bacterial infection.
-
in vitro bioactivity cytocompatibility and antibiotic release profile of gentamicin sulfate loaded borate Bioactive Glass chitosan composites
Journal of Materials Science: Materials in Medicine, 2013Co-Authors: Xu Cui, Hui Wang, Zhongping Xie, Shihua Luo, Nai Zhou, Wenhai Huang, Mohamed N RahamanAbstract:Borate Bioactive Glass-based composites have been attracting interest recently as an osteoconductive carrier material for local antibiotic delivery. In the present study, composites composed of borate Bioactive Glass particles bonded with a chitosan matrix were prepared and evaluated in vitro as a carrier for gentamicin sulfate. The bioactivity, degradation, drug release profile, and compressive strength of the composite carrier system were studied as a function of immersion time in phosphate-buffered saline at 37 °C. The cytocompatibility of the gentamicin sulfate-loaded composite carrier was evaluated using assays of cell proliferation and alkaline phosphatase activity of osteogenic MC3T3-E1 cells. Sustained release of gentamicin sulfate occurred over ~28 days in PBS, while the Bioactive Glass converted continuously to hydroxyapatite. The compressive strength of the composite loaded with gentamicin sulfate decreased from the as-fabricated value of 24 ± 3 MPa to ~8 MPa after immersion for 14 days in PBS. Extracts of the soluble ionic products of the borate Glass/chitosan composites enhanced the proliferation and alkaline phosphatase activity of MC3T3-E1 cells. These results indicate that the gentamicin sulfate-loaded composite composed of chitosan-bonded borate Bioactive Glass particles could be useful clinically as an osteoconductive carrier material for treating bone infection.
-
Bioactive Glass scaffolds for bone tissue engineering state of the art and future perspectives
Materials Science and Engineering: C, 2011Co-Authors: Qiang Fu, Mohamed N Rahaman, Eduardo Saiz, Antoni P TomsiaAbstract:The repair and regeneration of large bone defects resulting from disease or trauma remains a significant clinical challenge. Bioactive Glass has appealing characteristics as a scaffold material for bone tissue engineering, but the application of Glass scaffolds for the repair of load-bearing bone defects is often limited by their low mechanical strength and fracture toughness. This paper provides an overview of recent developments in the fabrication and mechanical properties of Bioactive Glass scaffolds. The review reveals the fact that mechanical strength is not a real limiting factor in the use of Bioactive Glass scaffolds for bone repair, an observation not often recognized by most researchers and clinicians. Scaffolds with compressive strengths comparable to those of trabecular and cortical bones have been produced by a variety of methods. The current limitations of Bioactive Glass scaffolds include their low fracture toughness (low resistance to fracture) and limited mechanical reliability, which have so far received little attention. Future research directions should include the development of strong and tough Bioactive Glass scaffolds, and their evaluation in unloaded and load-bearing bone defects in animal models.
Larry L. Hench - One of the best experts on this subject based on the ideXlab platform.
-
Chronology of Bioactive Glass Development and Clinical Applications
New Journal of Glass and Ceramics, 2020Co-Authors: Larry L. HenchAbstract:The key research and development steps for Bioactive Glass (45S5 BioGlass) are documented from the date of discovery in 1969 through FDA approvals of the first dental, ENT, maxillo-facial and orthopedic clinical products. Understanding the mechanisms and quantifying the rapid surface reactions to form a bone-bonding hydroxyl-carbonate apatite (HCA) layer on the Bioactive Glass in contact with living bone was a vital part of the early development of this class of biomaterials. A key later discovery was enhanced osteogenesis and in situ bone regeneration by controlled release of ionic dissolution products from the Bioactive Glass particulates that leads to up-regulation and activation of seven families of genes, a process called osteostimulation.
-
controlling ion release from Bioactive Glass foam scaffolds with antibacterial properties
Journal of Materials Science: Materials in Medicine, 2006Co-Authors: Julian R. Jones, Lisa M Ehrenfried, Priya Saravanapavan, Larry L. HenchAbstract:Bioactive Glass scaffolds have been produced, which meet many of the criteria for an ideal scaffold for bone tissue engineering applications, by foaming sol-gel derived Bioactive Glasses. The scaffolds have a hierarchical pore structure that is very similar to that of cancellous bone. The degradation products of Bioactive Glasses have been found to stimulate the genes in osteoblasts. This effect has been found to be dose dependent. The addition of silver ions to Bioactive Glasses has also been investigated to produce Glasses with bactericidal properties. This paper discusses how changes in the hierarchical pore structure affect the dissolution of the Glass and therefore its bioactivity and rate of ion delivery and demonstrates that silver containing Bioactive Glass foam scaffolds can be synthesised. It was found that the rate of release of Si and Ca ions was more rapid for pore structures with a larger modal pore diameter, although the effect of tailoring the textural porosity on the rate of ion release was more pronounced. Bioactive Glass scaffolds, containing 2 mol% silver, released silver ions at a rate that was similar to that which has previously been found to be bactericidal but not high enough to be cytotoxic to bone cells.
-
Analysis of pore interconnectivity in Bioactive Glass foams using X-ray microtomography
Scripta Materialia, 2004Co-Authors: Robert C. Atwood, Julian R. Jones, Larry L. HenchAbstract:Abstract X-ray microtomography and three-dimensional image analysis were used to characterise both the pore size and interpore aperture size distributions in Bioactive Glass foam tissue engineering scaffolds. These techniques allow quantification of the scaffold’s key macrostructural features that control tissue growth. The technique was applied to determine the optimum sintering temperature.
-
crystallization kinetics of tape cast Bioactive Glass 45s5
Journal of Non-crystalline Solids, 2003Co-Authors: D C Clupper, Larry L. HenchAbstract:The crystallization kinetics of tape cast Bioactive Glass 45S5 was studied using non-isothermal methods. XRD confirmed that Na2Ca2Si3O9 was formed during heating up to 1000 °C. The modified Kissinger equation was used to determine that the activation energy for crystallization was 350 kJ/mol. The Avrami exponent, n, was determined to be 0.96 (Ozawa method) and 0.94 (Augis–Bennett method). Such results indicated that the particulate jet milled Bioactive Glass 45S5 (3 μm average particle size) undergoes surface crystallization during heat treatment. Previous results showed that the porosity of tape cast sintered Bioactive Glass 45S5 strongly influenced the in vitro bioactivity. Ease of crystallization of tape cast Bioactive Glass 45S5 suggested that it is fully crystalline prior to undergoing significant densification above 800 °C.
-
broad spectrum bactericidal activity of ag 2 o doped Bioactive Glass
Antimicrobial Agents and Chemotherapy, 2002Co-Authors: Maria Bellantone, Huw D Williams, Larry L. HenchAbstract:Bioactive Glass has found extensive application as an orthopedic and dental graft material and most recently also as a tissue engineering scaffold. Here we report an initial investigation of the in vitro antibacterial properties of AgBG, a novel Bioactive Glass composition doped with Ag 2 O. The bacteriostatic and bactericidal properties of this new material and of two other Bioactive Glass compositions, 45S5 BioGlass and BG, have been studied by using Escherichia coli , Pseudomonas aeruginosa , and Staphylococcus aureus as test microorganisms. Concentrations of AgBG in the range of 0.05 to 0.20 mg of AgBG per ml of culture medium were found to inhibit the growth of these bacteria. Not only was AgBG bacteriostatic, but it also elicited a rapid bactericidal action. A complete bactericidal effect was elicited within the first hours of incubation at AgBG concentrations of 10 mg ml −1 . 45S5 BioGlass and BG had no effect on bacterial growth or viability. The antibacterial action of AgBG is attributed exclusively to the leaching of Ag + ions from the Glass matrix. Analytical measurements rule out any contribution to AgBG-mediated bacterial killing by changes in pH or ionic strength or the dissolution of other ionic species from the biomaterials. Our observations of the dissolution profiles of Ag + from AgBG in the presence and absence of bacteria are consistent with silver accumulation by the bacteria.
Mohammed Elbadawi - One of the best experts on this subject based on the ideXlab platform.
-
porous hydroxyapatite Bioactive Glass hybrid scaffolds fabricated via ceramic honeycomb extrusion
Journal of the American Ceramic Society, 2018Co-Authors: Mohammed Elbadawi, Zena Wally, Ian M ReaneyAbstract:The successful fabrication of hydroxyapatite-Bioactive Glass scaffolds using honeycomb extrusion is presented herein. Hydroxyapatite was combined with either 10 wt% stoichiometric BioGlass® (BG1), ...
-
porous hydroxyapatite Bioactive Glass hybrid scaffolds fabricated via ceramic honeycomb extrusion
Journal of the American Ceramic Society, 2018Co-Authors: Mohammed Elbadawi, Zena Wally, Ian M ReaneyAbstract:The successful fabrication of hydroxyapatite‐Bioactive Glass scaffolds using honeycomb extrusion is presented herein. Hydroxyapatite was combined with either 10 wt% stoichiometric BioGlass® (BG1), calcium‐excess BioGlass® (BG2) or canasite (CAN). For all composite materials, Glass‐induced partial phase transformation of the HA into the mechanically weaker β‐tricalcium phosphate (TCP) occurred but XRD data demonstrated that BG2 exhibited a lower volume fraction of TCP than BG1. Consequently, the maximum compressive strength observed for BG1 and BG2 were 30.3 ± 3.9 and 56.7 ± 6.9 MPa, respectively, for specimens sintered at 1300°C. CAN scaffolds, in contrast, collapsed when handled when sintered below 1300°C, and thus failed. The microstructure illustrated a morphology similar to that of BG1 sintered at 1200°C, and hence a comparable compressive strength (11.4 ± 3.1 MPa). The results highlight the great potential offered by honeycomb extrusion for fabricating high‐strength porous scaffolds. The compressive strengths exceed that of commercial scaffolds, and biological tests revealed an increase in cell viability over 7 days for all hybrid scaffolds. Thus it is expected that the incorporation of 10 wt% Bioactive Glass will provide the added advantage of enhanced bioactivity in concert with improved mechanical stability.
Ian M Reaney - One of the best experts on this subject based on the ideXlab platform.
-
porous hydroxyapatite Bioactive Glass hybrid scaffolds fabricated via ceramic honeycomb extrusion
Journal of the American Ceramic Society, 2018Co-Authors: Mohammed Elbadawi, Zena Wally, Ian M ReaneyAbstract:The successful fabrication of hydroxyapatite-Bioactive Glass scaffolds using honeycomb extrusion is presented herein. Hydroxyapatite was combined with either 10 wt% stoichiometric BioGlass® (BG1), ...
-
porous hydroxyapatite Bioactive Glass hybrid scaffolds fabricated via ceramic honeycomb extrusion
Journal of the American Ceramic Society, 2018Co-Authors: Mohammed Elbadawi, Zena Wally, Ian M ReaneyAbstract:The successful fabrication of hydroxyapatite‐Bioactive Glass scaffolds using honeycomb extrusion is presented herein. Hydroxyapatite was combined with either 10 wt% stoichiometric BioGlass® (BG1), calcium‐excess BioGlass® (BG2) or canasite (CAN). For all composite materials, Glass‐induced partial phase transformation of the HA into the mechanically weaker β‐tricalcium phosphate (TCP) occurred but XRD data demonstrated that BG2 exhibited a lower volume fraction of TCP than BG1. Consequently, the maximum compressive strength observed for BG1 and BG2 were 30.3 ± 3.9 and 56.7 ± 6.9 MPa, respectively, for specimens sintered at 1300°C. CAN scaffolds, in contrast, collapsed when handled when sintered below 1300°C, and thus failed. The microstructure illustrated a morphology similar to that of BG1 sintered at 1200°C, and hence a comparable compressive strength (11.4 ± 3.1 MPa). The results highlight the great potential offered by honeycomb extrusion for fabricating high‐strength porous scaffolds. The compressive strengths exceed that of commercial scaffolds, and biological tests revealed an increase in cell viability over 7 days for all hybrid scaffolds. Thus it is expected that the incorporation of 10 wt% Bioactive Glass will provide the added advantage of enhanced bioactivity in concert with improved mechanical stability.