Browsing by Author "Deliormanli A.M."
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Item Direct-write assembly of silicate and borate bioactive glass scaffolds for bone repair(2012) Deliormanli A.M.; Rahaman M.N.Silicate (13-93) and borate (13-93B3) bioactive glass scaffolds were created by robotic deposition (robocasting) of organic solvent-based suspensions and evaluated in vitro for potential application in bone repair. Suspensions (inks) were developed, characterized, and deposited layer-by-layer to form three-dimensional scaffolds with a grid-like microstructure (porosity ≈50%; pore width 420 ± 30 μm). The mechanical response of the scaffolds was tested in compression, and the conversion of the glass to hydroxyapatite (HA)-like material in a simulated body fluid (SBF) was evaluated. As fabricated, the 13-93 scaffolds had a compressive strength 142 ± 20. MPa, comparable to the strength of human cortical bone, while the strength of the 13-93B3 scaffolds (65 ± 11. MPa), was far higher than that for trabecular bone. When immersed in SBF, the borate 13-93B3 scaffolds converted faster than the silicate 13-93 scaffolds to an HA-like material, but they also showed a sharper decrease in strength with immersion time. Based on their high compressive strength and bioactivity, the scaffolds fabricated in this work by robocasting could have potential application in the repair of load-bearing bone. © 2012 Elsevier Ltd.Item Size-dependent degradation and bioactivity of borate bioactive glass(2013) Deliormanli A.M.Borate bioactive glass has been shown to convert faster and more completely to hydroxyapatite and enhances new bone formation in vivo when compared to silicate bioactive glass. In this work, bioactive borate glass scaffolds, with a grid-like microstructure having different filament diameters (130±10 μm to 300±20 μm), were prepared by a robotic deposition technique. In vitro degradation and hydroxyapatite formation on borate bioactive glass scaffolds were investigated in a simulated body fluid (SBF) at 37° C under static conditions. Mineralization of borate and silicate bioactive glass powders was also tested under the same conditions. When immersed in SBF, degradation rate of the scaffolds and conversion to a hydroxyapatite-like material showed dependence on filament diameter. Similarly, conversion of bioactive glass particles to calcium phosphate phase strongly depends on the particle size and the sample/SBF ratio of the system. Large particles and scaffolds composed of thick struts formed less apatite and degraded less completely compared with smaller particles and thinner struts. Results showed that it is possible to tailor the degradation rate and bioactivity by changing the filament diameter of the borate bioactive glass scaffolds produced by robocasting. © 2013 Elsevier Ltd and Techna Group S.r.l.Item In vitro assessment of degradation and mineralisation of V2O5substituted borate bioactive glass scaffolds(Maney Publishing, 2014) Deliormanli A.M.Bioactive glasses are promising scaffold materials for bone regeneration because of their unique ability to convert to hydroxyapatite (HA) in vivo, and their ability to bond with bone and soft tissues. In this study, borate based (13-93B3) bioactive glass powders containing up to 3 wt- %V2O5were prepared by the melt quench technique. Vanadium was chosen because of its therapeutic action. It is known to promote initial wound healing and this may be especially beneficial to applications involving diabetic patients and soft tissue healing. Bioactive glass scaffolds were fabricated using the polymer foam replication method. In vitro degradation and bioactivity of the scaffolds were evaluated in simulated body fluid under static conditions. Results revealed that the vanadium-containing borate glasses have higher degradation rates compared to the bare borate glass 13-93B3. Due to low chemical durability, substituted glasses exhibited a good in vitro bioactive response. Taking into account the high in vitro HA forming ability, borate glass scaffolds containing V+5therapeutic ions are promising candidates for bone tissue engineering applications. © 2014 W. S. Maney & Son Ltd.Item Evaluation of borate bioactive glass scaffolds with different pore sizes in a rat subcutaneous implantation model(2014) Deliormanli A.M.; Liu X.; Rahaman M.N.Borate bioactive glass has been shown to convert faster and more completely to hydroxyapatite and enhance new bone formation in vivo when compared to silicate bioactive glass (such as 45S5 and 13-93 bioactive glass). In this work, the effects of the borate glass microstructure on its conversion to hydroxyapatite (HA) in vitro and its ability to support tissue ingrowth in a rat subcutaneous implantation model were investigated. Bioactive borate glass scaffolds, designated 13-93B3, with a grid-like microstructure and pore widths of 300, 600, and 900 μm were prepared by a robocasting technique. The scaffolds were implanted subcutaneously for 4 weeks in Sprague Dawley rats. Silicate 13-93 glass scaffolds with the same microstructure were used as the control. The conversion of the scaffolds to HA was studied as a function of immersion time in a simulated body fluid. Histology and scanning electron microscopy were used to evaluate conversion of the bioactive glass implants to hydroxyapatite, as well as tissue ingrowth and blood vessel formation in the implants. The pore size of the scaffolds was found to have little effect on tissue infiltration and angiogenesis after the 4-week implantation. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.Item Preparation, in vitro mineralization and osteoblast cell response of electrospun 13-93 bioactive glass nanofibers(Elsevier Ltd, 2015) Deliormanli A.M.In this study, silicate based 13-93 bioactive glass fibers were prepared through sol-gel processing and electrospinning technique. A precursor solution containing poly (vinyl alcohol) and bioactive glass sol was used to produce fibers. The mixture was electrospun at a voltage of 20 kV by maintaining tip to a collector distance of 10 cm. The amorphous glass fibers with an average diameter of 464 ± 95 nm were successfully obtained after calcination at 625 °C. Hydroxyapatite formation on calcined 13-93 fibers was investigated in simulated body fluid (SBF) using two different fiber concentrations (0.5 and 1 mg/ml) at 37 °C. When immersed in SBF, conversion to a calcium phosphate material showed a strong dependence on the fiber concentration. At 1 mg/ml, the surface of the fibers converted to the hydroxyapatite-like material in SBF only after 30 days. At lower solid concentrations (0.5 mg/ml), an amorphous calcium phosphate layer formation was observed followed by the conversion to hydroxyapatite phase after 7 days of immersion. The XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay was conducted to evaluate the osteoblast cell response to the bioactive glass fibers. © 2015 Elsevier B.V. All rights reserved.Item Preparation and in vitro characterization of electrospun 45S5 bioactive glass nanofibers(Elsevier Ltd, 2015) Deliormanli A.M.Bioactive glasses are widely used in biomedical applications due to their ability to bond to bone and even to soft tissues. In this study, 45S5 bioactive glass fibers were prepared through sol-gel processing and electrospinning technique. A precursor solution containing poly vinyl alcohol and bioactive glass sol was used to produce fibers. The mixture was electrospun at a voltage of 20 kV by maintaining tip to a collector distance of 8 cm. The fibers with an average diameter of 337781 nm (before calcination) were successfully obtained. Results showed that the crystalline phase of the fibers was largely influenced by the calcination temperature. Hydroxyapatite formation on calcined 45S5 fibers was investigated in simulated body fluid (SBF) using different fiber/SBF (F/S) ratios (0.5, 1, 2 and 10 mg/ml) at 37 °C. When immersed in SBF, conversion to a calcium phosphate material showed a strong dependence on the F/S ratio. At high solid concentration (10 mg/ml), surface of the fibers could not be converted to the HA-like material in SBF after 30 days. At lower solid concentrations (2, 1 and 0.5 mg/ml) an amorphous calcium phosphate layer formation was observed followed by the conversion to hydroxyapatite. © 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Item Fabrication and characterization of poly(ε-caprolactone) coated silicate and borate-based bioactive glass composite scaffolds(SAGE Publications Ltd, 2016) Deliormanli A.M.In this study, silicate 13-93 and borate based 13-93B3 bioactive glass scaffolds with high porosity and interconnected pore structure (pore size 100-500 μm) were prepared by foam replication method. In order to improve the mechanical properties, the scaffolds were coated and infiltrated with a poly(ε-caprolactone) (PCL) solution at different concentrations (5, 10, and 20 wt%). Results revealed that the mechanical properties of the scaffolds were significantly improved by the PCL coating. The addition of 10% PCL coating led to approximately 10-fold increase of compressive strength in comparison with noncoated scaffolds. The bioactivity of scaffolds upon immersion in simulated body fluid was maintained in the PCL-coated scaffolds at all concentrations; however, a decrease in the formation rate and amount of crystalline hydroxyapatite was observed as the PCL concentration was increased in the coating layer. Degradation rate of the borate-based bioactive glass scaffolds was tailored by the PCL coating. It is concluded that the fabricated bioactive composite scaffolds represent promising candidates for bone tissue engineering applications. © SAGE Publications.Item Graphene-containing PCL- coated Porous 13-93B3 Bioactive Glass Scaffolds for Bone Regeneration(Institute of Physics Publishing, 2018) Türk M.; Deliormanli A.M.Borate-based 13-93B3 bioactive glass scaffolds were coated with the graphene-containing poly-caprolactone (PCL) solution to prepare electrically conductive composites for biomedical applications. Results revealed that electrical conductivity of the scaffolds increased with increasing concentration of graphene nanoparticles. Significant difference was not observed in hydroxyapatite forming ability of the bare and the graphene-containing scaffolds immersed in simulated body fluid. In vitro cytotoxicity experiments (XTT tests) showed that pre-osteoblastic MC3T3-E1 cell viability percentages of the graphene- containing samples was higher than control group samples after 7 days of incubation. However, a decrease in cell viability rates was obtained after 14 days of incubation for samples coated with PCL containing graphene starting from 3 wt%. Additionally, results obtained in the live-dead assay were consistent with the results of XTT tests. A higher ALP activity was detected in cells cultured on the graphene-containing borate glass scaffolds than those on the bare PCL coated 13-93B3 scaffolds suggesting the presence of graphene nanopowders stimulated an early stage of osteoblastic differentiation. SEM analysis showed that MC3T3-E1 cells exhibited a flat appearance and spread out through the surface in all groups of scaffolds starting from 3 days of incubation. © 2018 IOP Publishing Ltd.Item Erbium (III)- and Terbium (III)-containing silicate-based bioactive glass powders: physical, structural and nuclear radiation shielding characteristics(Springer Science and Business Media Deutschland GmbH, 2021) Deliormanli A.M.; Issa S.A.M.; Al-Buriahi M.S.; Rahman B.; Zakaly H.M.H.; Tekin H.O.Erbium (III)- and terbium (III)-containing (1, 3 and 5 wt%) silicate-based bioactive glass powders were synthesized using sol–gel method. Their structural and physical properties were investigated. Radiation attenuation properties of the prepared glass samples were examined using Monte Carlo simulations. The photon transmission properties of the prepared bioactive specimens were obtained via Phy-X PSD program and FLUKA simulation. Results showed that all of the glasses synthesized in the study were amorphous. The true density values were measured in the range of 2.57–2.68 g/cm3. Simulation studies revealed that the lowest neutron cross section was observed for the pure 13–93 bioactive glass sample and the maximum neutron cross section was noted for the prepared bioactive specimens of 5% Er and 5% Tb. Bioactive glass powders synthesized in the study have potential to be used as radiation shielding material in tissue engineering applications. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.Item Effect of polycaprolactone scaffolds containing different weights of graphene on healing in large osteochondral defect model(Taylor and Francis Ltd., 2022) Basal O.; Ozmen O.; Deliormanli A.M.Now it is possible to combine the different biomaterial properties of graphene and 3 D printing scaffolds produced by tissue engineering for cartilage repair. In the study graphene-containing (1, 3, 5, 10 wt%), porous and oriented poly-ε-caprolactone-based scaffolds were prepared by robocasting method to use in the regeneration of large osteochondral defects. The scaffolds were implanted into the full-thickness osteochondral defect in a rabbit model to evaluate the regeneration of the defect in vivo. For this purpose, twenty female New Zealand white rabbits were used and they were euthanized at 4 and 8 weeks of implantation. The reparative osteochondral tissues were harvested from rabbit distal femurs and then processed for gross appearance assessment, radiographic imaging, histopathological, histochemical and immunohistochemical examinations. Results revealed that graphene-containing graft materials caused significant amelioration at the defect areas. Graphene-containing graft materials improved the fibrous, chondroid and osseous tissue regeneration compared to the control group. The expressions of bone morphogenetic protein-2 (BMP-2), collagen-1 (col-1), vascular endothelial growth factor (VEGF) and alkaline phosphatase (ALP) expressions were more prominent in graphene-containing PCL implanted groups (p <.001). Picrosirrius red method was used for to evaluate connective and muscle tissues. Results also revealed that the ameliorative effect of graphene increased by the elevation in concentration. The most prominent healing was observed in 10 wt% graphene-containing PCL based composite scaffold implanted group. This study results showed that graphene-containing PCL scaffolds enhanced the healing significantly in large osteochondral defect areas compared to the control groups. © 2022 Informa UK Limited, trading as Taylor & Francis Group.Item Two-dimensional molybdenum disulfide/polymer-coated bioactive glass scaffolds for tissue engineering: Fabrication, structural, mechanical, bioactivity, and radiation interaction properties(Elsevier Ltd, 2023) Deliormanli A.M.; Ensoylu M.; ALMisned G.; Tekin H.O.Molybdenum disulfide (MoS2)-based nanostructures are widely used in environmental protection and biomedicine owing to their biological, physical, chemical, electrical, and mechanical properties. In this study, polycaprolactone (PCL)- and polylactide-co-glycolide (PLGA)-coated bioactive glass scaffolds containing MoS2 nanoparticles are prepared, and their usability in bone tissue engineering applications is evaluated. Borate bioactive glass scaffolds are fabricated using the replication method and coated with PCL or PLGA solutions (5 wt%) containing MoS2 (0.1, 0.2, 0.5, 1, and 2 wt%) nanoparticles. The structural and mechanical properties of the scaffolds and their bioactivity in simulated body fluids are investigated comprehensively. The ionization–radiation-shielding properties are investigated using Monte Carlo simulations. The results show that the polymer coating layer and presence of MoS2 nanoparticles in the polymer matrix improves the mechanical properties of the scaffolds. The addition of MoS2 nanoparticles to the structure increases the hydroxyapatite-forming ability of bioactive glass-based composites. Additionally, the prepared composite scaffolds exhibit high radiation-shielding ability owing to the presence of MoS2 nanoparticles embedded in the polymer matrix that shields the glass surface. Bioactive glass composite scaffolds containing MoS2 nanoparticles demonstrate promising potential for bone regeneration and radiation-shielding applications. © 2023 Elsevier Ltd and Techna Group S.r.l.Item Graphene-bioactive glass composites: Structural, Vickers hardness, and gamma-ray attenuation characteristics(Frontiers Media S.A., 2023) Deliormanli A.M.; ALMisned G.; Ene A.; Tekin H.O.Introduction: Graphene-based materials have gained increasing attention for use in radiation attenuation applications. In this study, pristine graphene nanoplatelet-containing (1, 3, 5, and 10 wt%) borate-based bioactive glass composites were prepared. Methods: Structural properties, Vickers microhardness, and gamma-ray radiation shielding properties of the fabricated composites were examined in detail. Results and Discussion: Results revealed that the inclusion of the graphene in the glass matrix led to a decrease in the bulk density of the glass-based composites from 2.41 to 2.31 g/cm3. Similarly, a decrease in Vickers hardness was obtained as the graphene concentration was increased due to a convoluted effect of the non-uniform distribution of graphene nanoplatelets in the bioactive glass matrix and the higher residual porosity. Vickers hardness of the bare and the 10 wt% graphene-containing bioactive glass discs were measured to be 5.03 ± 0.28 GPa and 1.87 ± 0.56 GPa, respectively. On the other hand, the incorporation of graphene starting from 3 wt% decreased the crack propagation after indentation which may be attributed to an increase in fracture toughness. In the study, fundamental gamma ray absorption properties of graphene-containing bioactive glasses were examined in the 0.015–15 MeV incident photon energy range. For this purpose, the Py-MLBUF code was employed to determine gamma ray absorption parameters. Results showed that linear attenuation coefficients of the glass-based composites decreased due to a decrease in the density of the samples. On the other hand, as graphene was incorporated into the bioactive glass structure, exposure buildup factor and energy absorption buildup factor values increased. The growing graphene ratio in the glass structure contributed negatively to the photon’s tendency to interact with the material. Copyright © 2023 Deliormanli, ALMisned, Ene and Tekin.