JOURNAL OF POROUS MATERIALS

Macro-channeled porous hydroxyapatite (HA) scaffolds were fabricated by a polymer foam replication method. Composites were prepared by coating the surface of HA scaffolds with polycaprolactone (PCL) in the presence of graphene nanopowders (in the form of flakes) and multi-walled carbon nanotubes (MWCNTs) at different concentrations. Compression strength of the scaffolds was investigated as a function of additive concentration. Results revealed that the use of PCL coating increased the mechanical strength of HA scaffolds. Besides, addition of graphene or MWCNTs further improved the compression strength of the constructs when they were used at 0.25 wt% and a decrease was observed at higher graphene and MWCNT concentrations. Highest mechanical performance was obtained in composite HA scaffolds involving MWCNTs. In vitro acellular bioactivity experiments revealed that both graphene and MWCNT-incorporated HA scaffolds showed higher bioactivity in simulated body fluid compared to bare scaffolds. However, HA formation ability was more pronounced with MWCNTs compared to graphene nanoflakes where they were possibly acted as an effective nucleation sites to induce the formation of a biomimetic apatite. Additionally, scaffolds prepared in the study were found to be nontoxic to the mouse bone marrow mesenchymal stem cells

CERAMICS INTERNATIONAL

Fibrous scaffolds have gained increasing attention in tissue engineering applications because of their high porosity, and surface area. In the current study cerium or gallium- containing silicate based 13-93 bioactive glass fibers were prepared using electrospinning approach. Effect of cerium and gallium substitution (up to 5 w%) on the in vitro bioactivity, pre-osteoblast cell response and antibacterial activity of the prepared fibers were assessed. Results revealed that, addition of cerium or gallium has no negative effect on bioactivity and hydroxyapatite forming ability of the glass in long term. The biocompatibility tests on MC3T3-E1 cells using XTT assay revealed no cytotoxicity of the cerium- or gallium-containing bioactive glass fibers. The fibers prepared in the study showed no antibacterial response to the gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria. Fibrous scaffolds manufactured in the study may be considered for the use in soft tissue engineering applications in near future. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved

JOURNAL OF COMPOSITE MATERIALS

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 mu m) were prepared by foam replication method. In order to improve the mechanical properties, the scaffolds were coated and infiltrated with a poly(-caprolactone) (PCL) solution at different concentrations (5, 10, and 20wt%). 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

JOURNAL OF POROUS MATERIALS

In the study graphene-containing porous, three dimensional polycaprolactone (PCL) scaffolds were prepared by solvent casting-salt leaching and robocasting methods for tissue engineering applications. Graphene nanopowders in the form of nanoflakes were incorporated into the polymer matrix at different concentrations namely 1, 3, 5 and 10 wt%. The dichloromethane was used as the solvent and sodium chloride crystals were utilized as the water-soluble porogen for the formation of an interconnected porous network (with non-oriented pores) inside the composite scaffolds in solvent casting-salt leaching method. On the other hand, acetone was utilized as solvent and PCL solutions were prepared at 20 wt% in robocasting method to construct scaffolds (with oriented pores) having a grid-like structure. The biological response of bone marrow mesenchymal stem cells seeded on these composite constructs having different architecture were tested using MTT method, live-dead cell viability assay and Alcian blue stanining. Cytotoxicity experiments revealed that mesenchymal stem cells did not show toxic response to composite robocast scaffolds. Cells proliferate and differentiate well on the surface of the robocast scaffolds compared to solvent-cast scaffolds under the same conditions. Results showed that scaffolds prepared in the study have potential to be used in cartilage tissue engineering in the presence of electric stimulation

MATERIALS TECHNOLOGY

Silicate-based bioactive glass constructs were fabricated by polymer foam replication method for tissue engineering applications. Composites were prepared by coating the surface of bioactive glass scaffolds with poly(epsilon-caprolactone) involving graphene nanopowders at different concentrations. In vitro bioactivity of the composite constructs was tested in simulated body fluid. Additionally, the response of pre-osteoblastic MC3T3-E1 and chondrogenic ATDC5 cells were investigated under in vitro conditions. Results revealed that a decrease was not observed in acellular bioactivity of the scaffolds. Cell viability experiments showed that graphene involving samples were not cytotoxic to the MC3T3-E1 and ATDC5 cells (except for the samples containing 10 wt% graphene) and cells proliferated well on the scaffolds. Additionally, the pre-osteoblastic cells seeded onto the composite scaffolds differentiated into osteoblasts. The scaffolds prepared in this study may find applications for bone and cartilage tissue engineering in the presence of electric stimulation

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE

Bioactive glasses are widely used in biomedical applications due to their ability to bond to bone and even to soft tissues. In this study, borate based (13-93B3) bioactive glass powders containing up to 5 wt% Ce2O3 and Ga2O3 were prepared by the melt quench technique. Cerium (Ce+3) and gallium (Ga+3) were chosen because of their low toxicity associated with bacteriostatic properties. Bioactive glass scaffolds were fabricated using the polymer foam replication method. In vitro degradation and bioactivity of the scaffolds were evaluated in SBF under static conditions. Results revealed that the cerium-and gallium-containing borate glasses have much lower degradation rates compared to the bare borate glass 13-93B3. In spite of the increased chemical durability, substituted glasses exhibited a good in vitro bioactive response except when the Ce2O3 content was 5 wt%. Taking into account the high in vitro hydroxyapatite forming ability, borate glass scaffolds containing Ce+3 and Ga+3 therapeutic ions are promising candidates for bone tissue engineering applications

JOURNAL OF THE AUSTRALIAN CERAMIC SOCIETY

In the current study cerium or gallium-containing silicate based 13-93 bioactive glass powders were prepared using sol-gel method. Cerium and gallium ions were chosen due to their well-known therapeutic actions and antimicrobial properties. Effect of cerium and gallium substitution (up to 5w%) on the in vitro bioactivity, and mechanical properties of the prepared powders and scaffolds were assessed. Results revealed that, additions of cerium or gallium has no significant negative effect for in vitro bioactivity and hydroxyapatite forming ability of the glass for long immersion times in simulated body fluid. An increase in mechanical properties was observed in cerium doped (>3%) glass samples presumably due to CeO2 formation during sintering. It was concluded that bioactive glass powders containing therapeutic metal ions prepared in the study via sol-gel process may find applications in biomedical applications in near future

CERAMICS INTERNATIONAL

The main objective of this study was to evaluate the cerium, gallium and vanadium-containing bioactive borate glass scaffolds for soft tissue applications and determine the potential toxicity of these scaffolds on the adjacent tissues. The effects of the cerium, gallium and vanadium substitution on the soft tissue ingrowth and angiogenesis in porous borate based bioactive glass scaffolds were investigated using rat subcutaneous implantation model. For this purpose, bioactive borate glass powders containing therapeutic ions were prepared by melt-cast method and subsequently scaffolds were fabricated using polymer foam replication technique. The scaffolds were implanted subcutaneously for 4 weeks in Sprague Dawley rats. Bare borate glass scaffolds with the same microstructure were used as the control. Histology was used to evaluate tissue ingrowth and blood vessel formation in the implants. Additionally, the antibacterial activities of cerium, gallium and vanadium containing porous bioactive glass scaffolds were investigated in vitro by a zone inhibition method. Results revealed that addition of cerium ions to the borate glass network caused an increase in blood vessel formation. On the other hand, a decrease was obtained in angiogenesis in gallium and vanadium-containing glasses. All of the scaffolds prepared in the study did not show any antibacterial activity towards Escherichia coli and Staphylococcus aureus. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved

MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS

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 degrees 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 degrees C. When immesed 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 XIT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfopheny1)-2H-Tetrazolium-5-Carboxanilide) assay was conducted to evaluate the osteoblast cell response to the bioactive glass fibers. (C) 2015 Elsevier B.V. All rights reserved

JOURNAL OF THE AUSTRALIAN CERAMIC SOCIETY

In this study, bioactive glass and hydroxyapatite (HA)-containing poly(epsilon-caprolactone) (PCL) nanocomposite fiber mats were fabricated through electrospinning. For this purpose, microscale bioactive glass (silicate-based 45S5 and borate-based 13-93B3 compositions) or HA particles (at 10 wt%) were incorporated into the PCL matrix. The fabricated biocomposite fibers were investigated in terms of morphological and chemical properties. An in vitro mineralization assay in simulated body fluid was performed to understand the capability of the composite electrospun fibers to induce the formation of hydroxycarbonate apatite. Results showed that the diameter of the electrospun PCL-based fibrous scaffolds increased by the inclusion of bioactive glass or HA particles. All of the fibrous mats prepared in the study showed hydrophobic character. Relatively high contact angles (> 90A degrees) obtained for fibrous scaffolds was attributed to the high porosity and surface roughness. Bioactive glass or HA addition to the PCL matrix enhanced the bioactivity of the fibrous scaffolds. The deposition rate of calcium phosphate-based material precipitates was higher on the surface of HA-containing samples compared to bioactive glass-containing PCL scaffolds. Additionally, mineralization ability of borate-based 13-93B3 glass-containing samples was higher compared to 45S5 glass-containing PCL fibers. The biocomposite fibrous scaffolds prepared in the study may find applications in wound healing as wound dressing and in bone tissue engineering