Accelerated Conversion of Silicate Bioactive Glass (13‐93) to Hydroxyapatite in Aqueous Phosphate Solution Containing Polyanions

Fu, Qiang; Rahaman, Mohamed N.; Day, Delbert E.

doi:10.1111/j.1551-2916.2009.03315.x

Cited by 19 publications

(19 citation statements)

References 19 publications

(65 reference statements)

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“…Furthermore, the presence of proteins, polysaccharides and other polymeric species in the extracellular matrix which contain electron‐donating moieties such as carboxyl and hydroxyl groups could also contribute to the more rapid in vivo degradation of these glasses. In a previous in vitro study, the addition of polyanion species (such as alginic acid) to a PBS was shown to markedly increase the conversion of 13‐93 glass to HA 9…”

Section: Discussionmentioning

confidence: 96%

Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation

Fu¹,

Rahaman²,

Bal³

et al. 2010

J Biomedical Materials Res

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169

132

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In Part I, the in vitro degradation of bioactivAR52115e glass scaffolds with a microstructure similar to that of human trabecular bone, but with three different compositions, was investigated as a function of immersion time in a simulated body fluid. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. This work is an extension of Part I, to investigate the effect of the glass composition on the in vitro response of osteogenic MLO-A5 cells to these scaffolds, and on the ability of the scaffolds to support tissue infiltration in a rat subcutaneous implantation model. The results of assays for cell viability and alkaline phosphatase activity showed that the slower degrading silicate 13-93 and borosilicate 13-93B1 scaffolds were far better than the borate 13-93B3 scaffolds in supporting cell proliferation and function. However, all three groups of scaffolds showed the ability to support tissue infiltration in vivo after implantation for 6 weeks. The results indicate that the required bioactivity and degradation rate may be achieved by substituting an appropriate amount of SiO2 in 13-93 glass with B2O3, and that these trabecular glass scaffolds could serve as substrates for the repair and regeneration of contained bone defects.

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Section: Discussionmentioning

confidence: 96%

Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation

Fu¹,

Rahaman²,

Bal³

et al. 2010

J Biomedical Materials Res

Self Cite

169

132

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show abstract

“…8, at 6 weeks, the converted layer in vivo (34 ± 6 μm) was much larger than that in vitro (~5 μm). The faster conversion in vivo has been explained in terms of the more dynamic environment and the presence of electrolytes, proteins and biological polymers in vivo [49, 50]. …”

Section: Discussionmentioning

confidence: 99%

Mechanical properties of bioactive glass (13-93) scaffolds fabricated by robotic deposition for structural bone repair

et al. 2013

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There is a need to develop synthetic scaffolds for repairing large defects in load-bearing bones. Bioactive glasses have attractive properties as a scaffold material for bone repair, but data on their mechanical properties are limited. The objective of the present study was to comprehensively evaluate the mechanical properties of strong porous scaffolds of silicate 13-93 bioactive glass fabricated by robocasting. As-fabricated scaffolds with a grid-like microstructure (porosity = 47%; filament diameter = 330 μm; pore width = 300) were tested in compressive and flexural loading to determine their strength, elastic modulus, Weibull modulus, fatigue resistance, and fracture toughness. Scaffolds were also tested in compression after they were immersed in simulated body fluid (SBF) in vitro or implanted in a rat subcutaneous model in vivo. As fabricated, the scaffolds had a strength = 86 ± 9 MPa, elastic modulus = 13 ± 2 GPa, and a Weibull modulus = 12 when tested in compression. In flexural loading, the strength, elastic modulus, and Weibull modulus were 11 ± 3 MPa, 13 ± 2 GPa, and 6, respectively. In compression, the as-fabricated scaffolds had a mean fatigue life of ~106 cycles when tested in air at room temperature or in phosphate-buffered saline at 37 °C under cyclic stresses of 1–10 MPa or 2–20 MPa. The compressive strength of the scaffolds decreased markedly during the first 2 weeks of immersion in SBF or implantation in vivo, but more slowly thereafter. The brittle mechanical response of the scaffolds in vitro changed to an elasto-plastic response after implantation for longer than 2–4 weeks in vivo. In addition to providing critically needed data for designing bioactive glass scaffolds, the results are promising for the application of these strong porous scaffolds in loaded bone repair.

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“…5). The faster conversion of 13–93 bioactive glass in vivo presumably resulted from the more dynamic environment of the body (compared to the more static in vitro system), and the presence of electrolytes, proteins, and biological polymers in the body fluid [34, 35]. …”

Section: Discussionmentioning

confidence: 99%

Bone regeneration in strong porous bioactive glass (13-93) scaffolds with an oriented microstructure implanted in rat calvarial defects

2013

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There is a need for synthetic bone graft substitutes to repair large bone defects resulting from trauma, malignancy, and congenital diseases. Bioactive glass has attractive properties as a scaffold material but factors that influence its ability to regenerate bone in vivo are not well understood. In the present work, the ability of strong porous scaffolds of 13–93 bioactive glass with an oriented microstructure to regenerate bone was evaluated in vivo using a rat calvarial defect model. Scaffolds with an oriented microstructure of columnar pores (porosity = 50%; pore diameter = 50–150 µm) showed mostly osteoconductive bone regeneration, and new bone formation, normalized to the available pore area (volume) of the scaffolds, increased from 37% at 12 weeks to 55% at 24 weeks. Scaffolds of the same glass with a trabecular microstructure (porosity = 80%; pore width = 100–500 µm), used as the positive control, showed bone regeneration in the pores of 25% and 46% at 12 and 24 weeks, respectively. The brittle mechanical response of the as-fabricated scaffolds changed markedly to an elasto-plastic response in vivo at both implantation times. These results indicate that both groups of 13–93 bioactive glass scaffolds could potentially be used to repair large bone defects, but scaffolds with the oriented microstructure could also be considered for the repair of loaded bone.

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Accelerated Conversion of Silicate Bioactive Glass (13‐93) to Hydroxyapatite in Aqueous Phosphate Solution Containing Polyanions

Cited by 19 publications

References 19 publications

Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation

Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation

Mechanical properties of bioactive glass (13-93) scaffolds fabricated by robotic deposition for structural bone repair

Bone regeneration in strong porous bioactive glass (13-93) scaffolds with an oriented microstructure implanted in rat calvarial defects

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