New Phosphate Bioactive Glasses With Enhanced Thermal Properties For 3D Scaffold Processing Using Robocasting
Bhatti, Faheem Ahmed (2019)
2019
Sähkötekniikan DI-ohjelma - Degree Programme in Electrical Engineering
Lääketieteen ja terveysteknologian tiedekunta - Faculty of Medicine and Health Technology
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Hyväksymispäivämäärä
2019-12-03
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-201911045721
https://urn.fi/URN:NBN:fi:tuni-201911045721
Tiivistelmä
Phosphate bioactive glasses are the potential substitutes of typical silicate bioactive glass-es for repair and regeneration of the defected bone due to their resemblance to the natural bone. In earlier studies, thermal, bioactive and structural properties of different phosphate bio-active glasses were investigated by introducing various elements. Furthermore, in some stud-ies these glasses were utilized in scaffolds fabrication using methods like powder technique and foaming technique. But these techniques produced scaffolds with reduced mechanical properties due to large pores size.
In this thesis, new phosphate bioactive glasses with compositions; 45P2O5, 2.5B2O3, 2.5SiO2, 10Na2O, 20CaO, (20-x)SrO, xMgO in mol% (x = 0, 5 ,10, 15 and 20) were prepared with two particle sizes i.e. <38µm and 125-250µm. The aim was to develop phosphate bioac-tive glasses that can be sintered without losing their bioactivity. Thermal analysis was per-formed for these glasses in which glass transition and crystallization temperatures were in-creased with increasing amount of MgO. By further increasing the MgO content from 15 and 20 mol%, crystallization peaks disappeared. Bioactivity studies were performed in Simulated Body Fluid (SBF) at 37°C. The ion release profile was highly function of the particles size, as can be expected from glasses. A rapid ion release, within 1 day was seen for the smaller par-ticle size. Larger particle size, 125-250µm, released ions continuously for 2 weeks. FTIR of the glass structure revealed two new bands after 2 weeks time point, especially in the sample substituted with 20 mol% of MgO for SrO, that indicated CaP layer formation.
Based on thermal and bioactive properties, suitable glass compositions were chosen i.e. x = 10 and 15. These compositions were subjected to scaffold fabrication using robocasting technique in which printing head movement was controlled by programmed printing script. Ink, prepared from glass powders and Pluronic F-127 binder, was extruded to get three-dimensional scaffolds and then further sintered to obtained mechanically stable, amorphous, scaffolds. In-vitro dissolution revealed the formation of CaP layer faster and prominent in x = 15 glass scaffold. Furthermore, mechanical strength of both compositional scaffolds remained in the range of cancellous bone compressive strength even after two weeks of immersion in SBF.
In this thesis, new phosphate bioactive glasses with compositions; 45P2O5, 2.5B2O3, 2.5SiO2, 10Na2O, 20CaO, (20-x)SrO, xMgO in mol% (x = 0, 5 ,10, 15 and 20) were prepared with two particle sizes i.e. <38µm and 125-250µm. The aim was to develop phosphate bioac-tive glasses that can be sintered without losing their bioactivity. Thermal analysis was per-formed for these glasses in which glass transition and crystallization temperatures were in-creased with increasing amount of MgO. By further increasing the MgO content from 15 and 20 mol%, crystallization peaks disappeared. Bioactivity studies were performed in Simulated Body Fluid (SBF) at 37°C. The ion release profile was highly function of the particles size, as can be expected from glasses. A rapid ion release, within 1 day was seen for the smaller par-ticle size. Larger particle size, 125-250µm, released ions continuously for 2 weeks. FTIR of the glass structure revealed two new bands after 2 weeks time point, especially in the sample substituted with 20 mol% of MgO for SrO, that indicated CaP layer formation.
Based on thermal and bioactive properties, suitable glass compositions were chosen i.e. x = 10 and 15. These compositions were subjected to scaffold fabrication using robocasting technique in which printing head movement was controlled by programmed printing script. Ink, prepared from glass powders and Pluronic F-127 binder, was extruded to get three-dimensional scaffolds and then further sintered to obtained mechanically stable, amorphous, scaffolds. In-vitro dissolution revealed the formation of CaP layer faster and prominent in x = 15 glass scaffold. Furthermore, mechanical strength of both compositional scaffolds remained in the range of cancellous bone compressive strength even after two weeks of immersion in SBF.