Low-temperature sintering of 45S5 Bioglass®-based glass ceramics: Effect of biphasic mixing approach on the mechanical and biological properties

• In situ gel- and mechanical-mixing of 45S5 Bioglass with B2O3/ZnO-rich bioglass (BG-ZB) is studied.
• 45S5-based glass-ceramic is fabricated via BG-ZB-assisted low-temperature sintering technique.
• In situ gel-mixing shows superior mechanical strength in comparison with that of mechanical mixing.
• 45S5/BG-ZB composites sinted at 860–920 °C show faster biodegradation than the sintered pure 45S5.

The effects of biphasic mixing approaches on the mechanical strength and in vitro biological properties of 45S5 BG-derived bioactive glass-ceramics (BGC) sintered at a temperature range of 860–980 °C were investigated. The sol–gel-derived ZnO/B2O3-rich bioactive glass (BG-ZB) exhibited a low melting temperature (~860 °C) and nanoscale particle size distribution (50–670 nm). For the in situ mixing of 45S5 BG particles with the precursor hydrogel of BG-ZB before drying, compressive strength (4.5-fold) and bending strength (3.1-fold) of the 45S5/BG-ZB composite significantly higher than the pure 45S5 BGC were achieved at an appropriate sintering temperature of 920 °C, whereas the conventional mechanical mixing of 45S5 BG particles with the BG-ZB nanoparticles resulted in minor strength enhancement. in vitro immersion tests revealed some similarities in surface bioactivity in simulated body fluid and biodegradation in Tris buffer, between the BGC composites prepared by the two mixing approaches. These results suggest that the distribution homogeneity of the BG-ZB phase in 45S5 matrix is mainly responsible for the mechanical strength, but does not compromise their biologically relevant performances.

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