Highly Bioactive Sol-Gel-Derived Borate Glasses

Abstract

Attributable to their low chemical durability, borate-based glasses have been demonstrated to convert rapidly to hydroxy-carbonated apatite (HCA), the inorganic component of bone. However, the effect of sol-gel processing on the bioactivity of borate-based glasses has not been investigated. In this study, the gel and glass forming abilities of six different borate-based glass formulations with borate content ranging from 36 to 61 mol % and based on a previously studied four component melt-derived glass system [(46.1)B 2 O 3 −(26.9)CaO−(24.4)Na 2 O−(2.6)P 2 O 5 ; mol %] were investigated. Compared to melt-quench, sol-gel processing fabricated nanoporous glass particles with at least 2 orders of magnitude greater values for specific surface areas and total pore volumes, which translated to dramatically higher aqueous interaction and ion release rates. Surprisingly, when immersed in simulated body fluid, HCA conversion was achieved in as little as 3 h for sol-gel derived borate based glasses, demonstrating a 25-fold increase in mineralization rate when compared to melt derived equivalents. The ability of the sol-gel derived borate-based glasses to rapidly convert to bone-like HCA holds promise in numerous potential tissue engineering applications, including the repair and augmentation of mineralized tissues.

Novel Er3+/Ho3+‐codoped glass‐ceramic fibers for broadband tunable mid‐infrared fiber lasers

“…26,27 The bands situated at 774 and 1450 cm À1 are related to the stretching vibration of BO 4 and BO 3 units, separately. 28,29 However, the Raman spectra of GC fiber cores show intensive peaks (173, 208, and 262 cm À1 ) that are consistent with the vibrational modes of NaYF 4 crystal, indicating the precipitation of NaYF 4 nanocrystals in the fiber core. 30 These results are in good agreement with those of precursor glasses and GCs in the case of the same heat-treatment temperature (Figure S1B,D).…”

“…The bands located at 476 and 995 cm −1 are responsible for the Si–O–Si stretching or bending vibration . The bands situated at 774 and 1450 cm −1 are related to the stretching vibration of BO 4 and BO 3 units, separately . However, the Raman spectra of GC fiber cores show intensive peaks (173, 208, and 262 cm −1 ) that are consistent with the vibrational modes of NaYF 4 crystal, indicating the precipitation of NaYF 4 nanocrystals in the fiber core .…”

Bioactive calcium phosphate–based glasses and ceramics and their biomedical applications: A review

“…139 In vitro bioactivity of glasses especially for borate glasses has been evaluated in aqueous K 2 HPO 4 medium. 57,92,131,152 This medium was used to save the experimental time through the reaction of available ${\mathrm{HPO}}_4^{2-}$ and OH − ions in K 2 HPO 4 solution with glasses. 92 …”

Characterization of the conversion of bone cement and borate bioactive glass composites

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