Bone bonding augmentation and synergetic attitude of gamma-irradiated modified borate bioglass

Abstract

Samples from modified borate Hench's bioglass of nominal composition (45B2O3-24.5Na2O-24.5CaO–6P2O5 wt. %) were successfully synthesized. Both effects of varying gamma irradiation doses (1–10 M rad) and varying dipping times in Simulated Body Fluid (1–4 weeks) were simultaneously studied through different techniques. FTIR resultant spectra of the considered bio-borate glass show bands in the range 410–1600 cm−1 the appearance of small peaks at 1640, 2850 and 2940 cm−1 after irradiation that confirm the existence of the main vibrational units of both triangular and tetrahedral borate groups and minor phosphate groups. XRD for the exposed samples with different doses reveals minor variations in the diffractograms indicating the stability of the constituting component structural units and increase in the hydroxyapatite (HA) hexagonal phase patterns. FTIR spectra after immersion for prolonged times either before and after gamma irradiation show formation of characteristic two far-IR peaks at about 730 and 550 cm−1 together with the formation or increase in the intensity of the peaks at 3445 and 1650 cm−1 due to OH, BOH or POH groups that approve formation of (HA) through the various corrosion steps including hydrolysis, reaction or dissolution of the modifier components and the ultimate interactions to form the calcium phosphate (HA) phase. SEM images confirm the appearance of rounded or nodular-shaped microcrystals especially after extended immersion times. The fraction of four coordinated borons (N4) N4 was observed to increase with immersion time due to the continuous corrosion process including hydration, solubility, besides the fact that the 3-coordinated borons are assumed to be more soluble than compact four-coordinated borons.