Ion Release Behavior and Apatite-Forming Ability of Sol-Gel Derived 70S30C Bioactive Glass with Magnesium/Zinc Substitution

In vitro biomineralization potential in simulated wound fluid and antibacterial efficacy of biologically-active glass nanoparticles containing B2O3/ZnO

In the present study, SiO₂-CaO-B₂O₃-ZnO (SCBZ), SiO₂-CaO-B₂O₃ (SCB), SiO₂-CaO-ZnO (SCZ) and SiO₂-CaO (SC) silicate-based glasses were synthesized by the sol-gel method to elucidate the influence of B₂O₃ and ZnO substitution on glass characteristics aiming to further use in wound healing applications. The amorphous nature, spherical-shaped morphology and nano-sized primary particles of glasses were revealed by XRD and SEM analysis. Moreover, investigating the antibacterial activity of glasses against E.coli and S.aureus bacteria indicated the improved antibacterial properties of SCBZ glass against both bacterial strains compared with SCB and SCZ glasses. Assessment of ion release revealed that the incorporation of zinc induces a more stable glass network with a lower tendency to dissolution contrary to the incorporation of boron, which facilitated the dissolution of glass by the formation of more reactive SiOB and BO bonds. Glasses were immersed in Simulated Wound Fluid (SWF) to predict their mineralization susceptibility. Morphological studies and FTIR analysis showed the formation of cauliflower-like hydroxy-carbonated apatite on the surface of SCB and SC glasses after 14 days. In contrast, the presence of Zn in SCBZ and SCZ glasses inhibited the formation of crystalline apatite and induced the deposition of spherical-shaped amorphous apatite. Our study suggests that the co-incorporation of B and Zn in SCBZ glass make this material a potential multifunctional candidate for accelerating the healing of skin wounds.

Understanding the composition-structure-bioactivity relationships in diopside (CaO·MgO·2SiO₂)-tricalcium phosphate (3CaO·P₂O₅) glass system

The present work is an amalgamation of computation and experimental approach to gain an insight into composition-structure-bioactivity relationships of alkali-free bioactive glasses in the CaO-MgO-SiO2-P2O5 system. The glasses have been designed in the diopside (CaO·MgO·2SiO2; Di)-tricalcium phosphate (3CaO·P2O5; TCP) binary join by varying the Di/TCP ratio. The melt-quenched glasses have been investigated for their structure by molecular dynamic (MD) simulations as well as by nuclear magnetic resonance spectroscopy (NMR). In all the investigated glasses silicate and phosphate components are dominated by Q(2) (Si) and Q(0) (P) species, respectively. The apatite forming ability of the glasses was investigated using X-ray diffraction (XRD), infrared spectroscopy after immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1 h and 14 days, while their chemical degradation has been studied in Tris-HCl in accordance with ISO 10993-14. All the investigated glasses showed good bioactivity without any substantial variation. A significant statistical increase in metabolic activity of human mesenchymal stem cells (hMSCs) when compared to the control was observed for Di-60 and Di-70 glass compositions under both basal and osteogenic conditions.