Effect of carbonization treatment on the morphology and microstructure of mesoporous bioactive glass/nanocrystalline hydroxyapatite nanocomposite

• Increase of carbonization temperature is favorable for the deposition of HA clusters in MBG–nHA composites.
• Increase of carbonization temperature results in the decrease of pore volume and surface area.
• MBG–nHA nanocomposites with appropriate carbon sphere content and low carbonization temperature show high bioactivity.

Mesoporous bioactive glass/nanocrystalline hydroxyapatite (MBG–nHA) nanocomposite synthesis was prepared through evaporation-induced self-assembly method followed by in situ carbonization process, with non-ionic block copolymer as mesoporous template and carbon sphere as co-template. Conducting carbonization before calcination provided an effective and simple method of controlling the structural and morphological features of MBG–nHAs. The results show that the MBG–nHA350 nanocomposite with low carbonization temperature possessed a relatively ordered hexagonal structure, high specific surface area, and large pore volume. The increment of carbonization temperature induced the presence of micropores on the surface of the nanocomposite and increased the HA nanoparticles. These findings suggest that the surface area and pore volume of the nanocomposite decrease with increasing carbonization temperature. The structural changes in the nanocomposites were related to the inclusion of HA nanoparticles in the channels through carbonization. The in vitro bioactivity evaluation in the simulated body fluid (SBF) confirms that the MBG–nHA350 sample exhibits fast apatite formation ability, thereby denoting that the proposed method enhances the potential application of MBG–nHAs in bone tissue regeneration and drug delivery.