Rapid conversion of highly porous borate glass microspheres into hydroxyapatite

Islam, Md Towhidul; Macri-Pellizzeri, Laura; Sottile, Virginie; Ahmed, Ifty

Abstract

This paper reports on the rapid development of porous hydroxyapatite (HA) microspheres with large external pores and fully interconnected porosity. These porous microspheres were produced by converting borates glasses (namely 45B5, B53P4 and 13-93B) into HA by immersing them in potassium phosphate media and simulated body fluid (SBF). Solid (SGMS) non-porous and highly porous (PGMS) microspheres were prepared from borate glasses via a novel flame spheroidisation process and their physicochemical properties including in vitro biological response were investigated. Morphological and physical characterisation of the PGMS showed interconnected porosity (up to 75 ± 5%) with average external pore sizes of 50 ± 5 μm. Mass loss, ion release, X-ray diffraction (XRD) and Scanning electron microscopy (SEM) analysis confirmed complete conversion to HA in 0.02 M K2HPO4 solution for the PGMS (with exception of 13-93B glass) and at significantly faster rates compared to their SGMS counterparts. However, 13-93B microspheres only converted to HA in Na2HPO4 solution. The in vitro SBF bioactivity studies for all the borate compositions showed HA formation and much earlier for PGMS compared to SGMS. Direct cell culture studies using hMSCs revealed that the converted porous HA microspheres showed enhanced pro-osteogenic properties compared to their unconverted counterparts and such are considered as highly promising candidate materials for bone repair (and orthobiological) applications.

Citation

Islam, M. T., Macri-Pellizzeri, L., Sottile, V., & Ahmed, I. (2021). Rapid conversion of highly porous borate glass microspheres into hydroxyapatite. Biomaterials Science, 9(5), 1826-1844. https://doi.org/10.1039/d0bm01776k

• Journal Article Type: Article
• Acceptance Date: Jan 11, 2021
• Online Publication Date: Jan 13, 2021
• Publication Date: Jan 13, 2021
• Deposit Date: Jan 20, 2021
• Publicly Available Date: Jan 20, 2021
• Journal: Biomaterials Science
• Electronic ISSN: 2047-4849
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 5
• Pages: 1826-1844
• DOI: https://doi.org/10.1039/d0bm01776k
• Keywords: General Materials Science; Biomedical Engineering
• Public URL: https://nottingham-repository.worktribe.com/output/5247920
• Publisher URL: https://pubs.rsc.org/en/content/articlelanding/2021/bm/d0bm01776k#!divAbstract