Synthesis and characterisation of nanophase hydroxyapatite co-substituted with strontium and zinc. Issue 7 (May 2018)

• Record Type: Journal Article
• Authors: Lowry, N.; Brolly, M.; Han, Y.; McKillop, S.; Meenan, B.J.; Boyd, A.R.
• Is Part Of: Ceramics international. Volume 44:Issue 7(2018)
• Page Start: 7761
• Page End: 7770
• Publication Date: 2018-05
• Subjects: Bioceramic -- Nano-hydroxyapatite -- Co-substitution -- Strontium -- Zinc; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.01.206
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: In order to develop new bioactive calcium phosphate (CaP) materials to repair bone defects, it is important to ensure these materials more closely mimic the non-stoichiometric nature of biological hydroxyapatite (HA). Typically, biological HA combines various CaP phases with different impurity ions, which substitute within the HA lattice, including strontium (Sr 2+ ), zinc (Zn 2+ ), magnesium (Mg 2+ ), carbonate (CO3 2- ) and fluoride (F - ), but to name a few. In addition to this biological HA have dimensions in the nanometre (nm) range, usually 60 nm in length by 5–20 nm wide. Both the effects of ion substitution and the nano-size crystals are seen as important factors for enhancing their potential biofunctionality. The driving hypothesis was to successfully synthesise nanoscale hydroxyapatite (nHA), co-substituted with strontium (Sr 2+ ) and zinc (Zn 2+ ) ions in varying concentrations using an aqueous precipitation method and to understand their chemical and physical properties. The materials were characterised using Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM) techniques. The FTIR, XRD and XPS results confirmed that the nHA was successfully co-substituted with Sr 2+ and Zn 2+, replacing Ca 2+ within the nHA lattice at varying concentrations. The FTIR results confirmed that all of the samples were carbonated, with a significant loss of hydroxylation as a consequence of the incorporation of Sr 2+ and Zn 2+ into the nHA lattice. The TEM results showed that each sample produced was nano-sized, with the Sr/Zn-10%nHA having the smallest sized crystals approximately 17.6 ± 3.3 nm long and 10.2 ± 1.4 nm wide. None of the materials synthesised here in this study contained any other impurity CaP phases. Therefore, this study has shown that co-substituted nHA can be prepared, and that the degree of substitution (and the substituting ion) can have a profound effect on the attendant materials' properties.