Strontium and zinc co-substituted nanophase hydroxyapatite. Issue 15 (15th October 2017)

• Record Type: Journal Article
• Authors: Lowry, N.; Han, Y.; Meenan, B.J.; Boyd, A.R.
• Is Part Of: Ceramics international. Volume 43:Issue 15(2017)
• Page Start: 12070
• Page End: 12078
• Publication Date: 2017-10-15
• Subjects: Co-substitution -- Strontium -- Zinc -- Hydroxyapatite -- X-ray Photoelectron Spectroscopy (XPS) -- X-ray Diffraction (XRD) -- Nano-hydroxyapatite; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2017.06.062
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: It is well documented that biological hydroxyapatite (HA) differs from pure and synthetically produced HA, and contains of a mixture of calcium phosphate (CaP) phases in addition to a range of impurity ions, such as strontium (Sr 2+ ), zinc (Zn 2+ ), magnesium (Mg 2+ ), fluoride (F - ) and carbonate(CO3 2- ), but to name a few. Further to this, biological apatite is generally in the form of rod (or needle-like) crystals in the nanometre (nm) size range, typically 60 nm in length by 5–20 nm wide. In this study, a range of nano-hydroxyapatite (nHA), substituted nHA materials and co-substituted nHA (based on Sr 2+ and Zn 2+ ) were manufactured using an aqueous precipitation method. Sr 2+ and Zn 2+ were chosen due to the significant performance enhancements that these substitutions can deliver. The materials were then characterised using Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM) techniques. The TEM results show that all of the samples produced were nano-sized, with Zn-substituted nHA being the smallest crystals around 27 nm long and 8 nm wide. The FTIR, XRD and XPS results all confirm that the materials had undergone substitution with either Sr 2+ and Zn 2+, for Ca 2+ within the HA lattice (or both in the case of the co-substituted materials). 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 HA lattice. None of the materials synthesised here in this study contained any other impurity CaP phases. Therefore this study has shown that substituted and co-substituted nanoscale apatites can be prepared, and that the degree of substitution (and the substituting ion) can have a profound effect of the attendant materials' properties.