Magnesium- and strontium-co-substituted hydroxyapatite: the effects of doped-ions on the structure and chemico-physical properties

Abstract

The present study is aimed at investigating the contribution of two biologically important cations, Mg(2+) and Sr(2+), when substituted into the structure of hydroxyapatite (Ca(10)(PO(4))(6)(OH)(2),HA). The substituted samples were synthesized by an aqueous precipitation method that involved the addition of Mg(2+)- and Sr(2+)-containing precursors to partially replace Ca(2+) ions in the apatite structure. Eight substituted HA samples with different concentrations of single (only Mg(2+)) or combined (Mg(2+) and Sr(2+)) substitution of cations have been investigated and the results compared with those of pure HA. The obtained materials were characterized by X-ray powder diffraction, specific surface area and porosity measurements (N(2) adsorption at 77 K), FT-IR and Raman spectroscopies and scanning electron microscopy. The results indicate that the co-substitution gives rise to the formation of HA and β-TCP structure types, with a variation of their cell parameters and of the crystallinity degree of HA with varying levels of substitution. An evaluation of the amount of substituents allows us to design and prepare BCP composite materials with a desired HA/β-TCP ratio.

Cationic and Anionic Substitutions in Hydroxyapatite

“…The produced systems include the co-substitution of zinc/silver [209], silver/strontium [211], carbonate/strontium [492], carbonate/magnesium [454,493], carbonate/sodium [494], carbonate/silicate [495], yttrium/silicon [496], zinc/silicate [497], zinc/copper [498], strontium/cerium [499], magnesium/ strontium [500], magnesium/silver [501], and carbonate/silicate/magnesium [454]. However, the co-substitution of multiple (more than two) ions has not deeply and systematically attempted and investigated, and thus, it can be considered as a promising research field to be still and further explored and expanded [502,480].…”

Tuned Hydroxyapatite Materials for Biomedical Applications

“…This ability to incorporate ions through the doping is an alternative that is based on the fact that the introduction of small amounts of some ions can cause changes that improve the biological, physical-chemical, mechanical, and antimicrobial properties of the material [26,[29][30][31][32][33]. Thus, this study aims to present a search for articles and patent of technological inventions, which include information about hydroxyapatite in relation to its applications in the field of tissue engineering and doping with cerium ion for biomedical applications.…”

Ion-doping as a strategy to modulate hydroxyapatite nanoparticle internalization

“…The crystal lattice of HA is well known for accommodating a wide range of ionic substitutions among which carbonate and Mg stand out as major anionic and cationic elements found in bone minerals [30][31][32]. The incorporation of ionic substitutions into HA-NPs is well documented [30,33], but unfortunately many cell culture studies are lacking [34][35][36][37] or focus on one type of ion substitution, which makes it difficult to compare results. Studies are often also performed on compressed NPs in molds [18,[38][39][40].…”