Papers by Author: Gigliola Lusvardi

Abstract: Magnesium and strontium both play important roles in the growth of bone and so are desirable ions for substitution into hydroxyapatite (HA) intended for use as bioinstructive bone substitutes. A range of compositions were prepared by a solid state method based on the nominal composition of HA (Ca₁₀(PO₄)₆(OH)₂), with various levels of strontium and/or magnesium substitution: strontium-substituted HA (Ca₈Sr₂(PO₄)₆(OH)₂), magnesium-substituted HA (Ca_9.8Mg_0.2(PO₄)₆(OH)₂ and Ca₉Mg (PO₄)₆(OH)₂), and strontium and magnesium co-substituted HA (Ca_7.8Sr₂Mg_0.2(PO₄)₆(OH)₂ and Ca₇Sr₂Mg (PO₄)₆(OH)₂). Materials were characterised by powder X-ray diffraction, Fourier-transform infrared spectroscopy and Raman spectroscopy. These analyses indicated that the co-substituted materials were composed of mixtures of strontium-substituted hydroxyapatite and magnesium and strontium co-substituted β-tricalcium phosphate. In the magnesium-substituted materials, increased magnesium content was related to increased proportion of β-tricalcium phosphate phase, both with and without strontium co-substitution. The unsubstituted and strontium mono-substituted materials, however, were pure apatite phase, suggesting that magnesium was the destabilising factor in the phase compositions of the magnesium mono-substituted and magnesium and strontium co-substituted materials.

Abstract: This review presents a combined experimental-computational strategy for the development of potential bioactive zinc–containing silicate glasses and shows how sound relationships among the structural role of some key elements that appear to control bioactivity can by established and exploit for rational glass design.