Improving the mechanical properties of strontium nitrate doped dicalcium phosphate cement nanoparticles for bone repair application

Abstract

Advances in the science and technology of bone materials and cements have been expanded over the past several years. The combination of reinforcing materials with bone cement has been proven with the increase in strength and biocompatibility of the porous scaffold. The aim of this study was to investigate and compare four specific types of the scaffold. The effect of strontium nitrate on dicalcium phosphate (DCaP) bone cements made by co-precipitation method was investigated. In this study, a pure sample of brushite (Br) and strontium nitrate containing (3 wt%, 7 wt%, and 10 wt%) were prepared. The phase composition of the samples was examined by X-ray diffraction (XRD) and their microstructure and morphology were examined using field emission scanning electron microscopy (FESEM) technique. The bioactivity of the samples was evaluated in the simulated body fluid (SBF) and the biodegradability of the samples was measured in the phosphate buffer saline (PBS). The mechanical properties of the sample such as compressive strength and elastic modulus were investigated. Bioactivity and biodegradability tests confirm the result of compressive strength. The SEM images showed that the prepared scaffolds were porous with 55–65% porosity and the interconnected porosity dimention is around 50–100 μm. The obtained results indicated that with increasing hydroxyapatite (HA) and brushite in the nanocomposite, the porosity increased, the size of the porous decreased and the elastic modulus increased. The results of cell culture indicated biocompatibility and non-toxicity of the synthesized scaffolds increased more than 0.989. Also, the ultimate strength of brushite-dicalcium phosphate cements depends on the degree of cement conversion, the porosity of the cement, the size of the crystal and the filler particles. The sample containing 3 wt% strontium nitrates with hydroxyapatite (HA) and brushite (Br) showed proper mechanical and biological properties before and after immersion in SBF solution.