Effect of calcium phosphate synthesis conditions on its physico-chemical properties and evaluation of its antibacterial activity

Abstract

The antibacterial activity of non-stoichiometric calcium phosphate particles prepared by precipitation under controlled experimental conditions at pH ∼ 9 and sintered at high temperature was studied against Staphylococcus aureus bacteria. The effects of operating parameters developed according to an experimental design of Plackett-Burman type on the physicochemical characteristics and the capacity to inhibit bacterial growth were identified using a thermal analysis (TGA-DTA-DSC), x-ray Diffraction (XR), Raman Spectroscopy, Scanning Electron Microscope (SEM) and the Kirby Bauer Method. The XRD spectrum shows that the synthetic crystalline nanoparticles powders consist of multiphasic calcium phosphate β-TCP/β-CPP/OCP/HA and that the average particle size is between 56 and 123 nm calculated by the Debay-Shearer equation. The Raman spectrum of sintered powder shows the main absorption bands that are assigned to the asymmetric / symmetric P-O stretching vibrations in PO4−3 and the symmetric O-H stretching mode of the hydroxyl group in addition of Ca-PO4 and Ca-OH modes. The samples were found to possess different morphologies consisting of nano-rods of different lengths, semi / spherical structures and fine granules, in addition to irregular clusters. The antibacterial tests results showed that the high concentration calcium phosphate powder exhibited better antibacterial activity against Staphylococcus aureus bacteria with inhibition zones ranging from 0.2–0.7 cm.