Preparation of Injectable Dicalcium Phosphate Bone Cement for Potential Orthopedic Applications

Various natural wastes can be promising for mining more valuable compounds if some specialized extraction techniques are adopted. Hydroxyapatite (HA) is a significant biomaterial that can be extracted from waste bovine bones by heating them at 700 °C and 900 °C. Based on this idea, we made a novel dicalcium phosphate (DCP) bone cement (BC) by extracting HA via the reaction with monocalcium phosphate monohydrate (MCPM) and trisodium citrate. The setting time, injectability, and compressive strength (CS) of this DCPBC were examined using various analytical techniques, such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) attached with energy-dispersive X-ray (EDX) spectroscopy, and Fourier-transformed infrared spectroscopy (FTIR). The phase composition, surface morphology, and chemical compositions of HA and DCP were evaluated. A Gillmore needle apparatus was used to measure the initial and final setting times of the specimens. The CS values of the prepared specimens were determined using INSTRON Series IX. The in vitro dissolution behavior of all samples was evaluated by immersing them in simulated body fluid (SBF) over 7 days at 37 °C. The final setting times of samples 3, 4, and 5 were 20, 24, and 18 min, respectively. In addition, the CS value of sample 1 before immersion in SBF was much lower (1.23 MPa) compared to sample 5 (21.79 MPa) after 7 days of immersion. The CS of the DCP after 3 days of immersion was increased to 33.75 MPa. The in vitro results for the dissolution and bioactivity of HA showed the highest degradation rate after 1 day of immersion and then decreased with the increase in the immersion duration. The HA layer thickness was considerably improved with longer incubation times. The proposed injectable DCP bone cement may have potential in future orthopedic applications.