THE INFLUENCE OF SR2+ AND AG+ DOPANTS ON LATTICE PARAMETER CHANGES AND APATITE FORMATION IN BIPHASIC CALCIUM PHOSPHATE

• Main Author: Mahfud, Maulana
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/82862
• Institution: Institut Teknologi Bandung

Biphasic calcium phosphate (BCP) is a composite consisting of a mixture of the less soluble HA (hydroxyapatite) phase and the more soluble ?-TCP (?-tricalcium phosphate) phase. The development of BCP has been widely pursued as a bone graft material, a coating for metal implants, a scaffold in tissue engineering, and for drug delivery. Efforts to enhance the biological properties of BCP have been made through the addition of polymers, bioactive glass, and ionic dopants. In this research, BCP doped with Sr2+ and Ag+ ions (BCP-SrAg) was synthesized, and the influence of these ions on the lattice parameters of BCP, as well as the apatite-forming ability of the product through in vitro testing, were analyzed. The BCP composite was obtained from HA and ?-TCP synthesized mechanochemically in a mass ratio of HA:?-TCP of 60:40. Pure HA was obtained from a precipitation reaction between Ca(NO3)2 solution and (NH4)2HPO4 solution, with a Ca/P ratio of 1.67, solution pH of 10, and the reaction carried out at 40 °C for 4 hours. ?-TCP was obtained from a precipitation reaction between Ca(NO3)2 solution and (NH4)2HPO4 solution, with a Ca/P ratio of 1.50, solution pH of 9, and the reaction carried out at 25 °C for 2 hours. The modification of HA doped with Sr2+ and Ag+ ions was performed by adding Sr(NO3)2 and AgNO3 at 10% of the molar amount of Ca(NO3)2 during the HA synthesis process. The resulting precipitate products were calcined at 800 °C for three hours. Lattice parameter analysis from the Powder X-ray Diffraction (PXRD) diffractogram of each product showed that the addition of Sr2+ ion dopant increased the lattice parameters a and c, whereas the addition of Ag+ dopant did not change the lattice parameters for HA and ?-TCP. Scanning Electron Microscope (SEM) results showed two groups of particles, with larger sizes (~4.6 ± 0.4 µm) and smaller sizes (~1.7 ± 0.2 µm), with BCP-SrAg having a relatively higher number of smaller-sized particle groups compared to BCP. Energy Dispersive Spectroscopy (EDS) spectrum analysis showed the presence of Sr2+ dopant at 1.65 ± 0.04 at% and Ag + at 0.09 ± 0.50 at% in BCP-SrAg. In vitro testing by immersing the product in simulated body fluid (SBF) was performed to determine the effect of dopant addition on apatite formation. SEM visualization results showed less apatite formation on BCP-SrAg, and EDS spectrum analysis indicated a decrease in the Ca/P ratio in BCP-SrAg after immersion