MODIFICATION OF HYDROXIAPATITES WITH MAGNESIUM USING CALCIUM FROM BLOOD BLOOD SKIN (Tegillarca granosa) AND TEST OF ANTIBACY ACTIVITY Abdillah Adam Siregar; Prof. Dr. Novesar Jamarun *, MS; Dr. Eng. Yulia Eka Putri * * Counselor E-mail: abdillahadam18@gmail.com Department of Chemistry FMIPA UNAND Materials Chemistry Laboratory Andalas University Abstract: Hydroxyapatite (HAp) is a major component in bone and tooth preparation. HAp is widely used to repair, replenish, expand, and reconstruct damaged bone tissue. In this study, magnesium-modified HAp and Hap (Mg-Hap) were synthesized from the shell of blood clams using the sol gel method. The synthesis results show that HAp is formed at an alkaline pH. XRF test results obtained composition of CaO from calcined clam samples of 98.326%. The XRD characterization results show the formation of HAp and Mg-HAp phases with maximum magnesium addition is 20%, and Mg-HAp 10% has the highest crystallinity. The results of Scanning Electron Microscope (SEM) show that the particle shape produced on Mg-Hap 10% is rice-like shape while Mg-Hap 20% is round with rough surface. Antibacterial activity test showed Hydroxyapatite has higher activity against Staphylococcus aureus (S. aureus) bacteria than Escherichia coli (E. coli) bacteria and highest antibacterial activity shown by Mg-Hap 10%. Keywords: Hydroxyapatite, Blood Scale, Magnesium, Sol-Gel, Antibacterial I. Introduction Hydroxyapatite [Ca10(PO4)6(OH)2] is the preferred material for various biomedical applications such as orthopedics, dentistry, antimicrobial and drug delivery, due to the similarity of composition to bone mineral phases, excellent biocompatibility, and the ability to assist cell function, Expression and osteoconductivity 1 . Raw materials that can be used to make hydroxyapatites are found in nature, such as limestone, eggshells, coral and shells. The production of shellfish in Indonesia is increasing year by year. However, this seafood commodity, especially the shells of seashell has not been optimally utilized. The advantages of the use of this shell is to increase the value of shellfish, reduce the solid waste in the environment and the utilization of natural materials as substitution of bone components. Therefore, this idea is a potential solution to be developed for the synthesis of hydroxyapatite 2 . In recent years, control of microbial populations has become a problem that threatens global health security. The microorganisms that cause many diseases have become resistant to various antimicrobial drugs. Therefore, the spread of antimicrobial resistance must be minimized. The development of new antibacterial agents, drugs, vaccines and strategies in nanotechnology is needed. Many researchers have developed material with antimicrobial properties through the incorporation of nanotechnology and materials science. Several alternatives have been studied, including the use of nanoparticles, some of the inevitable problems encountered are toxicity and biocompatibility. The antibacterial efficiency of nanoparticles depends on the type of material used for the synthesis and size of the nanoparticles. Various types of nanoparticles and their derivatives have received much attention due to their potential antibacterial effects, including magnesium oxide nanoparticles (MgO). Synthesized hydroxyapatite synthesis with magnesium can produce a biocompatible antimicrobial agent and good antibacterial properties 3 .