Preparasi dan Sifat Mekanik dari Hidroksiapatit terko-substitusi Zinc dan Strontium

Abstract

Hydroxyapatite (HA) is a biomaterial with biocompatibility properties and a chemical composition similar to natural bone, making it suitable for use as a bone implant. Hydroxyapatite has high flexibility in accepting other ions to substitute for ions present in the hydroxyapatite structure, such as zinc ions (Zn2+) and strontium ions (Sr2+), which replace calcium ions (Ca2+) in hydroxyapatite. Substituting zinc and strontium in hydroxyapatite can enhance osteoblast activity and reduce osteoclast activity. This study aims to explore the properties of ZnSrHA material by observing changes in the formed crystal structure. In this research, hydroxyapatite was synthesized with ion substitution of zinc and strontium at various substitution levels: 0%, 0.5%, 2.5%, and 5%, using the precipitation method and calcined at 1000°C for 2 hours. In the ZnSrHA samples, zinc and strontium ions have been successfully substituted into the hydroxyapatite structure according to their substitution levels. The substitution of zinc and strontium ions can also be seen based on the calcium phosphate (Ca/P) molar ratio, which ranges from 1.47 to 1.67. Non-calcined ZnSrHA is multiphasic, consisting of hydroxyapatite and 𝛽-tricalcium phosphate (𝛽-TCP) phases. Both non-calcined and calcined ZnSrHA exhibit absorption spectra and characteristic functional groups of hydroxyapatite. The addition of various substitution levels and calcination leads to a tendency for the wavenumber to broaden. From FESEM observations, it is known that the morphology of synthesized HA particles appears acicular for non-calcined samples, but it is not well-observed due to particle agglomeration. For calcined samples, the morphology appears spherical. Furthermore, the addition of various substitution levels affects the compressive strength of hydroxyapatite samples; higher substitution levels lead to increased compressive strength for each variation. Compressive strength and stiffness tests show an increasing trend with higher substitution levels. This indicates that the addition of substitution levels significantly influences the crystal size of the resulting HA.