Effect of pH on Hydroxyapatite Formation in Amino Acid Capped Gold Nanoparticles

Abstract

The gold nanoparticles were successfully synthesized using the chemical reduction method. The surface of gold nanoparticles was modified using three different charges of amino acid. The amino acid that used in this study was cysteine, arginine, and glutamic acid. The calcium and phosphate sources were added to amino acid capped gold nanoparticle solution to obtain hydroxyapatite. Hydroxyapatite is an inorganic material for teeth and bone tissue engineering. The morphological properties of the samples were investigated using Scanning Electron Microscope (SEM) and Field Emission Scanning Electron Microscope (FE-SEM). Different morphological characteristic was seen in different pH synthesis. The pH variation was normal pH that form in the solution and pH adjusted to 10 using NaOH in the hydroxyapatite formation. The elemental composition was also investigated using Energy-Dispersive X-ray (EDS) analysis. The elemental mapping was shown the homogeneity composition distribution of Ca and P on the sample pH adjustment that contains cysteine. The EDS results indicate the adjusted pH to 10 was potentially formed hydroxyapatite with a Ca/P ratio close to the theory.