Abstract: “The size and form of gold nanoparticles are crucial for the material properties. Particularly, anisotropic nanostructures are of particular interest because the capacity to enhance electromagnetic field upon irradiation for application in Surface Enhanced Raman Scattering spectroscopy and imaging. In the present study, biocompatible multibranched gold nanoparticles (MGNP) were synthesized by the one pot method using the piperazine moiety of HEPES buffer as reducing and stabilizing agent. The synthesis of MGNP was carried out at pH 3, 7 and 10 by using 0.2, 1.0, 2.5, 5.0 and 25.0 mM HEPES and phosphate buffer. The formation of stable MGNP in high yield was obtained using 2.5 mM HEPES buffer at pH values of 7.0 and 10.0 as evidenced by the deep blue color and the presence of red shifted resonance plasmon bands. The MGNP obtained in these conditions were used for association with cationic and anionic meso-tetrakis porphyrins, TMPyP (5, 10, 15, 20 tetrakis(1-metyl-4-pyridinio) porphyrin te”

Keywords: multibranched gold nanoparticles, green synthesis, plasmonic band, HEPES buffer, zeta potential, fluorescence