Noble metal nanoparticles have a great potential for biological study, especially the use of gold nanoparticles is very popular. In this work gold nanoparticles (GNPs), silver nanoparticles (SNPs) and goldsilver hybrid nanoparticles (HNPs) synthesized and used as a carrier for electrochemical investigation of redox protein. Optical characterization of these nanoparticles was performed by UV-Vis spectroscopy. The maximum of the plasmon band for GNPs, SNPs and HNPs (ratio of 1:1) are 524, 392 and 455 nm respectively. The optical absorption spectra of HNPs solution shows only one plasmon absorption, it is concluded that mixing of gold and silver leads to a homogeneous formation of alloy nanoparticles. LCR meter study shows the HNPs is best conductance in compare of GNPs and SNPs. Therefore, the electron transfer of the homogenous GOx, HRP and Hb was investigates by electrochemical method in presence of HNPs. They demonstrated quasi-reversible cyclic voltammograms with a formal potential of -479, -178 and -168 mV in 50 mM phosphate buffer solution at pH 7.4 respectively
