Gold nanoparticles synthesis used for sensor applications

Gold nanoparticles (AuNPs) have a unique property called localized surface plasmon resonance (LSPR). LSPR excitation wavelength is strongly dependent on size of gold nanoparticles. At the LSPR wavelength, gold nanoparticles exhibit an enormous electric field enhancement extended from their surface. We have been synthesized gold nanoparticles using chemical reduction of hydrogen tetrachloroaurate (HAuCl4) with sodium borohydride (NaBH4). The soluble starch was used as a stabilizer. The pH of gold salt solution and concentration of stabilizer were varied to investigate the change of the size and stability of gold nanoparticles. Under basic condition, the gold ion was easily reduced to gold nanoparticles. Then, the smaller size of gold nanoparticles could be observed. The concentration of starch solution also affected on the size and stability of gold nanoparticles. The size of gold nanoparticles was increased with the decreasing of starch concentration. In this work, grating pattern of gold nanoparticles was prepared by imprinting method. There is a possibility to use the grating pattern of gold nanoparticles in SPR grating-coupling method.