Colloidal gold nanoparticles currently have been utilized for many attractive applications in research and applied fields due to their interaction with visible light. More recently, these unique optical properties have been used in high-technology applications such as life science biosensors, Gas sensors, therapeutic agents, drug delivery in biological and medical applications, and catalysis. We have produced gold nanoparticles with tunable optical and electronic properties by controlling the size, shape, surface chemistry, or aggregation state.Colloidal Nanoparticles are of great importance in biology and industry. They are used in test strips for the detection of biological and drug delivery agents. These nanoparticles are used in characterization of DNA, antibodies and detection of biomolecular reactions. Additionally, they are used in various industries including optoelectronics, photonics, paint, textile and quantum computers. Colloidal Gold Nanoparticles is another product of Nanomanbna Iranian Co. which is used for reactivity with biomolecules. Gold colloidal particles include homogenous nanoparticles in various sizes from 5-100 nanometer.