Gold Nanoparticles and its Preparation

Abstract

Among the colorimetric detection tactics, metallic nanoparticle based detection is gaining more attention due to quickness and less resource requirement at the point of use. Unique chemical inertness, shape, size and optical attributes of gold nanoparticles (GNPs) make them ideal for various diagnostic tools. In this approach synthesized GNPs were tabilized by citrate counter ions. These GNPs were characterized for their optical properties, shape, size, zeta potential, and dynamic light scattering. Absorption maxima (λmax) were observed at 519.8 nm with the average particle size of 34.8 nm. Transmission electron microscopy also revealed that the average size of GNPs were about 35 nm. Negative zeta potential (– 43.2 mV) indicates presence of negative charge at the surface of GNPs. To find the stability of GNPs in buffer, two buffers (borate and phosphate) having different pH (6.5, 7.5 and 8.5) and same molarity (0.1 M) were evaluated with a purpose to determine the suitable buffer required for conjugation of GNPs to antibody for lateral flow assays. Keywords: Antibody, citrate reduction, dynamic light scattering, gold nanoparticles, size distribution zeta potential