Description
Gold nanoparticles (AuNPs) ranging from 2-200nm in diameter find applications in diverse fields.They show excellent biocompatibility and attractive physicochemical properties. AuNPs, as aggregates, are shown to be highly sensitive colloidal biosensors. Poly (ethylene) glycol (PEG) surface coatings on gold nanoparticles help in the reduction of protein adsorption, reduce nonspecific interactions with cells and greatly improve the pharmokinetics of these nanoparticles and disables aggregation of the nanoparticles. PEG layer density depends inversely on the AuNPs curvature. Denser coating was possible on smaller AuNPs. AuNPs coated with PEG 5000 exhibited highest colloidal stability. The methyl group, being hydrophobic, acts as a protecting shield between the gold nanoparticles and the hydrophilic outer PEG coating and also leads to a further reduction of protein adsorption and macrophage uptake by the AuNPs.Several other specific applications have been listed below:Since they adhere to cell membranes, AuNPs can be used in cellular and intracellular targeting in targeted drug delivery applications and also used in biodistribution studies.AuNPs can be used in photothermal therapy and radiotherapy.Studies show that 30-nm PEG-coated AuNPs have been successfully used to deliver tumor necrosis factor to solid tumors.Functionalized Particles have been extensively used to study cellular uptake of nanoparticles and targeted drug delivery