Interaction and diffusion of gold nanoparticles in bovine serum albumin solutions

We studied the interactions of small sized, radius of 2.5-10 nm, gold nanoparticles (AuNPs) with bovine serum albumin (BSA). Fluctuation correlation spectroscopy (FCS) was used to monitor the changes in the Brownian diffusion of these NPs. Our results indicate a BSA monolayer formation at the NP surface with a thickness of 3.8 nm. The thickness of the adsorbed layer was independent of NP size. Best fit was obtained by the anticooperative binding model with the Hill coefficient of n = 0.63. Dissociation constant (K-D) increases with particle size indicating stronger interaction of BSA with smaller sized NPs. (C) 2013 AIP Publishing LLC.