Towards Standards for Light Scattering Studies of Proteins Stability and Nanoparticle-Protein Interactions

Protein-nanoparticle suspensions are nowadays widely studied for the development of medical and environmental biosensors. The complexity of interactions between nanoparticles and biological fluids, together with the increasing use of dynamic light scattering (DLS) for their characterization, support the need to develop common standards for DLS measurements and analysis, in order to enable a reliable comparison of measurement results. In this study, we use 3D cross-correlation Dynamic Light Scattering (3Dcc-DLS) for the characterization of gold nanoparticles (Au NP), with spherical and rod shape, stabilized with sodium citrate, and their interaction with bovine serum albumin (BSA). We show that for Au nanorods it is possible to distinguish the rotational and translational motion. Moreover, we monitor the interaction of Au NPs and BSA over time, in order to analyse the first step of protein corona formation. Our results show that Au nanorods interact more than Au nanospheres with BSA. From the evolution of the rotational and translational peaks we conclude that the proteins tend to bind on the long cylindrical side of the nanorods.