This paper reviews dynamic light scattering (DLS) of gold nanoparticle-protein interactions for the model protein bovine serum albumin (BSA), as well as in complex biofluids, at the example of mouse serum. DLS data of nanorods of various aspect ratio, of proteins and of mouse serum are discussed in terms of the analysis of their hydrodynamic radii, leading to the distinction of rotational and translational motion as well as to the detection of agglomerates. We address in particular advances obtained by modulated 3D cross correlation dynamic light scattering and recent progress using the CORENN algorithm for analysis of DLS data.