There is currently great excitement about the potential of nanomaterials for biomedical imaging and therapy, exploiting mesoscopic material properties unique to this size domain. To realize biological applications it is essential to develop stable aqueous-compatible materials and understand what happens to them when they are introduced into biological environments. When nanoparticles are introduced into blood or other biofluids, proteins adsorb on the surface forming a corona. The protein corona can be thought of as a biomolecular interface composed of a hard and a soft corona with long and short typical exchange times, respectively. This corona will be the biologically-relevant moiety interacting with the cellular machinery. Much effort has been directed to engineering nanoparticle surfaces to attach ligands for biological targeting (peptides, antibodies etc) and to alter pharmacokinetic profiles (PEG), but it is not at all clear what the biological system sees when such particles are used. For these reasons, we wish to investigate further the adsorption of protein coronas onto nanoparticles placed in blood serum using SANS as a function of different parameters.