from the protein sequences associated with the surface of nanoparticles. Unlike the situation for flat macroscopic surfaces say of medical implants, for nanoparticles the protein environment changes in different compartments of cells and organs, as the nanoparticle traffics. This has lent urgency to the modern interest in understanding the phenomenon at a more fundamental level [@Mono2011]. Still, we can learn a lot from an understanding of the process for flat surfaces [@Tengvall1998]. Studying the adsorption of Fibrinogen on a surface in contact with blood plasma, Vroman found that the surface concentration of Fibrinogen shows a maximum at an intermediate contact time, indicating that Fibrinogen is replaced with time by one or more families of different proteins [@VROMAN1962]. The phenomenon is not specific to Fibrinogen, but is a general effect for many other proteins [@Ortega1995; @Holmberg2009]. The plasma proteins compete for the occupation of the surface, resulting in a sequential competitive adsorption, known as the Vroman effect.

The effects depends on numerous factors such as the plasma dilution, the pH, the temperature, the surface charge and the specific surface chemistry [@Jackson2000]. In highly concentrated plasma, the sequential adsorption takes place in seconds, but it takes several minutes when the plasma is 