Within the medical device community, it is now well accepted
that material surfaces are modified by the adsorption of biomolecules
such as proteins in a biological environment1–10, and there is some
consensus that cellular responses to materials in a biological medium
reflect the adsorbed biomolecule layer, rather than the material
itself1,3,6. An early study in the field of protein interactions with planar
surfaces drew attention to the fact that distortion of the protein may
occur upon adsorption11. However, the importance of the adsorbed
protein layer in mediating interactions with living systems has been
slower to emerge in the case of nanoparticle-protein interactions.
While studies of protein adsorption to nanoparticles are beginning to
appear12–14, the importance of the detailed structure of the adsorbed
protein-solution interface (the outer surface of the adsorbed protein
layer taking into account any changes in protein structure) has not yet
been widely appreciated in the nanotoxicology literature1,15,16, despite
the fact that this is the primary surface in contact with cells.