Studies of protein adsorption bovine serum albumin (BSA),
myoglobin (Mb), and cytochrome c (CytC)) onto self-assembled
monolayers of mercaptoundecanoic acid (MUA) on Au nanoparticles
using the quartz crystal microbalance (QCM) show that all three
proteins form adsorption layers consisting of an irreversibly adsorbed
fraction and a reversibly adsorbed fraction21. This corresponds very well
with the notion of a nanoparticle-protein corona, which is proposed
to have a hard corona composed of those proteins that have a strong
adsorption to the nanoparticles and a long residence time and a softer
corona composed of those proteins with shorter residence times and/or
lower affinities.