Figure 2.

A hard versus soft protein corona model on the surface of nanomaterials in the biological milieu. Hard corona is analytically accessible by the NP–protein complex which is adsorbed primarily when NPs are in contact with a biological medium. It is tightly bound due to a high degree of affinity and isdesorbed easily. In contrast, soft corona is loosely bound and rapidly exchangesbiomolecules. The term protein corona/biomolecule corona is exchangeable with hard corona or analytically accessible corona.