Fig. 4

Schematic illustration and characteristics of a hard and a soft corona. The protein corona encompassing the nanoparticles. Hard coronas are characterized by slow exchange (i.e., several hours) and lower abundance, with a high affinity of proteins, whereas soft coronas are typified by rapid exchange (i.e., several minutes) and lower affinity of proteins with weakly bound outer layers on nanoparticles. There is a different response of cellular and biochemical factors by soft and hard corona formation. *Compared with serum-free condition. ^†Compared with soft corona (modified from ref. Lee et al. [41])