Fig. 21

a Schematic of the mechanism of hard corona formation and catalysis inhibition before intra-endosomal reactivation. b Soft corona formation and enhancement of catalysis upon endosomal uptake. c Inhibition of endosomal uptake due to the presence of a zwitterionic headgroup on the nanozyme. d Nanozyme-mediated Rhodamine 110 uncaging. e Confocal imaging of the HeLa cells after 8 h of incubation with the nanozyme and pro-Rho, and a control group with a protease inhibitor. Endosomal proteolysis is crucial for restoring catalytic activity. f Schematic of the trypsin-mediated reactivation of nanozyme catalysis. g Quantification of the dye release of the hard corona nanozyme, the nanozyme after proteolysis, and the control with a protease inhibitor through fluorescence spectroscopy. Reprinted from Ref. [22] with permission from the American Chemical Society. Copyright 2020