Fig. 3. A) Schematic illustration of the preparation of Fe₃O₄@PAA/AuNCs/ZIF-8 for simultaneous tri-modal cancer imaging and chemotherapy. B) DOX release curve of Fe₃O₄@PAA/AuNCs/ZIF-8 at pH 5.3 and 7.4, and in vitro cytotoxicity results of Fe₃O₄@PAA/AuNCs/ZIF-8 NPs, DOX-loaded Fe₃O₄@PAA/AuNCs/ZIF-8 NPs and free DOX against HepG-2 cells at different concentrations. C) Schematic illustration of the preparation of AP-ZIF-90@DOX. D) SEM and TEM images of AP-ZIF-90@DOX. E) DOX release profiles of AP-ZIF-90@DOX at different pH values and ATP concentrations. Reprinted with permission. Copyright RSC, 2015 and Elsevier, 2019.