Derivative of Epigallocatechin-3-gallatea Encapsulated in ZIF-8 with Polyethylene Glycol–Folic Acid Modification for Target and pH-Responsive Drug Release in Anticancer Research

Epigallocatechin-3-gallatea (EGCG), a key component of tea, has been found to have anticancer activity but poor stability. To improve its antioxidative stability and widen the application of EGCG in anticancer therapy, a kind of EGCG derivative, EGCG palmitate (PEGCG), was synthesized and encapsulated in ZIF-8 nanoparticles with functionalization of folic acid (FA), which is commonly used as pH-responsive drug carrier. PEGCG encapsulated in polyethylene glycol (PEG)–FA/ZIF-8 nanoparticles (PEG–FA/PEGCG@ZIF-8 NPs) exhibits sixfold improvement of stability compared to that of free PEGCG. With target recognition between folic acid (FA) on the surface of NPs and overexpressed FA receptor (FR) in cancer cells, the NPs can be efficiently internalized into cells and present targeted effects of inhibition growth on HeLa cells (cancer cells) compared with HEK 293 cells (normal cells), consistent with the regulation of reactive oxygen species (ROS) level and the induction of autophagy. The detection of autophagy fl...