Postsynthetic Modification of ZIF-90 for Potential Targeted Codelivery of Two Anticancer Drugs

Combination therapy has been regarded as a promising strategy for cancer treatment due to the enhanced anticancer efficacy achieved by blocking multiple drug resistance pathways. In this work, a drug carrier based on nanoscale ZIF-90 for the codelivery of two anticancer drugs has been synthesized by covalently attaching doxorubicin (DOX) to the surface of ZIF-90 via Schiff base reaction of amino group in DOX and aldehyde group of imidazole-2-carboxaldehyde (ICA) ligand and encapsulating 5-fluorouracil (5-FU) into the pores of the framework. The results of drug loading measurements show that the loading amount of drugs was estimated as high as 36.35 and 11–13.5 wt % for 5-FU and DOX, respectively. Moreover, we demonstrated that the carrier had the potential of cancer-targeted delivery of drugs for the collapse of framework under the pH environment around cancer cells and subsequently releasing drugs. Drug release at pH 5.5, imitating the environment of tumor, can reach over 95%, and the release time is less 16 h, meaning a more effective and faster release of drugs around tumoral cells than that in a normal environment. This is the first report for cancer-targeted codelivery of two different chemical drugs based on nanoscale metal–organic frameworks (NMOFs).