Synthesis and Comparative Study of ZIF8 and ZIF7 Metal-Organic Frameworks as Carrier for Controlled Release of Doxorubicin in Cancer Treatment

Metal-Organic Frameworks (MOFs) offer significant potential as effective drug carriers due to their porous architecture, diverse chemical makeup, and adaptable properties. Zeolitic Imidazolate Frameworks (ZIFs) are significant nanocarriers due to their excellent biocompatibility and structural integrity. the toxicity exhibited by most ZIFs restricts their use as biomedicine. This study encapsulates the widely used chemotherapy drug doxorubicin (DOX) within biocompatible ZIF-8 and ZIF-7 nanoparticles, to develop an intelligent drug delivery system sensitive to changes in PH levels. The crystalline ZIFs with loaded DOX were subjected to systematic characterization using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and UltraViolet-Visible (UV-Vis) spectroscopy. Additionally, BET studies confirmed that surface modification had negligible influence on the surface area and distribution of pore size. Furthermore, kinetic and isotherm investigations were carried out, and experiments were conducted to examine the drug release dependency on pH. The results revealed a remarkable pH-responsive release, with ZIF-8 demonstrating a cumulative amount of 80% at pH 5.5, starkly contrasting the negligible release observed at pH 7.4. This unique pH-responsive behavior was attributed to the regulated degradation of the ZIF-8 framework in an acidic environment typically found in tumor sites. On the other hand, ZIF-7 exhibited negligible pH-responsive drug release with a higher chemical stability. Toxicity tests conducted on MCF-7 breast cancer cells highlighted the enhanced effectiveness of DOX-loaded ZIF-8 in cancer therapy compared to DOX alone. Our findings demonstrate the significant potential of ZIF-8 as a custom nanocarrier for targeted and extended delivery of anticancer drugs, activated specifically by the acidic environment of tumors. These insights are vital for developing future MOF-based drug delivery systems tailored for cancer treatment.