Gold nanoparticle encapsulated hybrid MOF: synthesis, characterization, and co-drug delivery of 5-fluorouracil and curcumin

The unique features of Metal-Organic Frameworks (MOFs), including structural flexibility, high surface area, and variable pore size, have drawn attention in cancer therapy. However, despite advances in surface functionalization, engineering structural features, and porosity, achieving controlled release, stability, scalability, and toxicity remains a challenge. The current study reports gold nanoparticle (AuNP) encapsulated dual metal-organic frameworks (MOFs) comprising zeolitic imidazolate (ZIF8) and cobalt-imidazole (ZIF67) by a simple precipitation method for dual drug delivery applications. This combination associates the advantages of AuNPs and MOFs, creating a potent platform for cancer theranostics that combines diagnosis and treatment into one unit. The synthesized composite (AuNPs@ZIF-8/ZIF-67) is functionalized with Folic acid (FA) and loaded with the anticancer agents Curcumin (C) and 5-fluorouracil (5-FU) for co-drug delivery The synthesized composites, namely Au/ZIF8, Au/ZIF8/ZIF67/FA, Au/ZIF8/ZIF67/FA/5-FU, and Au/ZIF8/ZIF67/FA/5-FU/C were characterized using diverse analytical techniques such as FESEM, XRD, FTIR, TEM, and BET. The characterization methods showed that the hybrid MOF structure was stable and intact after AuNP encapsulation and drug loading. The dual MOF composite exhibits a better affinity for loading C and 5-FU with 60% and 40% drug loading capacity, respectively. The simultaneous drug release studies suggest that AuNPs@ZIF-8/ZIF-67 are more responsive to the acidic pH and show a higher cumulative drug release of 5FU and C at the lower value of pH 5. For further validation, the release kinetics data were fitted into the Korsmeyer-Peppas model in the current study. The observed value of n which is less than 0.5 suggests the pseudo-Fickian diffusion mechanism for drug release, demonstrating long-term release of 5FU and C from Au/ZIF8/ZIF67/FA/5-FU/C. The targeted drug delivery system is anticipated to display synergistic therapeutic efficacy from the combined effect of the two anticancer agents and the pH-responsive nature of ZIF systems.