Zn-MOFs incorporating 1,2-bis(4-pyridyl)ethylene and 4,4′-azopyridine: Unlocking new frontiers in antifungal research

Abstract

Metal–organic frameworks (MOFs) have gained significant attention for their antimicrobial properties due to their structural versatility and functional tunability. In this study, two Zn-MOFs, namely, 1-bpe and 2-AZPY, were synthesized using bpe and AZPY ligands, respectively, via solvothermal reactions. These MOFs were systematically evaluated for their antifungal activities against C. cladosporioides, A. niger, and C. albicans. Structural characterization confirmed both MOFs as two-fold interpenetrated frameworks with thermal stability up to 300 °C. Antifungal tests demonstrated that 2-AZPY exhibited superior antifungal efficacy compared to 1-bpe. At a concentration of 2 mg/mL, 2-AZPY achieved 95% inactivation of A. niger and 61% inactivation of C. cladosporioides, while 1-bpe showed relatively weaker antifungal performance. The enhanced antifungal activity of 2-AZPY is attributed to the release of AZPY ligands, which promote thiol oxidation in fungal proteins, leading to cellular inactivation. Further improvement was achieved by incorporating 2-AZPY into a polyvinyl alcohol (PVA) nanofiber matrix, forming 2-AZPY@PVA. This composite significantly enhanced antifungal performance, achieving nearly complete inactivation of all tested fungal species. These findings underscore the potential of AZPY-functionalized MOFs for targeted antifungal applications, particularly when integrated into nanofiber materials for enhanced bioavailability and stability. The results highlight the promising role of MOFs in developing effective antifungal agents for environmental and medical applications.