Copper(II)-MOF Containing Glutarate and 4,4′-Azopyridine and Its Antifungal Activity

Abstract

Antifungal activities of MOFs (metal organic frameworks) have been demonstrated in studies, and improvement in efficiency of fungal inactivation is a critical issue in the application of MOFs. In this study, we employed 4,4′-azopyridine (AZPY) in the construction of MOF to improve its antifungal activity. Three-dimensional (3D) copper metal organic framework containing glutarate (Glu) and AZPY (Cu(AZPY)-MOF) was synthesized by a solvothermal reaction. Glutarates bridge Cu2 dinuclear units to form two-dimensional (2D) layers, and these layers are connected by AZPY to form a 3D framework. When spores of two fungi, Candida albicans and Aspergillus niger, were treated with Cu(AZPY)-MOF for one day, number of CFU (colony forming unit) was continuously reduced over treated MOF concentrations, and maximum 2.3 and 2.5 log10CFU reductions (approximately 99% reduction) were observed in C. albicans and A. niger, respectively. Small amounts of CuII ions and AZPY released from Cu(AZPY)-MOF were not critical for fungal inactivation. Our results indicate that the level of antifungal activity of Cu(AZPY)-MOF is greater than that of Cu-MOF without AZPY constructed in our previous study, and intercalation of AZPY is able to improve the antifungal activity of Cu(AZPY)-MOF.

Keywords

• 4,4′-azopyridine
• glutaric acid
• metal-organic frameworks (MOFs)
• X-ray crystallography
• antifungal activity