Journal Article

Copper and Zinc Metal–Organic Frameworks with Bipyrazole Linkers Display Strong Antibacterial Activity against Both Gram+ and Gram− Bacterial Strains

Marchetti, Fabio, Pettinari, Riccardo, Olivieri, Laura, Tombesi, Alessia, Pettinari, Claudio, Xhafa, Sonila, Di Nicola, Corrado

2023

Overview

Here, we report a new synthetic protocol based on microwave-assisted synthesis (MAS) for the preparation of higher yields of zinc and copper in MOFs based on different bis(pyrazolyl)-tagged ligands ([M(BPZ)]n where M = Zn(II), Cu(II), H2BPZ = 4,4′-bipyrazole, [M(BPZ-NH2)]n where M = Zn(II), Cu(II); H2BPZ-NH2 = 3-amino-4,4′-bipyrazole, and [Mx(Me4BPZPh)] where M = Zn(II), x = 1; Cu(II), x = 2; H2Me4BPZPh = bis-4′-(3′,5′-dimethyl)-pyrazolylbenzene) and, for the first time, a detailed study of their antibacterial activity, tested against Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, as representative agents of infections. The results show that all MOFs exert a broad-spectrum activity and strong efficiency in bacterial growth inhibition, with a mechanism of action based on the surface contact of MOF particles with bacterial cells through the so-called “chelation effect” and reactive oxygen species (ROS) generation, without a significant release of Zn(II) and Cu(II) ions. In addition, morphological changes were elucidated by using a scanning electron microscope (SEM) and bacterial cell damage was further confirmed by a confocal laser scanning microscopy (CLSM) test.

• Publisher: MDPI AG,MDPI
• Subject: antibacterial activity / Antibacterial agents / Antimicrobial agents / Bacteria / bis(pyrazolate) ligands / chelation theory / Composite materials / Cu(II) and Zn(II) MOFs / E coli / Escherichia coli / Health aspects / Investigations / Ligands / Morphology / Reactive oxygen species / ROS generation / Staphylococcus aureus / Staphylococcus aureus infections / Zinc