Ag-doped magnetic metal organic framework as a novel nanostructured material for highly efficient antibacterial activity

Abstract

In the last decades, numerous attempts have been made to prevent microbial pollution spreading, using antibacterial agents. Zeolitic imidazolate framework-8 (ZIF-8) belongs to a subgroup of metal organic frameworks (MOFs) merits of attention due to the zinc ion clusters and its effective antibacterial activity. In this work, Ag-doped magnetic microporous γ-Fe₂O₃@SiO₂@ZIF-8-Ag (FSZ-Ag) was successfully synthesized by a facile methodology in room temperature and used as an antibacterial agent against the growth of the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria. Several characterization methods were applied to analyze the properties of the materials, and the results confirmed the accuracy of the synthesis procedure. Silver ions have employed to enhance the efficiency of antibacterial activity. As the results illustrated, FSZ-Ag nanostructured material had superior performance to inactive E. coli and S. aureus in growth inhibition test in liquid media. The best antibacterial activity as minimum inhibitory concentration (MIC) was 100 mg/L of FSZ-Ag against both bacteria. Leaching rates of silver ions showed that 80% of Ag released in the solutions, which was responsible for inhibiting the growth of bacteria. Also, fluorescence microscopy was used to investigate bacterial viability after 20 h contacting FSZ-Ag to distinguish live and dead bacteria by staining with DAPI and PI fluorescence stains. This novel magnetic nanostructured material is an excellent promising candidate to use in biological applications as high potential bactericidal materials.

Keywords: Antibacterial activity; Magnetic nanostructured material; Metal organic framework; Silver doping; ZIF-8.