Fabrication of Silver-Doped UiO-66-NH2 and Characterization of Antibacterial Materials

Abstract

Metal-organic frameworks (MOFs) are highly crystalline inorganic-organic complexes formed from metal ions or metal clusters and multi-toothed organic ligands. MOFs have great potential for use in antibacterial materials in the biological, environmental, and food antimicrobial fields. They can act as a reservoir of metal ions, releasing them gradually and leading to a sustained antibacterial effect analogous to that proposed for metal oxide nanoparticles (NPs). Herein, UiO-66-NH2 as a type of MOF was first prepared by a facile solvothermal method and then loaded with Ag NPs to form a Ag/UiO-66-NH2 composite and the different materials were synthesized by controlling silver doping amount, which are then applied to an antibacterial test. Works on the synthesis of Ag/UiO-66-NH2 and its antibacterial test were not reported before. The synthesized materials were characterized using the field emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) techniques. The antibacterial activity of the Ag/UiO-66-NH2 was then assessed against E. coli (gram-negative bacteria) and Staphylococcus aureus (gram-positive bacteria), using the inhibition zone (ZIO) method and optical density (OD) method. The obtained results have shown that the introduction of Ag does not interfere with the crystallization of UiO-66-NH2. The FT-IR spectral profiles recorded for the UiO-66-NH2 samples fabricated under conditions of varying silver ion doping levels are similar to those recorded for UiO-66-NH2. The thermal stability of UiO-66-NH2 containing varying amounts of silver ions was lower than the thermal stability of UiO-66-NH2. However, under these conditions, the specific surface area and pore volume increased. The antibacterial performance of UiO-66-NH2 improved significantly following the process of silver ion doping. The best antibacterial performance was observed when the silver ion content was 4 wt.%. Overall, we synthesized a new nanocomposite material with broad-spectrum bacterial sterilization, which was easy to manufacture.