Synthesis, characterization and antibacterial activity of imidazole-functionalized Ag/MIL-101(Cr)

Nowadays, nanomaterials have rapidly developed as a new generation of antibacterial agents. However, high local aggregation and concentration, and possible toxicity due to excess leaching are disadvantages of nanoparticles. Unique features of metal–organic frameworks (MOFs) such as coordinately unsaturated centers, high surface area and facile synthesis attracted attention to overcome the above-mentioned problems. In this context, Ag/MIL-101(Cr)/IMI was synthesized, and after characterization by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM–EDX), Transmission Electron Microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), inductively coupled plasma-optical emission spectrometry and BET surface area, TG–DTA was used as an antibacterial agent. Imidazole-functionalized Ag/MIL-101(Cr)/IMI presented a synergistic effect of imidazole and silver NPs against Escherichia coli (ATCC25292) and Staphylococcus aureus (ATCC25293) bacteria. The best antibacterial activity as minimum inhibitory concentration (MIC) was 6.2 µg/mL and 24.78 µg/mL of silver content against E. coli and S. aureus , respectively. There were 81 and 144.9 mg of Ag and imidazole per each gram of Ag/MIL-101(Cr)/IMI, which leaching rates of Ag, imidazole and Cr were 150, 828 and 153 µg/L, respectively. This leaching level of imidazole was lower than the amount recommended by Registry of Toxic Effects of Chemical Substances (RTECS) from NIOSH, while the leaching levels of silver NP and chromium is tended to be around the standard of WHO and U.S.EPA.