Tuning the unsaturated iron sites in MIL-101(Fe) nanoparticles for reactive oxygen species-mediated bacterial inactivation in the dark

In this study, reactive oxygen species (ROS)-mediated antibacterial activity with high efficiency in the dark was achieved by modulating the active sites of MIL-101(Fe) nanoparticles. The ROS production over x-MIL-101(Fe) nanoparticles was intensively enhanced by tuning the unsaturated iron sites (FeII/FeIII, the ratio was marked as x %). Electron paramagnetic resonance (EPR) analysis confirmedmore ROS generation on x-MIL-101(Fe) surface than that on MIL-101(Fe), due to more electrons shifting from benzene rings to FeII/FeIII sites. Among all samples, 8.9-MIL-101(Fe) displayed the highest inactivation efficiency (> 99.99%) against Escherichia coli within 2 h in the dark. ROS reacted with cell wall components to generate carbon-centered radicals via H abstraction, leading to the disruption of cell wall, intracellular ROS, and DNA damage. Antibacterial performance of 8.9-MIL101(Fe) in air filters indicated 8.9-MIL-101(Fe) can be applied to prevent the spread of airborne pathogens. The results are promising for the ambient antibacterial application of MOF materials.

Automated summary

By modulating the active sites of MIL-101(Fe) nanoparticles, efficient ROS-mediated antibacterial activity in the dark was achieved. 8.9-MIL-101(Fe) displayed the highest inactivation efficiency against Escherichia coli in the dark and can effectively prevent the spread of pathogens in air filters.