Light Releases Antibacterial NO

A porous material hosting a manganese complex that releases nitric oxide upon exposure to light could be used to kill antibiotic-resistant bacteria in wounds (J. Am. Chem. Soc., DOI: 10.1021/ja3022736). Nitric oxide can destroy bacteria via a number of routes—for example, by oxidizing cellular DNA or lipids in the cellular membrane. These multiple pathways should prevent microbes from becoming resistant to NO-based treatments. Researchers have been exploring strategies to administer NO as an antibacterial; as a gas, the molecule has been difficult to control. Pradip K. Mascharak and colleagues at the University of California, Santa Cruz, have now harnessed a photoactive manganese nitrosyl complex developed in their lab by packing the compound inside a meso­porous aluminosilicate material. They tested the resulting powder’s bactericidal powers on an agar gel “wound” impregnated with the pernicious drug-resistant bacterium Acinetobacter baumannii. This microbe has been nicknamed “Iraqibacter” after outbreaks of infections occurred in soldiers wounded in Iraq. When exposed to visible light equivalent to that emitted on a sunny day (about 100 mW/cm²), the material rapidly releases NO, which eradicates the bacteria.