Scientists develop bacteria killing "plasma pencil"

Nature.com reports that scientists at the Old Dominion University in Norfolk,
Virginia, have developed a "plasma pencil" that can be used to kill bacteria without damaging surrounding tissue. The device, which is only about 12-centimeteres long, works by passing a stream of helium gas containing a trace of oxygen between two high-voltage copper electrodes, which breaks the oxygen molecules into two highly reactive oxygen atoms that then attack the bacteria.  Experiments have shown that the plasma beam can kill Escherichia coli bacteria with no effect on the skin and the researchers believe it can also be used to clean up plaque-generating bugs and potentially even tumor cells.