DIY Plasma pencil?

Janet sent this in and has issued a Maker challenge to build a “Plasma Pencil” – “The pencil generates a “cold plasma,” which can be used to kill germs that contaminate surfaces, infect wounds and rot your teeth. In the future, it might be used to destroy tumors without damaging surrounding tissue. Laroussi, an associate professor at Old Dominion University, hopes the beam will soon find its way into doctors’ and dentists’ offices.” Link.