Solid, liquid, gas, plasma: Of the four states of matter that exist in our universe, plasma comprises, by far, the largest portion. Here on earth, plasma can be witnessed in the glow of a fire, the excited mercury vapor in a flourescent lightbulb, or in the image from a plasma TV. Scientists have known about and worked with plasmas for decades, but recent breakthroughs working with cold plasmas opened the gates to a world of technology straight out of science fiction.The potential use of plasmas is in their generation of free electrons. These electrons can be used to disinfect, or disable biological contaminants, to etch metal, to construct electronic circuits, or make cuts in skin. Hot plasmas are already in use for some of these purposes, used to weld metal, etch computer chips and break down byproduct chemicals from manufacturing processes. Cold plasmas are called “cold” because they can be created in room temperature environments at atmospheric pressure. Since the plasma is a much lower temperature, it naturally requires less energy to produce, and is much more feasible for inclusion in more commonplace technology. Even so, cold plasma might not be so cold by everyones standards, some exceeding 212?F in temperature, but compared to the hot plasma of particles that composes our sun, 212? might not be much to complain about.
At the forefront of cold plasma research is Dr. Mounir Laroussi, director of the Laser and Plasma Engineering Institute at Old Dominion University in Virginia. Laroussi has developed a “plasma pencil”: a handheld device which produces a small two inch plume of helium plasma at one end. The effective heat dissipation of the helium keeps the plasma cool and stable, allowing its application to sensitive surfaces such as skin. Although the pencil won’t destroy mammalian skin cells, it has been shown to effectively kill E. coli and salmonella, among other harmful bacteria. The plasma pencil could provide a safe new medical technology for easily disinfecting wounds, and in the future could be developed to remove plaque, or kill cancerous skin cells.
Other advances in medical technology have been made as well. In the Netherlands, Eva Stoffels-Adamowicz of Eindhoven University of Technology has developed a similar device, a plasma needle with a nitric oxide plasma plume, much shorter and finer than that of Laroussi’s pencil. The human body produces nitric oxide to fight infection and reduce swelling, and so the plasma needle can be used to hasten such processes, as well as to manipulate small amounts of cells with very precisely. Peak Surgical, in Palo Alto, California, is researching a “bloodless scalpel” that can cut through skin and flesh. Unlike a metal scalpel, the cold plasma device activates platelets, causing the blood to clot and reducing bleeding significantly. The new tool is also an advantage over electrosurgical devices which cauterize as they cut, because it does not burn the surrounding healthy tissue.
The realm of medicine is not the only place where cold plasma has been utilized in new technology. Plasmas can also provide radar cover for airborne devices such as satellites, acting like a rudimentary cloaking force field. A large sealed box filled with an inexpensively produced cold plasma could disarm biological agents such as anthrax. Whether in medicine or military technology, scientists have barely touched the possibilities for cold plasma technology.
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