Reidy Center Researchers Granted U.S. Patent for their Cold Plasma Research

Two Old Dominion University faculty members and a former doctoral researcher at the Frank Reidy Research Center for Bioelectrics have been granted a U.S. patent based on their novel use of gases to create a jet of atmospheric plasma - something that could have many applications, especially in medicine.

The patent, "Method and Device for Creating a Microplasma Jet," was granted in August to Juergen Kolb, assistant professor of electrical and computer engineering; Karl Schoenbach, eminent scholar and Batten Endowed Chair in Bioelectric Engineering; and Abdel-Aleam Mohamed, one of Schoenbach's former doctoral students.

Known as the "fourth state of matter," plasma is being investigated for a number of uses, especially the so called "cold" plasmas that can be safely and affordably emitted into the atmosphere in a controlled fashion.

The ODU team's concept involves a high-voltage device, possibly battery driven, that ionizes plain air. The resulting plasma is shot in a jet-like plume out of a device the size of a small power tool. Its temperature is about room temperature or slightly above. One use of this plasma plume would be to disinfect wounds. First results of studies, related to fungal infections are encouraging.

Schoenbach has been working in the emerging field of high pressure microplasmas for more than a decade. A paper his group published, now highly cited, introduced a discharge of plasma under high pressure, a concept scientifically known as microhollow cathode discharges.

By 2003, Schoenbach said, this new area of study had already stimulated enough interest to establish a worldwide conference on microdischarges in Kyoto, Japan.

"Our plasma jet, which is based on the original concept published in 1996, is one of the examples of how far this area of research has come," Schoenbach said.

Kolb said plasmas are typically associated with high temperatures and must be operated under reduced pressures. "With this generation of cold atmospheric pressure plasmas, it is now possible to harness processes inherent to this fourth state of matter, which were not yet available," he said.

The patent was first applied for in 2005, but Kolb said efforts on the project since have taken the research in two, complementary directions.

The first involves technology - the development of a device that emits the plasma beam in a user-friendly manner. "We believe we can make the whole setup (power supply, air feed) much smaller while we can, at the same time, increase the size of the plasma plume," Kolb said.

Kolb said that their device operates with a simple DC electric current and on air -- are appealing advantages for many applications. That inspired the team to continue making improvements on the device in the four and a half years since applying for the patent.

"Eventually, I hope we can offer an almost maintenance-free system, about the size of a shoebox, that every physician would like and could afford to have in his office for quick treatments to minimize the risk of infections on skin and, in particular, on wounds," Kolb said, adding that this idea has already piqued the interest of the U.S. Army.

That flows into the researchers' second goal - better understanding the interaction mechanisms of plasma with biological matter, such as cells and tissue. Could the researchers end up finding a way to treat a pathogen that causes infection or disease? Testing and research is the only way to find out.

"We want to test the efficacy of our plasma empirically against a vast variety of pathogens with different characteristics," Kolb said. "There is still a lot of research that needs to be done in order to understand and improve the technology."

Ultimately, Kolb believes that other medical applications for the technology will be found by the ODU group and other researchers worldwide.

"However, since a variety of other cold plasma applications have emerged over the last decade, I would not be surprised to also see the technology being introduced and used in areas that we cannot imagine yet," he said. "Who would have thought that lasers would be used as pointing devices, for playing music, removing facial hair and cutting metal?"