A Personal View of Plasma Medicine

Plasma Processes and Polymers has just published its second special issue devoted to Plasma Medicine (Vol. 7, No. 3-4, March 2010). Prof. Mounir Laroussi from Old Dominion University in Virginia, USA, is one of the guest editors, and he shares with us some of his insights.

MV: As a pioneer in the field of plasma medicine you clearly find the topic exciting. Can you share with our readers your views on why it is so special?

ML: Historically, engineering-based solutions/technologies have always been used to solve healthcare problems. For example, fire was used for hundreds of years to coagulate blood and help in wound healing. Then cleverly engineered tools were developed for surgery etc... In modern times, lasers and advanced imaging techniques are playing great roles in medicine. Today, we are trying to take advantage of the fourth state of matter, plasma, to continue the quest to use clever engineering solutions to overcome tough medical challenges.

MV: What is your own involvement in plasma medicine research?

ML: It was 1994 when I first had the idea to apply cold atmospheric pressure plasma to kill bacteria. The experiment was successful and I published my results in 1996 in the IEEE Transactions on Plasma Science (see photo of "Plasma Pencil"). Today, my research has expanded greatly to include dental applications, interaction of plasmas with eukaryotic cells (like mammalian cells), destruction of proteins (some of these cause neurodegenerative diseases), etc...

MV: How have you seen the field develop?

ML: In 1998 I chaired the first conference oral session that dealt with the biological applications of plasma. Only few people were involved in this kind of research at that time (mostly in the US). However, since the early 2000s many research groups got interested in this new application of plasma, and the community kept growing ever since. Since 2002 or so, almost every major plasma conference has a session on the biomedical applications of plasmas and starting the last few years, workshops and mini-conferences dedicated to plasma medicine have sprung up. I am delighted about all these developments.

MV: Now, for those of us who don't know; what is plasma?

ML: Plasma, the fourth state of matter, is a collection of charged particles (electrons and ions), neutral atoms and molecules, radicals. When heated enough or subjected to high electrical stress, a gas turns into a plasma. Unlike a neutral gas, plasma responds to electrical and magnetic fields.

MV: Plasma sounds as thought it could be dangerous; how is it made safe for medical applications?

ML: The plasma devices that we use for medical applications generate low temperature plasmas (below 40 degrees Celsius). Ideally they should not generate UV radiation, the kind that damages DNA. These plasmas have to be also safe electrically.

MV: How is plasma used in a medical context?

ML: Plasmas were found to kill bacteria, help coagulate blood, enhance to proliferation of fibroblasts, induce apoptosis (programmed cell death). Therefore plasma can be used in sterilization of tools and equipment, assist in wound healing, destroy some types of cancer cells, etc….

MV: What is it about plasma that allows it to do these things?

ML: Plasmas generate reactive species and radicals, such as atomic oxygen, hydroxyl, nitric oxide (NO), superoxides, etc... It is these short lived chemical species that play a major role in the plasma interaction with biological cells. In addition, plasmas have charged particles (electrons and ions). Many scientists think they also play a role in initiating reaction at the surface of the cells.

MV: Is plasma being used in medical treatment now, or is it still at the research and development stage?

ML: For most of the medical applications, plasma is still in the research stage.

MV: What needs to be done before plasma medicine becomes a part of our healthcare?

ML: First there has to be extensive animal studies to verify that plasma is not cytotoxic and to determine under what optimum operating conditions can plasma induce desirable effects (i.e, kill cancer cells, proliferate fibroblasts, etc….)

MV: You listed many applications above; what is most likely to be the first widespread realization of plasma medicine?

ML: Sterilization of tools, skin, gear and equipment may be the first achievable uses of plasmas.

MV: What are the major challenges currently facing (researchers in) plasma medicine?

ML: Destruction of pathogenic proteins, such as prions, and the destruction of biofilms are two of the challenges that come to mind.

MV: What inspired the special issue?

ML: The scientific community working on the biomedical applications of plasma is growing very fast in number. It is very desirable to publish reviews and new results between the covers of a single issue. This way, it is easier for investigators to retrieve the latest findings and developments in the field. This is the second time we do this in this journal. The first special issue was published in 2008.

MV: What are the highlights in the special issue, as you see them?

ML: The application of cold plasmas in wound care is an exciting prospect. Tens of thousands of amputations occur in the US alone every year because of chronic wounds (such diabetic ulcers). Gas plasma technology may be able to help reduce the need for these amputations. However, there are still many advances that need to happen before this goal is reached.

MV: A final word?

ML: I just hope that this new healthcare technology (Plasma Medicine) will soon bring some relief to the suffering of many patients and cure some diseases that were thought not curable. If that happens, it will feel so good.