99 percent of the universe consists of plasma. Few people, however, have been able to get anything going with the term “plasma”. That could soon yet change, because plasma medicine is on the verge of becoming a new sharp, all-purpose weapon in medicine.
Medical plasma: Hot electrons, cold nucleus
In order to reach the fourth state of matter, a chemical element needs energy. If it, for example, strikes gas atoms or molecules in electromagnetic form, electrons are released from the atomic composite. The active mixture then consists of tiny charged particles, UV radiation, radicals, electric fields, and – normally – a high temperature.
If the gas however gets only so much energy that it makes the electrons independent and high temperatures are reached, the ionised atom or molecule does not resonate; “cold plasma” emerges. This is found in fluorescent lights or in the Aurora Borealis. Or in a plasma flame, which is no warmer than body temperature. For medicine, it thus offers not only the opportunity to sterilise devices, but also to disinfect wounds.
Plasma, it seems, can nonetheless do much more. It stimulates the tissue to renew itself and arms the immune system in the fight against unwanted matter in the body. This also includes cancer cells. And finally it eliminates the substance known as biofilm from teeth implants and prostheses. And the best part of all: so far, no resistance to the new microbe killer is known, while antibiotics and other disinfectants lose their strength with time.
Healing with radicals?
Greifswald in Mecklenburg-Western Pomerania is on the way to becoming one of the great centres of plasma research on humans. This is the home of the Leibniz Institute for Plasma Science and Technology (INP), here the neighbouring university has established the world’s first Chair of plasma medicine. Armed with more than five million euros, from 2011 to 2013 the German Federal Ministry of Research is promoting the campus PlasmaMed, where the INP is significantly involved. It is basic research in particular which is at home in Greifswald. Physicists together with physicians, pharmacists and other life scientists test the effect of cold plasma in the eyes of freshly slaughtered pigs and on skin samples for wound healing and observe the stimulation of angiogenesis, i,e. the formation of new blood vessels. So far, when using an appropriate dosage no damage to the skin has been observed – despite almost complete disinfection.
On chronic wounds in dogs as well, “Tissue Tolerable Plasma” (TTP) has already brought about healing where all other strategies have failed so far. “A lot of evidence points to the idea that the active components in the plasma, in addition to the electromagnetic radiation, are those which are reactive types, that is to say radicals”, Thomas von Woedtke says, in an effort to explain the mechanisms. “Our hypothesis is that the radicals in the plasma support the endogenous radical-mediated defences and healing mechanisms of tissue and drive the formation of cell mediators such as nitric oxide”, according to the man who is first Chair of Plasma Medicine.
Two minutes for one third less bacteria
In other parts of Germany however, physics and medicine are cooperating closely on the development of new opportunities which are being brought by plasma. The Max Planck Institute for Extraterrestrial Physics in Garching, the Dermatology Clinic in Regensburg and the Municipal Hospital of Munich-Schwabing have introduced plasma medicine to the clinic. A Phase II clinical trial treatment using argon plasma has already been succesfully passed. Two minutes of treatment suffices with chronically infected wounds in order to reduce the bacterial colonisation of the wound by 30-40% employing about 100 applications. Georg Isbary of the Schwabing Hospital has meanwhile been successfully working on the skin of about 200 patients. Soon other dermatological conditions such as itching are to be put to the plasma test. In Göttingen a study on the treatment of open leg ulcers has just come to an end. A reduction of fifty percent with foot pain and wound healing in diabetic patients as compared with the control group was already able to be reported at a congress by a Russian working group in 2009.
Using the plasma pin for better teeth
At only about pen size, the device is used by dentists for taking the “energy clouds” into hidden holes, in order to put an end to dreaded biofilms. A plasma source such as kINPenMed helps in producing better ingrowth of implants but also in the treatment of drilled root canals. With periodontitis therapy plasma enhances wettability of the teeth and thus facilitates cleaning.
The use of plasma against cancer is still largely in the pre-clinical stage. Melanoma cells commit programmed suicide with the appropriate plasma dosage within 72 hours, while healthy tissue cannot be affected. Keratoses, scars, and even the influence on coagulation are further potential targets for plasma researchers in the coming years because plasma has the apparently irresistible charm of being used at doses which produce hardly any unwanted side effects. With a one-minute plasma treatment the UV-C dose is no higher than five minutes of sunbathing. Allergies? Not as yet known.
Conquests just like laser technology
Plasma medicine has only just made the leap from basic research into the clinic. There have therefore been few long-term observations on the effect of inert gas or “plasma air” in and on humans. However, as long as safety issues have not been made sufficiently clear, the treatment will probably not appear in the guidelines. Nonetheless the results so far already look very promising. Getting started is not exactly cheap: a device such as that which the doctors have been using in the Munich study for the time being demands an investment in the five-to six-figure range. Instruments for outpatient treatment are still in the thousands. The objective coming out of promotion of the campus PlasmaMed is that after 2013 a kick off in industrial development and manufacturing be set off. With mass production, the costs are then expected to decline.
And so the plasma researchers hope to tread a path similar to the laser, which has become an important tool in the hands of the physician. The Director of the Leibniz Institute for Plasma Science in Greifswald, Klaus-Dieter Weltmann, reckons on an equally bright future for the treatment of chronic wounds: “For some patients, plasma medicine might be the only alternative”.