None — What is Plasma?
In basic science, children are taught there are three states of matter – solid, liquid and gas. Plasma is now described as the fourth state of matter. It's formed when energy is applied to a gas, freeing some electrons from the gas atoms. This process creates positively charged atoms (called ions) and negatively charged electrons, forming an ionized gas.
Plasma is abundant around us. It makes up 99 percent of everything we can see. The sun, stars, lighting and the auroras are natural examples of plasma. Scientists have learned how to harness plasma to produce many items used by consumers and industry, like flat screen plasma televisions, fluorescent lights, arc welding machines, computer chips and material coatings.
Medical Uses of Plasma
There are two types of plasma, thermal and non-thermal. Greg Fridman, Ph.D., Biomedical Engineer with the Drexel Plasma Institute in Philadelphia, PA, says thermal plasmas are generally 10,000 degrees and hotter. In medicine, thermal plasma devices are used to cut and destroy tissue and coagulate blood vessels (i.e., stop bleeding). Non-thermal plasmas are much cooler. One type of non-thermal plasma that has significant medical implications is cold plasma, which remains close to room temperature. The lower temperature of cold plasma allows it to be used without damaging surfaces or healthy tissue.
Researchers at the Drexel Plasma Institute pioneered the use of cold plasma for medicine. One potential use of cold plasma is in the area of decontamination. Cold plasma produces reactive oxygen species, which damages bacterial DNA and often causes the cell walls to rupture, killing the cell. Fridman says human cells appear to be protected from this process because our cells contain cholesterol and bacteria do not. According to the Coalition for Plasma Science, high concentrations of bacteria can be destroyed after just ten seconds of plasma exposure. The process works even for some of the most resistant strains of bacteria, like MRSA. It's also effective in fighting some types of fungal diseases and prion disease (i.e., Mad Cow Disease).
Alexander Fridman, Ph.D., Director of the Drexel Plasma Institute, says cold plasma technology can be used to decontaminate surgery sites and help ulcers and chronic wounds heal. Special endoscopes and other medical instruments can deliver the treatment to sites inside the body (like the digestive tract) to heal conditions such as Crohn's disease and colitis. There is even some evidence (in mice) the technology may effectively destroy brain cancer without risk to healthy brain cells.
Cold plasma can also be used to decontaminate surfaces, like medical equipment and hospital rooms. It can completely sterilize the entire surface of the hand, reducing the risk of spread of germs in the hospital (some areas may be missed using traditional hand cleaning techniques). On the battlefield, cold plasma could be used to clean combat wounds, sterilize equipment and decontaminate makeshift field hospitals. Researchers say cold plasma may also be a very effective method of decontamination after a biological attack because plasmas can break down nerve and biological toxins within minutes.
Another use of cold plasma is in coagulation of blood vessels. Unlike thermal plasma, which seals by heat and can damage healthy tissue, cold plasma can stop bleeding without damaging healthy tissues. Researchers are also studying cold plasma for removal of periodontal disease and several types of skin diseases.
For information on the plasma research program at Drexel University, click here.
General information is available from The Coalition for Plasma Science.