1. Solid, liquid and gas are what is generally called the three states of matter. Plasma is an ionized
gas, where ionization is obtained by applying energy to the gas, and it is the fourth state of
matter. Plasma is actually the most abundant state of matter in the universe, and examples of
plasmas are the aurora borealis, lightning, and the sun. These examples of plasmas have high
gas temperatures. Plasmas used in medicine are usually called cold plasmas, and have lower
gas temperatures that are suitable for treatment of living tissue without, or with minimal,
damage to surrounding healthy tissue.
The field of cold plasma in medicine is growing quickly and the possibilities seem endless. For
example, cold plasma has been shown to promote wound sterilization, blood coagulation, and
cell proliferation in wound healing.
In our project, a collaborative project of the Department of Physics and the Department of
Biology and Biological Engineering at Chalmers, we test the efficacy of cold plasma on
bacterial biofilms. In bacterial biofilms, bacteria have arranged themselves in a three
dimensional structure on surfaces, leading to colonization and infection. Because of how
closely cells in biofilms interact with each other, biofilms are very difficult to treat. Over the
past decades, infectious bacterial diseases have successfully been controlled with antibiotics.
However, the overuse, and inappropriate use, of antibiotics has caused bacteria to develop
antibiotic resistance, making bacterial infections an emerging threat again. The world is said to
be going into a post-antibiotics era and the antibiotic resistance has become a global threat
according to the WHO (World Health Organization). Thus, in addition to manage the usage of
antibiotics, there is a great need for novel approaches for treatment of bacterial infections.
We have already obtained good results where about, and over, 90% of the bacterial cells in the
biofilms have been eliminated by cold plasma exposure. Now we are also testing for the
synergistic effect of other antimicrobial agents with cold plasma, with the goal of increasing
the number of eliminated cells in the biofilms and decreasing the treatment time.