ул. А.Невского, д.14
A research group of the Laboratory of Optical Radiation of the Immanuel Kant Baltic Federal University (IKBFU), a participant of the 5-top-100 Project, has suggested an efficient method for obtaining a stream of low-temperature plasma at atmospheric pressure. This technology can be used to treat various diseases caused by antibiotic-resistant bacteria. The research was presented at the International Symposium on “Physics, Engineering and Technologies for Bio-Medicine”.
Bacteria and parasites that cause a number of human diseases, including fatal ones, become more resistant to drugs and vaccines each year. That is why there is a need for new drug-less treatment methods.
One of such methods includes the usage of low-temperature plasma. Plasma is an ionized gas consisting of positive ions and free electrons. In nature, plasma is generated when lightning strikes and its charge with high current intensity passes through the air. In a lab, plasma can be obtained by passing electric current through a gas. To do so, two electrodes are connected to a source of electrical energy with high voltage. When the electrodes are connected to each other, the electric circuit closes, and the electric current passes through it. When the electrodes are separated, the electric current flows through the air and creates a charge in the gas. Gas is ionized and turned into plasma while passing through the electric current curve.
It is extremely important to control the gas temperature in plasma for medical usage. It should never be higher than 42°С (the level at which blood proteins start to coagulate). Moreover, the dosage of treatment should also be taken into account. Small amounts of ionized gas sterilizes the tissues and improves blood coagulation. When the dose increases, tumor cells die first and regular cells go after them.
The temperature of plasma depends to a great extent on the method of its obtaining and on the gas itself. When plasma is too hot it cannot be used for medical purposes. However, there is low-temperature plasma that heats up to less than 40°С, and the IKBFU researchers have developed a method for obtaining it and for using it in cancer treatment.
A research group of the Laboratory of Optical Radiation (IKBFU) has designed a device that generates a low-temperature plasma stream. The scientists used helium, which is one of the lightest and safest gases. In order to ionize it, they applied short high-voltage impulses to the passing electric current the way it does not heat the gas up to high temperatures. The researchers have carried out a number of experiments, so they determined the optimal speed for the helium plasma jet and the appropriate mode for the electric arc equipment. The reduction of gas consumption leads to the growth of plasma temperature but a short current impulse doesn’t heat the stream much too much.
Dmitry Schitz, a co-author of the study, head of the Laboratory of Optical Radiation at the FABRIKA Science and Technology Park (IKBFU):
The usage of high-voltage short impulses allows us to reduce gas temperature in a plasma stream. This method helps to obtain relatively low plasma temperature that is comfortable for human body. The results of our work can be used to develop low-temperature plasma steam devices for medical purposes such as treating purulent-septic wounds.
Fig 1. A helium plasma stream under short-impulse agitation.