Cold Atmospheric Plasma Treatment of Medical Devices

Kotov Dmitry1, Krivenchuk Dmitry2, Osipov Anatoly1, Patseev Sergey3, Aksiuchyts Alexander1, Ponomarenko Gennady4 and Kulchitsky Vladimir*2 1Belarusian State University of Informatics and Radioelectronics, Belarus 2Institute of Physiology, National Academy of Sciences, Minsk, Belarus 3First Minsk City Clinical Hospital, Belarus 4Federal Scientific Center of Rehabilitation of the Disabled named after G.A. Albrecht of the Ministry of Labour and Social Protection of the Russian Federation, Russia


Introduction
Medical devices are used for diagnosis and prevention [1,2], therapy [2,3], rehabilitation of patients, and depending on the purpose, require sterilization in accordance with related regulations [4]. Unfortunately, the sterilization process is associated with some damage to medical devices, depending on its intensity.
Thus, the development of effective and gentle sterilization methods for medical devices is important and not yet resolved. The article presents material on the advisable use of cold atmospheric plasma for medical devices processing [1,4,5]. Cold atmospheric-pressure plasma (CAPP) is a mixture of neutral and metastable atoms and molecules of gas that provides heating of the object under treatment to a temperature of not more than 40° C [1][2][3][4][5]. One of the possible application areas is to modify the surfaces of various materials in order to improve adhesion and hydrophilicity properties. When processing the material under atmospheric pressure plasma, the surface is decontaminated and sterilized. Cleaning is carried out by the interaction of the plasma jet (generated due to the gas-dynamic acceleration of the working gas) with the surface of the material.
In this case, physically adsorbed impurity particles are removed or a chemical reaction with gases occurs with the transfer of reaction products into the gas phase, as well as cleaning by gas-plasma flows is observed. As a result of these processes, it is possible to achieve a significant increase in the wettability of materials of various nature.
In addition, during the activation of the surface, free radicals are formed, and a chemically active surface layer is formed. In this paper, we studied the effects of CAPP on materials widely used in healthcare: medical steel (scalpels, clamps, dental instruments, etc.), glass (laboratory glass, dishes, etc.), polyamide material (surgical sutures, prostheses and orthopedic products, etc.), latex (medical gloves, etc.) [1,6,7]. Increasing the hydrophilicity of the surface of medical devices made of the materials under study will significantly improve their performance properties [8].

Materials and Methods
During the study we processed the surface of the K8 glass, AISI-304 stainless steel, polyamide, and latex by cold plasma of atmospheric pressure ( Figure 1). The treatment of materials surface was carried out using an experimental set-up, the schematic illustration of which is shown in Figure 1. The set-up consisted of a balloon with  S is the area bounded by the curve ( ) t ϕ and y-axis. At regular intervals ∆t, the area S is calculated in accordance with the following formula: where i is the consecutive number of the contact angle measurement, i=0…n.   The effective processing time for polyamide is eff T =20.5 sec. Graphs of the dependence of the distance from the end of the discharge device on the contact angle of polyimide and latex at 30 sec plasma treatment are shown in Figure 6. The presented graphs show that the maximum wettability is achieved at the minimum distance from the end of the discharge device to the surface at which the studies were performed (for latex it is 0.5 cm, for polyamide it is 1 cm). The presented dependencies do not have any extrema similar to steel or glass and are monotonously increasing.

Conclusion
The following results were obtained based on the study conducted.

1.
It was confirmed that atmospheric plasma changed the  specialists in the field of sanitary hygiene will be involved. It is also planned to experimentally adjust required time intervals exposure, the optimal duration and intensity of exposure, as well as the series of procedures.