In this article, which was published in a prominent journal Plasma Processes and Polymers, we investigated differences in the etching rates of blood proteins such as albumin and fibrinogen as a function of a flux of plasma radicals which are found in the early and late afterglow of oxygen plasma. We confirmed a hypothesis about the synergistic effect of neutral oxygen atoms and metastable oxygen molecules, which are found in the afterglow region of oxygen plasma. Both types of particles play a key role in the surface reactions that lead to the etching process. Also it should be noted that we have received very good reviewer’s report about this article, where he/she confirmed that this is the first such study in the world.
COBISS.SI-ID: 27395879
In this article we investigated the difference in the etching rates of blood plasma, different blood proteins and polymer. It has been shown that there are significant differences in the etching rates of blood plasma and blood proteins in comparison with the polymer. Namely, the polymer is etched very slowly in comparison to proteins. Very interesting results regarding etching rates were obtained for blood plasma which has a much more complex structure compared to the proteins. It was found that etching rates of blood plasma are similar to etching rates of proteins. With these results, we finally confirmed that oxygen plasma can be successfully used as a method for cleaning of polymer materials, since any protein contamination can be removed from the surface much before the etching of polymer begins.
COBISS.SI-ID: 27994663
The goal of the project is not just development of the method for surface cleaning of polymer medical instruments, but also development of procedure based on plasma treatment for minimizing protein adsorption to the polymer surface and thus preventing excessive contamination of medical instruments. In this scientific paper we have studied the adsorption of different proteins to plasma treated polymer substrates with Quartz crystal microbalance (QCM). Polymer substrates were made either super-hydrophilic either super-hydrophobic by the use of appropriate gas. It was found that after certain conditions proteins are less bound to the polymer surface. This was explained by the right combination of the surface roughness and functionalization.
COBISS.SI-ID: 27136551
Films of polyethylene terephthalate were deposited on quartz crystals and exposed to oxygen atoms to study their etching characteristics and quantify the etching rate. Oxygen (O) atoms were created by passing molecular oxygen through plasma created in a microwave discharge. Before exposure to oxygen atoms, a thin polymer film of polyethylene terephthalate (PET) was deposited uniformly over a crystal with a diameter of 12 mm. The crystal was mounted on a quartz crystal microbalance to accurately determine the thickness of the polymer film. The polymer film was exposed to O atoms in the flowing afterglow. Samples were treated with O atoms for different periods of up to 120 min. The thickness of the film decreased linearly with treatment time. After 90 min of treatment, a 65-nm-thick polymer film was completely removed. Therefore, the etching rate was 0.5 nm/min, so the interaction probability between an O atom and an atom in the sample was extremely low, just 1.4x10-6.
COBISS.SI-ID: 16102166
In order to get a correlation between the measured etching rates and the flux of oxygen radicals to the surface, we need to know the density of oxygen atoms in the plasma. Therefore, the measurements of the density of oxygen atoms at different parameters (pressure and discharge power) were performed and are presented in this article. We used a sensor which is actually a catalytic probe which is composed of fiber optics and infrared detection system to measure the gray body radiation of the catalyst. The density of neutral atoms can be determined from the temperature curve of the probe, because the catalyst is heated predominantly by the dissipation of energy caused by the heterogeneous surface recombination of neutral atoms. The advantages of this sensor are that it is simple, reliable, easy to use, noninvasive, quantitative and can be used in plasma discharge regions. Sensor design, operation, example measurements and new measurement procedure for systematic characterization are presented.
COBISS.SI-ID: 25707047