In this work, we study the interaction of new aluminum oxide nanoparticles produced by the acoustoplasma method with and without cavitation with blood plasma enzyme - thrombin. Using dynamic and static light scattering, we find that the interaction of thrombin with two types of nanoparticles leads to different ways of aggregation. In the case of interaction of thrombin with nanoparticles with cavitation, formed aggregates precipitate during several hours after mixing. In the case of the nanoparticles without cavitation, in the opposite, the stable aggregates are formed with a mean size of 700 nm. The total intensity of scattered light in the solution of thrombin with nanoparticles without cavitation increases 40 times one day after mixing with the maintaining of sizes. According to Rayleigh-Gans-Debye approximation, such an increase of the total intensity of scattered light may be caused by changing of either radius of particles or their concentrations, or refractive index of formed aggregates. Due to radius of particles formed remains unchanged, and to increase the concentration by 2 orders in magnitude, it is necessary the material intake (which is absent in the closed cuvette). Therefore, it is the refractive index of formed aggregates that change (Δn=0.3). Moreover, after the addition of thrombin-nanoparticle complexes to fibrinogen solution, the reaction of fibrin gel formation switched off. It testifies inactivation of thrombin under interaction with aluminum oxide nanoparticles (in opposite to the results obtained under the interaction of iron oxide nanoparticles).
In this work, we study the effect of new iron oxide nanoparticles produced by the acoustoplasma method on the rate of formation of a fibrin gel in the enzymatic reaction of fibrinogen-thrombin. According to dynamic and static light scattering, we find that the addition of thrombin, preincubated with the nanoparticles (pH of the solution 7.5), to fibrinogen solution, accelerates the gelation reaction 30 times compared with the system without the addition of nanoparticles. Incubation of the nanoparticles with thrombin with decreased activity due to long storage leads to acceleration of the reaction in 4 times. The addition of thrombin, preincubated with the nanoparticles with less pH of the solution (5.5), to fibrinogen, in the opposite, slows down the reaction on the first stage of the process. During one hour after adding the thrombin-nanoparticles mixture to fibrinogen, the gelation reaction does not start. After this time, the reaction starts, but with the rate of 2 times less than without nanoparticles and 50 times less than with nanoparticles with pH 7.5. Such a difference in the biological effect of iron oxide nanoparticles on the rate of gelation under changing of their water environment pH is determined by the change in their surface charge (zeta-potential) and affinity for the thrombin enzyme.
The effect of iron (III) oxide nanoparticles produced in acoustoplasma discharge with cavitation on the concentration and the sizes of particles in model protein solutions, human blood serum and plasma samples is studied. Dynamic and static light scattering data on size and concentration of particles show that the nanoparticles addition to fibrinogen-thrombin system affects the course of enzymatic reaction. Interaction of nanoparticles with fibrinogen solution (before thrombin addition) does not significantly change the distribution of scattered light intensity on particle sizes. Comparison of the relations of particle sizes and their concentration for fibrinogen solution with and without nanoparticles shows an increase of the slope of size-concentration relation in a log-log scale, which indicates an increase in the concentration of small particles and decrease of big ones. For model solution of fibrinogen with thrombin, initially incubated with iron oxide nanoparticles, the slopes of the size-concentration relation equals to k = –(4.62±0.33) and slightly differs from the slope of the relation for fibrinogen-thrombin system without nanoparticles k=–(4.23±0.28). We believe that changes in the size-concentration relation indicate the interaction of nanoparticles with proteins, which results in gelation rate change.
The characteristics of electrical discharges in liquid media under the influence of intense ultrasonic vibrations are investigated and the difference in dynamic characteristics of discharges before cavitation and after cavitation begins. The experiments carried out during this work made it possible to establish that in a liquid in an intense ultrasonic field above the cavitation threshold there exists a special form of an electric discharge characterized by volumetric luminescence in the entire space between the electrodes and the current-voltage characteristic inherent in an anomalous glow discharge in a gas.
In this paper, differences in the luminescence intensity of nanoparticles of metal oxides synthesized in electric discharges in liquid media under the influence of intense ultrasonic vibrations prior to cavitation and after the start of cavitation regime have been studied. The increase in the luminescence intensity of nanoparticles obtained by ultrasonic cavitation can be explained by the formation of defects in oxide crystals under the influence of intense mechanical action. In the process of synthesis, the particles are exposed not only to the action of electromagnetic fields, but also to shock waves during the collapse of cavitation bubbles, which leads to the formation of defective valence structures and delocalization of electrons.
Nanoparticles of tungsten, copper, iron, and zinc oxides were synthesized in acoustoplasma discharge. Their size distribution was studied by electron microscopy and laser correlation spectroscopy. Ultrasound was found to narrow significantly the size distribution width of zinc oxide nanoparticles. Water suspensions of zinc oxide nanoparticles showed photoluminescence in red and near infrared spectral ranges, which makes them a promising material for luminescent diagnostics of biological systems.
The paper shows, that a low-temperature plasma initiated in liquid media in interelectrode discharge gap is able to decompose hydrogen containing organic molecules resulting in obtaining gaseous products with volume part of hydrogen higher than 90% (up to gas chromatography data). Tentative assessments of energy efficiency, calculated with regard for hydrogen and feedstock heating value and energy consumption, have shown efficiency factor of 60-70%, depending on the source mixture composition. Theoretical model calculations of discharge current and voltage have been performed; the values are in good accordance with experimental data.
The work shows that iron oxide nanoparticles obtained in acoustoplasma discharge with cavitation affect the rate of one of the reactions of the process of blood coagulation - cleavage of fibrinogen by thrombin. As a result of the reaction, a fibrin gel is formed. By means of dynamic and static light scattering we reveal that adding of thrombin initially mixed with nanoparticles to the fibrinogen solution leads to dramatically acceleration of gel formation. Adding of nanoparticles to the solution of fibrinogen (before thrombin addition) leads to stopping of the reaction at the first stage (without gel formation). This data shows that ferrous oxide nanoparticles can act as regulators of enzyme reaction - in one case accelerating it, and in the other - by inhibiting it. Previously we presented the dynamics of distributions of the scattered light intensity on particle sizes in the fibrinogen-thrombin system with various sequences of nanoparticle addition. In this work we showed dynamics of the intensity correlation function in the samples, whose form becomes close to “stretched exponent” in pregel state or power law in a gel.
The work is devoted to the study of sizes and concentrations of proteins, and their aggregates in blood plasma samples, using static and dynamic light scattering methods. A new approach is proposed based on multiple repetition of measurements of intensity size distribution and on counting the number of registrations of different sizes, which made it possible to obtain statistically confident particle sizes and concentrations in the blood plasma. It was revealed that statistically confident particle sizes in the blood plasma were stable during 30 h of observations, whereas the concentrations of particles of different sizes varied as a result of redistribution of material between them owing to the protein degradation processes.
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