The electrokinetic possibilities of separation and concentration of S.aureus bacteria in human whole blood (test mixture) were studied using a new design of a four-electrode biosensor chip format with transparent microelectrodes. In the measurements, a closed cell was used, into which the test mixture was poured. The electrokinetic movement of bacteria during concentration was observed when AC voltage was applied to the first and second annular external electrodes, and DC voltage was applied to the third and fourth semicircular central electrodes. The process of separation of erythrocytes and concentration of bacteria was recorded by an optical method. It is shown that the concentration of bacteria appears after 8 minutes and increases by 30 minutes in the region of the central electrodes under model conditions. The measurements were carried out on two biosensor chip formats having almost identical electrophysical parameters of capacitance and conductivity at frequencies from 100 Hz to 1 MHz. It is determined that the amplitude-frequency mode and biosensor chip format can be used to develop methodological support for the identification of bacterial species, but only by optical methods. It is shown that in order to increase the number of bacteria on both of the central electrode in the concentration mode, it is necessary to increase the speed of the electroosmotic flow at alternating current, by optimizing the composition of the medium and the parameters of the electrical regime in order to equalize the rates of separation and concentration processes.

Using the example of mixed suspensions of S.aureus bacteria and human erythrocytes, it was shown that regardless of the number of cells in the mixed suspension, all the studied bioprocessor chip formats, based on indium tin oxide (ITO) microelectrodes, demonstrate the same mechanisms of the electrokinetic bioprocesses occurring associated with separation and by concentrating cells of various sizes. The result obtained is in good agreement with the results of [6], from which it follows that with an appropriate electrical mode and a frequency of 800 Hz, blood cells experience a negative dielectrophoretic force, which pushes them out of the surface of the central electrode, because it is stronger than the electrohydrodynamic force responsible for dragging the cells account electroosmotic flow AC voltage. It has been shown that bacteria are transported to the central electrode area due to the electroosmotic flow, since the electrohydrodynamic force for bacteria is greater than their positive dielectrophoretic force, and the dielectrophoretic force pushing blood cells pulls bacteria to the middle of the central electrode, where electrohydrodynamic force is the weakest, and dielectrophoretic and electrophoretic force are the biggest.

It is shown that the silanization of the surface assists enhancement of homogeneous polarization properties of the passivating cover on base of the nanoporous aluminum oxide in non-faraday capacitance sensors, usable for studying of the microorganisms' growth. A new immunochemical method of differentiated diagnostics of the A(H1N1) B influenza viruses is proposed.

Sensitivity of non-Faradaic impedance sensors for bacterial detection E.coli in Kessler culture medium is investigated. It is shown that for reduction of time of bacterial detection in the range (102…105) CFU/ml non-Faradaic impedance sensors with electrodes covered by a thin film of nanoporous anodic aluminum oxide.

Monitoring of influence of acetylsalicylic acid (ASA) on lipid bilayer conductance may contribute to better understanding of molecular mechanisms underlying passage of ASA into cells. This paper presents effects of increasing sweeping potential on stability of egg yolk phosphatidylcholine planar bilayer lipid membranes (BLM) without or with cholesterol incubated in the presence of ASA. We demonstrated that current flow through bilayer membranes generated fluctuating pores in their structure. Presence of cholesterol in the membrane caused an increase in the value of the breakdown potential, thus confirming that cholesterol had a stabilizing effect on BLM. Otherwise, ASA significantly reduced these values regardless of cholesterol concentration. Overall, by destabilizing the lipid bilayer, ASA contributed to the formation of metastable single pores, which facilitated ASA diffusion through a bilayer. Our data point out that ASA transport across the lipid bilayer takes place predominantly via the process of passive diffusion. In conclusion, the effects of ASA on lipid bilayer stability may contribute to drug transport through membrane lipid bilayers.

The effects of culture media of various compositions on chemiluminescence developing in peroxidase oxidation of luminol with hydrogen peroxide were under study. The findings evidence that the presence of carbonate and bicarbonate ions in the medium results in a two-staged chemiluminescence kinetics and in more intensive chemiluminescence in the peroxidase-luminol-hydrogen peroxide system. This fact has brought the authors to a conclusion that carbonate and bicarbonate-containing media are more effective for the detection of low peroxidase concentrations by the chemiluminescence technique.

The dynamic conductivity of bilayer lipid membranes unmodified by ionophores in current ranges of 10(-12)-10(-10) A was studied. On the current voltage characteristics the jumps of dynamic conductivity in the voltage ranges near zero and disruption value were observed. The lifetime of these jumps was 1-5 s. It was shown that these effects were due to electrostriction phenomena and defects in the bilayer lipid structure correspondingly. Apparently, lipid peroxidation products participate in the building of defects in lipid bilayers.