The detection of influenza A virions with a nanoribbon detector (NR detector) has been demonstrated. Chips for the detector have been fabricated based on silicon-on-insulator nanoribbon structures (SOI nanoribbon chip), using a complementary metal-oxide-semiconductor (CMOS)-compatible technology—by means of gas-phase etching and standard optical photolithography. The surface of the SOI nanoribbon chip contains a matrix of 10 nanoribbon (NR) sensor elements. SOI nanoribbon chips of n-type conductance have been used for this study. For biospecific detection of target particles, antibodies against influenza virus have been covalently immobilized onto NRs. Influenza A virus detection was performed by real-time registration of the source-drain current through the NRs. The detection of the target viral particles was carried out in buffer solutions at the target particles concentration within the range from 107 to 103 viral particles per milliliter (VP/mL). The lowest detectable concentration of the target viral particles was 6 × 10−16 M (corresponding to 104 VP/mL). The use of solutions containing ~109 to 1010 VP/mL resulted in saturation of the sensor surface with the target virions. In the saturation mode, detection was impossible.
Hemorheological disorders in structural and functional parameters of erythrocytes are involved in the pathological process in type 2 diabetes mellitus (DM). Aim: to investigate the feasibility of differential diagnosis of the degrees of rheological disturbances in patients with type 2 DM by dielectrophoresis of erythrocytes. Methods: 62 subjects (58.7 ± 1.6 years) with type 2 DM diagnosed according to the criteria of the ADA were subdivided into two groups: medium (n = 47) and high (n = 15) risk of microcirculatory disturbances (EASD, 2013). Electric and viscoelastic parameters of erythrocytes were determined by dielectrophoresis using an electric optical system of cell detection. Results: the progression of rheological disturbances in the patients with type 2 DM was accompanied by significant decreases in deformation amplitude; dipole moment; polarizability; and membrane capacity; and increases in conductivity, viscosity, rigidity, hemolysis, and formation of aggregates (p < 0.05). Combined use of the parameters increased sensitivity (97.8%) and specificity (86.7%) for diagnosis of rheological disturbances in type 2 DM. Conclusion: the proposed experimental approach possesses low invasiveness, high productivity, shorter duration, vividness of the results. The method allows to evaluate not only local (renal and ocular) but also systemic status of microcirculation using more than 20 parameters of erythrocytes.
Possible early diagnostic application of optical methods (dielectrophoresis, spectral and imaging ellipsometry, Fourier-transform infrared spectroscopy, Raman spectroscopy) in studies of red blood cells and serum of patients with diffuse liver disease with varying degrees of fibrosis has been evaluated. Application of combined optical methods was confirmed to significantly improve the performance of sensitivity, specificity, and accuracy index as well as to achieve the reliable results in diagnosis of both severe fibrosis and slight ulterior liver fibrosis. Identified diagnostic potential of optical methods can be effectively utilized in noninvasive screening evaluation of stages of diffuse liver disease of various geneses.
This article contains the results of research on the topical problem of highly sensitive express registration of biological objects using field-effect transistors with the surface open for analyte access, which are made based on silicon-on-insulator (SOI) films. The possibilities of dielectrophoretic effects for controlling the concentration of the analyte in the area of sensory elements are considered on the example of the indication of viruses of nuclear polyhedrosis and vaccinia. It is shown that the use of the dielectrophoresis (DEPh) effect makes it possible to solve (1) the key tasks for creating sensor systems: increasing the detecting ability, as well as exrtacting and verifying the signal from the target particles; and (2) the fundamental task: determining the charge state of the analyte in solutions without modifying the sensors' surface. The problems and prospects of the mass application of nanowire (NW) biosensors, including those with the dielectrophoretic effect, in biotechnology, virology, etc., are discussed.