Dielectrophoretic profiling of erythrocytes to study the impacts of metabolic stress, temperature, and storage duration utilizing a point-and-planar microdevice.

Dielectrophoresis (DEP) is widely utilized for trapping and sorting various types of cells, including live and dead cells and healthy and infected cells. This article focuses on the dielectric characterization of erythrocytes (red blood cells or RBCs) by quantifying DEP crossover frequency using a novel point-and-planar microwell device platform. Numerical simulations using COMSOL Multiphysics software demonstrate that the distribution of the DEP force is influenced by factors such as the shape of the point electrode, spacing between the point and planar electrodes, and the type of bioparticle being investigated. The dependency on electrode spacing is experimentally evaluated by analyzing the DEP crossover response of erythrocytes. Furthermore, the results are validated against the traditional electrical characterization technique called electrorotation, which typically requires laborious fabrication and operation using quadrupole electrodes. Other significant factors, including erythrocyte storage age and the changes in cell properties over time since collection, osmolarity, and temperature, are also assessed to determine the optimal conditions for erythrocyte characterization. The findings indicate a significant difference between fresh and stored erythrocyte samples (up to 4 days), highlighting the importance of maintaining an isotonic medium for cell storage.

Dielectric characterization of Babesia bovis using the dielectrophoretic crossover frequency.

Coinfection with the tick-transmitted pathogen Babesia spp. is becoming a serious health problem because of the erythrocyte invasion through Ixodes scapularis tick. The transmission of this protozoan by blood transfusion often results in high morbidity and mortality in recipients. A novel way to detect parasitized erythrocytes is by utilizing dielectrophoresis, an electrokinetic technique on a microfluidic platform, to improve the diagnostics of Babesia spp. The differences in the dielectric properties of Babesia spp.-infected erythrocytes versus healthy erythrocytes were exploited to design a fast and cost-effective diagnostic tool. One crucial factor for a successful diagnostic platform via dielectrophoretic separation is the dielectric characterization of Babesia-infected erythrocytes, which is investigated in this paper. The influence of medium conductivity and erythrocytes phenotype and genotype over the first crossover frequency (fco1 ) are used to quantify the dielectric properties of the infected cells. A sigmoidal curve was plotted via curve fitting of the single-shell model, which has been proven appropriate for parasitized cell populations where considerable cell geometry variation occurs. The difference in these curves is relevant for the separation of cells population. Microliters of sample and reagent were used throughout this experiment; the scale, results obtained, and simplicity of the system often make it very suitable for point-of-care babesiosis disease diagnostics.