On-chip estimation of hematocrit level for diagnosing anemic conditions by Impedimetric techniques.

An on-chip device has been fabricated on Si platform for precise estimation of the hematocrit (Hct) level of human blood with rapid turn out. Impedance/capacitance spectroscopy and current-voltage (I-V) measurements have been employed to observe the variation of electrical parameters of erythrocyte suspensions with varying Hct level. Experimentally obtained values of capacitance, impedance and conductance with Hct level suggests a linear variation. Current-time measurement has also been performed to ensure the susceptibility of red blood cells under a fixed external electric field for certain duration of time. The online real time sample analyzes have also been performed by the device connected with an embedded electronic circuit interfaced with a laptop through appropriate software. This has enabled the development of a novel Si-chip based compact point-of-care (POC) diagnosis system for Hct level estimation by measuring the dielectric/capacitive variation of an erythrocyte cell suspension. The relevant performance parameters of such a compact system including range, resolution, limit of detection and throughput have also been evaluated.

Dielectric properties of plasma membrane: A signature for dyslipidemia in diabetes mellitus.

Dielectric properties of a living biological membrane play crucial role indicating the status of the cell in pathogenic or healthy condition. A distinct variation in membrane capacitance and impedance was observed for peripheral blood mononuclear cell (PBMC) suspensions for diabetic and diabetic-dyslipidemic subjects compared to healthy control. Low frequency region were explicitly considered in electrical analysis to address complex membrane dielectric factors that alter the system capacitance of a PBMC suspension. Such variation was marked in size, morphology and membrane function of PBMCs for control and diseased cases. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies reveal significant alteration in surface morphology of PBMCs in diseased condition. Side scatter of flow cytometry reveals complexity of PBMCs in diseased condition. Changes in size between groups were not found by SEM and forward scatter. Functional alteration in PBMCs was manifested by significant changes in cell membrane properties like Na+, K+ ATPase and Ca2+, Mg2+ ATPase activity, reduced plasma membrane fluidity and changes in intracellular Ca2+ content, which bear significant correlation in diabetic and diabetic dyslipidemic subjects. Therefore, dielectric parameters of PBMCs in diabetic-dyslipidemic challenges may led to interesting correlation opening the possibility of identifying crucial signature biomarkers.

FT-MIR supported Electrical Impedance Spectroscopy based study of sugar adulterated honeys from different floral origin.

This study sought to detect the presence of sucrose as an adulterant in selected honey varieties from different floral origins by employing Electrical Impedance Spectroscopy (EIS) technique which has been simultaneously supported by Fourier Transform-Mid Infrared Spectroscopy (FT-MIR) measurements to provide a rapid, robust yet simple platform for honey quality evaluation. Variation of electrical parameters such as impedance, capacitance and conductance for 10%, 20%, 30%, 40%, 50%, 60% and 70% (w/w) sucrose syrup (SS) adulterated honey samples are analyzed and their respective current-voltage (I-V) characteristics are studied. Capacitance, conductance and net current flowing through the system are observed to decrease linearly whereas system impedance has been found to increase similarly with the increase in adulterant content. Also, FT-MIR measurements in the spectral region between 1800cm-1 and 650cm-1 reveal the increment of absorbance values due to the addition of SS. Full-Width-at-Half-Maximum (FWHM) is estimated from the spectral peak 1056cm-1 for all pure and adulterated honey samples and is observed to be linearly increasing with increase in adulterant content. Finally, the coefficient of sensitivity has been extracted for all varieties of honey considered in terms of the measured conductance values.