β-Dispersion of blood during sedimentation

Abstract

Aggregation of human red blood cells (RBC) is central to various pathological conditions from bacterial infections to cancer. When left at low shear conditions or at hemostasis, RBCs form aggregates, which resemble stacks of coins, known as ‘rouleaux’. We experimentally examined the interfacial dielectric dispersion of aggregating RBCs. Hetastarch, an RBC aggregation agent, is used to mimic conditions leading to aggregation. Hetastrach concentration is incrementally increased in blood from healthy donors to measure the sensitivity of the technique. Time lapse electrical impedance measurements were conducted as red blood cells form rouleaux and sediment in a PDMS chamber. Theoretical modeling was used for obtaining complex permittivity of an effective single red blood cell aggregate at various concentrations of hetastarch. Time response of red blood cells’ impedance was also studied to parametrize the time evolution of impedance data. Single aggregate permittivity at the onset of aggregation, evolution of interfacial dispersion parameters, and sedimentation kinetics allowed us to distinguish differential aggregation in blood.

Simultaneous quantitative detection of hematocrit and hemoglobin from whole blood using a multiplexed paper sensor with a smartphone interface

“…High impedance values spanning over the range of 40 Hz to a few kHz could be ascribed to electric double layer (EDL) phenomena. 50–52 This trend was followed by a frequency regime spanning from 30 kHz to 100 MHz over which the bulk impedance value could be retrieved, as shown in Fig. 2A.…”

“…42 Errors due to the false decrement of Hb values on account of inadequate hemolysis or sample mixing have also been reported in the context of using standard correlations for determining the Hct level. 43 Consequently, such a correlation-based methodology [48][49][50][51] appears to be scientifically flawed as well as technologically challenged. In contrast, simultaneous yet independent experimental measurements of the Hct and Hb levels appear to be a more robust foundation of obtaining the desired hematological information to facilitate appropriate clinical decision making.…”

Non-invasive blood sugar detection by cost-effective capacitance spectroscopy

“…However, there is no specific choice of frequency found in the literature for conducting capacitance or dielectric spectroscopy, indeed, low frequencies are used to get the benefit of deep penetration inside the tissue (Yilmaz et al, 2019). In addition, low-frequency range is advantageous due to the presence of β dispersion below 1 MHz frequency range which originates from the charging of the cell membrane and eventually contributes to the overall cell membrane capacitance (Desouky, 2009;Sabuncu et al, 2021).…”

Red Blood Cell Sedimentation Index Using Shear Stress of Blood Flow in Microfluidic Channel

“…In contrast, RBCs disaggregate at higher shear flow rates. RBC aggregation is highly dependent on aspects such as the membrane viscoelasticity, surface charge, and plasma protein [ 4 , 5 ]. As RBC aggregation provides quantitative information on the individual or interaction effects of plasma and RBCs [ 6 ], it has been regarded as a promising indicator for detecting infections, cardiovascular diseases, metabolic disorders, and hematological diseases [ 7 , 8 , 9 ].…”

“…Several techniques have been applied to quantify RBC aggregation or the ESR, including those based on electrical impedance [ 5 , 12 , 13 , 14 , 15 ], optical light intensity [ 7 , 16 , 17 ], microscopic image intensity [ 18 , 19 ], interface detection in the tube [ 11 , 20 , 21 ], a holographic laser tweezer [ 6 ], and the shear stress in microfluidic device [ 22 ]. Additionally, an external mechanism (e.g., a pinch valve [ 16 ], vibration motor [ 7 ], driving syringe [ 20 ], or vacuum pump [ 22 ]) can be adopted to periodically run or stop the blood flow in a microfluidic channel.…”