The Effect of Temperature and Additives on the Dielectric Behavior of Human Whole Blood, Its Different Components, and Cell Suspensions

This investigation involves the study of electrical properties, i.e., conductivity and permittivity of human whole blood and its different components with/without various additives at different temperatures. The open-ended coaxial probe measurement technique was employed to perform the study for the frequency range of 0.3–6.5 GHz. The dielectric behaviors of the freshly received whole blood from five different donors with different anticoagulants and clotting gel were studied at temperatures ranging from 5 °C to 45 °C. The differences in the dielectric behaviors of the whole blood, its different components [packed red blood cells (RBCs), plasma, and serum], and RBC suspensions were also analyzed. The plain whole blood and the whole blood samples incorporated with the clotting gel exhibited lower dielectric behaviors compared to those with the whole blood samples incorporated with the anticoagulants. The analysis of the whole blood, its different components, and RBC suspensions inferred that the packed RBCs exhibited the lowest dielectric constant, loss, and conductivity, and these values were increased for the whole blood followed by serum, plasma, and RBC suspensions, respectively. The dielectric behaviors of the whole blood and its components were observed to be significantly affected by the presence of different additives and also due to the variation in frequencies and temperatures. The modified Debye relaxation model included with the static conductivity term was fitted to the measured permittivity. The dielectric responses of biological samples are very useful and paramount for understanding the specific absorption rate (SAR) and other thermal and nonthermal effects of the radiation.