RESUMO
For the study of biological effects of direct current (DC) and extremely low frequency (ELF) electric fields, we have quantitatively analyzed red blood cell (RBC) movement in whole blood. Considering the inhomogeneous distribution of electric fields in vivo, five different electric field distributions were generated under a microscope. For theoretical analyses, we assumed electrophoresis and dielectrophoresis as basic motive forces and obtained the spatial distribution of blood cell velocity. The RBC velocity was measured using video image analysis. The spatial dependence of the velocity showed good agreement with that predicted by theoretical analysis. This result suggests the validity of the theoretical model based on electrophoresis and dielectrophoresis for the study of ELF electric field exposure to inhomogeneous animal and human bodies. Next, using the same measurement system, we attempted to find the electric field strength at which these effects occur. The threshold values were found to be 0.40 and 1.6 kV/m, respectively, for DC and AC electric field exposures. Furthermore, we investigated the reproducibility of the field effects in more realistic conditions of human exposure. The RBCs in microchannels were exposed to the electric field generated in capacitive coupling using electrodes separated by an air gap. Even in the new condition, similar effects were observed, which also verified the validity of the analysis described above. These results will provide useful information for the safety assessment of field exposure and for the future biomedical applications of electric fields to manipulate RBCs in vivo.
Assuntos
Campos Eletromagnéticos , Eritrócitos , Animais , Humanos , Campos Eletromagnéticos/efeitos adversos , Reprodutibilidade dos Testes , Eletricidade , Modelos TeóricosRESUMO
To evaluate hematological effects of direct current (DC) and alternating current (AC) extremely low frequency (ELF) electric field exposure, this study investigated red blood cell (RBC) movement in whole blood. Video images of RBCs were recorded under a microscope using specially designed electrode systems. Video analysis software was then used to measure the RBC velocity. The noise level and measurement system stability were confirmed based on results of a no-field exposure experiment. Using the electrode system to produce a non-homogeneous electric field, different movements were found to occur in DC and AC field exposure. The RBCs moved in the directions of the electric field and the gradient of field distribution, respectively, in the DC and AC fields. Dependences of the RBC velocity on the field strength were, respectively, linear and quadratic in the DC and AC fields. These results suggest that electrophoretic and dielectrophoretic movements were, respectively, dominant in the DC and AC fields. The magnitude of the electric field necessary to cause these effects was found to be 103 -105 times greater than the internationally publicized guideline for human safety. © 2022 Bioelectromagnetics Society.
Assuntos
Eletricidade , Movimento , Movimento Celular , Eritrócitos , HumanosRESUMO
To elucidate the mechanism of the biological effect of ELF (extremely low frequency, 0-300 Hz) electric field and to settle appropriate safety standards, the body hair movement in AC electric field exposure was analyzed. We derived the equation of motion to describe the body hair movement cause by the electric force, and obtained an analytic solution for AC input. We applied this solution to practical conditions and clarified the body hair movement in AC electric field exposure. Using this solution, we analyzed the body hair movement in different humidity and verified the validity of the analysis in experiments.