Orientation of erythrocytes in a strong static magnetic field

Abstract

The frequency of exposure to strong magnetic fields has increased as the magnetic-resonance image-diagnostic technique (MRI) and passenger transport systems based on the principle of magnetic levitation have come into wider use. Accordingly, it has become necessary to more systematically assess their influence on the body and set strict guidelines on acceptable limits of magnetism exposure. Therefore, we have assessed the influence of an uniform static magnetic field (8 T in maximum) on normal erythrocytes. The erythrocytes were oriented with their disk plane parallel to the magnetic field direction. These erythrocytes were influenced even by 1 T and almost 100% of them were oriented when exposed to 4 T. Furthermore, the degree of orientation was not influenced by the state of hemoglobin (oxy: diamagnetic, deoxy and met: paramagnetic). The dependence of the measured degree of orientation on the intensity of the magnetic field was in good agreement with the theoretical equation for the magnetic orientation of diamagnetic substances. As a result of a numerical analysis based on the equation, the anisotropic diamagnetic susceptibility of erythrocytes was found to be delta chi = 8 x 10(-22) electromagnetic units/erythrocyte. It was almost in agreement with the calculated value delta chi = 6 x 10(-22) emu/erythrocyte estimated from the diamagnetism of the membrane constituents of erythrocyte.

Strong Static Magnetic Field Stimulates Bone Formation to a Definite Orientation In Vitro and In Vivo

“…The MC3T3-E1 cells, which adhered to the culture dish, were magnetically orientated because of their diamagnetic anisotropy. The possible origins of diamagnetic anisotropy of cells are reportedly the cell membranes and intracellular cytoskeleton molecules in erythrocytes (13)(14)(15) and platelets. (16) Because the diamagnetic anisotropy is canceled in spherical or symmetrical shapes cells, the irregular and asymmetrical shapes seen in erythrocytes, platelets, and osteoblasts will result in the large diamagnetic anisotropy of these cells.…”

“…The minimum period of magnetic field exposure for attaining the parallel orientation of MC3T3-E1 cells was 60 h in this study, whereas in floating cells such as erythrocytes and platelets, the regulation of orientation was observed within 1 minute. (13)(14)(15) This difference may be caused by the presence and absence of friction between cells and the culture dish surface, which may prevent the movement of adherent cells. It appears that the magnetic orientation of cells occurs when the diamagnetic torque force overcomes the force of friction.…”

“…Accumulated evidence has revealed that strong magnetic fields of tesla (T ϭ 10,000 gauss) order are capable of regulating the orientation of matrix proteins and cells. (8 -17) Matrix proteins such as collagen fibers (8,9) and fibrin fibers (10 -12) are orientated to a regular pattern under SMF of 5-10 T. Under these SMF conditions, floating blood cells such as erythrocytes (13)(14)(15) and platelets (16) were also reported to orientate parallel to the field direction. Matrix proteins provide a permissive environment for the orientation of cells, for example, smooth muscle cells and endothelial cells in collagen fibers under strong SMF.…”

Effectiveness of magnetically aligned collagen for neural regeneration in vitro and in vivo

“…1984; Kotani et al, 2000] and fibrin aligns parallel [Torbet et al, 1981;Ueno et al, 1993] to the magnetic field when exposed to strong magnetic fields during polymerization. Floating cells such as erythrocytes [Higashi et al, 1993] and adherent cells such as osteoblasts [Kotani et al, 2000[Kotani et al, , 2002 also orientate parallel to the direction of the magnetic field. We previously reported that Schwann cells aligned along collagen fibers oriented by an 8-T magnetic field [Eguchi et al, 2003;Eguchi and Ueno, 2005].…”

“…However, none of these nerve conduits have achieved therapeutic effects comparable to autografts. Recently, many studies have reported that strong magnetic fields of tesla (T)-order could orient an extracellular matrix such as collagen [Torbet and Ronziere, 1984;Kotani et al, 2000] or fibrin [Torbet et al, 1981;Ueno et al, 1993], floating cells such as erythrocytes [Higashi et al, 1993], and adherent cells such as osteoblasts [Kotani et al, 2000[Kotani et al, , 2002. This ability to control orientation of biological materials may be useful in medical and tissue engineering.…”