Effect of static magnetic field on erythrocytes characterizations

doi:10.4236/jbise.2010.33040

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J. Biomedical Science and Engineering, 2010, 3, 300-303

doi:10.4236/jbise.2010.33040 Published Online March 2010 (http://www.SciRP.org/journal/jbise/

JBiSE

Published Online March 2010 in SciRes. http://www.scirp.org/journal/jbise

Effect of static magnetic field on erythrocytes characterizations

Mohamed A. Elblbesy

Medical Biophysics Department, Medical Research Institute, Alexandria University, Alexandria, Egypt.

Email: [email protected]

Received 29 November 2009; revised 15 December 2009; accepted 28 December 2009.

ABSTRACT

The interaction of static magnetic field (SMF) with

living organisms is a rapidly growing field of investi-

gation. Recently, exposure to moderate intensity

SMFs (1 mT – 1 T) has attracted much attention for

its various medical applications. This study was de-

signed to show the microscopic effect of SMF on

erythrocytes in vitro. For this purpose SMF system

was constructed in my lab on basis of the idea of cell

tracking velocimetry system. The changes in eryth-

rocytes surface area, sphericity, and adhesion num-

ber for erythrocytes were calculated to quantify the

effect of SMF on erythrocytes characterizations. The

results showed that SMF increased erythrocytes sur-

face area and reduced their sphericity. The adhesion

number of erythrocytes under the influence of SMF

showed the tendency of erythrocytes to adhere with

each other. These findings indicate that more study

on microscopic scales must be carried out in order to

investigate the effect of SMF on erythrocytes.

Keywords: Static Magnetic Field; Erythrocytes;

Surface Area; Shericity, Adhesion

1. INTRODUCTION

During the last few years there has been an increasing

interest in the influence of magnetic field on biological

cell [1]. Many attempts have been made to measure the

magnetic effects. Historically, there are several signifi-

cant studies in the field of erythrocyte rheology [2].

Reports from in vitro research indicate that low level

high frequency fields may alter membrane structural and

functional properties that trigger cellular responses. It

was hypothesized that the cell membrane may be sus-

ceptible to low level high frequency fields, especially

when these fields are amplitude modulated at extremely

low frequencies [3]. There are abundant data on the ef-

fects of weak physical signals on cell functional activity.

However cell targets for these signals are not established

yet. Since water is the main component of biological

systems and all metabolic processes take place in aque-

ous medium it was supposed that even minor changes in

the physico-chemical properties of water could signifi-

cant modify cell functional activity. The data about the

effect of EMF on water specific electrical conductivity

and wheat sprouting serve as an additional evidence for

the hypothesis according to which the EMF-induced

water structure changing is an important pathway

through which the biological effect of EMF is realized

[4].

Most of the theories addressing the mechanism of in-

teraction between biological systems and MFs suggest

that the plasma membrane, by virtue of its bioelectrical

properties, is the site, where MFs exert their primary

effects [5]. To investigate the effect of static magnetic on

biological system, it is necessary to clarify interaction

mechanisms of magnetic field with biological systems.

Simple components of biological system, as cells, bio-

molecules, artificial membrane, are used in vitro studies

that allow reducing of biological variables and more

precisely defining and controlling the exposure parame-

ters, compared with in vivo exposure. Erythrocytes are

often used as model in exploring the structure and func-

tion of the biological cells as well as studying the effect

of different physical and chemical factors on the cell.

The present study was established to elucidate the

changes in biological cells interaction and morphological

characterization through in vitro exposure of human

erythrocytes to SMF.

2. MATERIALS AND METHODS

2.1. Samples Collection and Preparation

Twenty blood samples of 5 ml were collected from

healthy volunteers of the same age and gender. The

blood samples were centrifuged and erythrocytes were

separated. Erythrocytes were washed three times in

0.155 M NaCl (2,000 rpm for 10 min). After the final

centrifugation suspension were diluted to final erythro-

cytes concentration 2% in phosphate buffer slain (PBS).

2.2. SMF System

The SMF system was constructed in my lab. SMF sys-

tem is based on the idea of cell tracking velocimetry

system. In this system the movement of cells in a well

M. A. Elblbesy / J. Biomedical Science and Engineering 3 (2010) 300-303

301

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defined magnetic field is videotaped [6]. Erythrocytes

suspension were placed in a glass sample holder and

viewed using an inverted optical microscope in conjunc-

tion with a computer linked via digital camera and image

capture software. Two rod of iron to produce a magnetic

field with large gradient, were placed on both sides of

sample holder. The iron rods were alternately magnet-

ized by solenoids controlled by a DC power supply.

When magnetized, the magnetic field produced by each

rod exerted a force on erythrocytes directed towards the

edge of the rod.

2.3. Erythrocytes Surface Area and Sphericity

Erythrocytes were suspended in phosphate buffer saline

(PBS) at concentration of 5%. The erythrocytes suspen-

sion was placed on the sample holder of SMF system.

Image of unexposed erythrocytes (control) was taken

then the magnetic field was turned on and the image of

exposed erythrocytes was captured. For each value of B

images of exposed erythrocytes were compared with

control by imaging processing software in order to cal-

culate the changes in erythrocytes surface area Ach and

sphericity of each erythrocyte in the image.

The change in erythrocytes surface area was calcu-

lated as the following:

 (1)

where Ach is the change in erythrocytes surface area, AEx

is the surface area of the erythrocytes after exposed to

SMF, and A0 is the surface area of unexposed erythro-

cytes.

Ach was calculated as the average of 100 erythrocytes

for each image. It was taken that if Ach greater than one

there was an increase in erythrocytes surface area, and if

Ach smaller than 1 there was a decrease in erythrocytes

surface area.

The sphericity of an erythrocyte is a dimensionless

parameter first described by Canham and Burton [7] and

is a measure of how spherical a cell is, with values be-

tween 0 and 1, for a sphere and laminar disk, respec-

tively. It was calculated as the following:

Sphericity4.84 A

 (2)

where V is the volume of erythrocytes and is taken to be

88.5 µm3.

2.4. Erythrocytes Adhesion Number

Five volume fractions (0.00001, 0.00003, 0.00005,

0.00007, 0.00009) of erythrocytes suspensions in PBS

were prepared by further dilution of the main erythro-

cytes suspension. The erythrocytes suspension was

placed in sample holder of SMF system. For each sam-

ple counting of doublets erythrocytes (N2) and singlet

erythrocytes (N1) was performed. The plot of doublet to

singlet ratio versus particle volume fraction should yield

a straight line passing through the origin. The gradient of

the line is a measure of the adhesion number. The same

previous procedure was performed with SMF turned on

to calculate the adhesion number of exposed erythro-

cytes.

2.5. Statistical Analysis

The data was present as the mean ± SD. For each plot,

correlation (R2) was calculated using Microsoft Excel.

3. RESULTS

The erythrocytes surface area increased as the value of

magnetic field intensity increased (Figure 1). A strong

correlation was found between Ach and B (mT) (R2 =

0.95). At low magnetic field the increased in erythro-

cytes surface area was slightly small. At higher values of

magnetic field the increased in erythrocytes surface area

raised.

The sphericity of the erythrocytes is inversely propor-

tional to the applied SMF (Figure 2). Under the influ-

ence of SMF, the sphercity of erythrocytes was reduced

by about 35 % in comparison with unexposed erythro-

cytes. The decrease in erythrocytes sphericity was re-

duced rapidly when SMF was applied. A small decrease

in sphericity was recorded at higher values of B.

As indicated in Figure 3, The adhesion number in-

creased under the influence of SMF. Acute increase in

adhesion number was indicated at 15 mT. A strong rela-

tion between adhesion number and B was pointed out (R2 =

0.96).

4. DISCUSSION

It is generally known that morphological and structural

changes to the plasma membrane interfere with many

functional and structural features of the cells, leading,

Figure 1. Erythrocytes surface area increased as the values of

SMF intensity increased. Strong correlation between Ach and B

was observed (R2 = 0.95).

302 M. A. Elblbesy / J. Biomedical Science and Engineering 3 (2010) 300-303

Figure 2. Sphericity of erythrocytes decreased under the in-

fluence of SMF. The correlation between sphericity and B is

strong (R2 = 0.765).

Figure 3. Sharp increase in erythrocytes adhesion number

according to increase in SMF intensity (B).

for example, to changes in cellular shape, cytoskeleton

arrangement, ion flux, receptor distribution, phagocyto-

sis etc. Modifications in cell shape and plasma mem-

brane as a consequence of exposure to MFs or EMFs

have also been reported in many different cells [8,9,10].

Moderate-intensity (6 mT) SMFs exert a strong and rep-

licable effect on cell shape and plasma membrane of dif-

ferent cell types [9]. In spite of the fact that this is not a

high-intensity magnetic field, it is nevertheless able to

produce changes in cell structure and function. Chionna

et al. [9] focused their research on cell shape and cell

surface modifications, providing evidence for time-re-

lated changes. As a general effect, cells growing in sus-

pension lost their round shape and became irregularly

elongated, while cells growing attached modified their

shape and orientation or detached themselves, becoming

freely suspended in the culture medium. Consistent with

the previous studies increased in surface area and de-

creased in sphericity of the erythrocytes were found in

the present study. The increased in erythrocytes surface

area was at the expense of regular shape of the erythro-

cytes.

Dilek Ulker Cakir et al. [11] showed that long-term

exposure to ELF-EMF decreased the mean volume of

thrombocytes in the group of rats exposed for 50 days.

Sanjay Jayavanth [12] showed that erythrocytes were

monodisperse and with the formation and sedimentation

of erythrocytes aggregates. In agreement of the previous

studies our results showed that the adhesion of the

erythrocytes increase under the influence of SMF com-

pared to control.

From this study it can be concluded that studying the

effect of SMF on the microscopic scale give a clear vi-

sion about the mechanisms of interaction between living

cell and SMF. Also, it could be suggested that the SMF

my increase the erythrocytes adhesion hence erythro-

cytes aggregation. It must be take in a count the changes

of erythrocytes morphological structure when dealing

with SMF.

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