Limits...
Lucifer Yellow uptake by CHO cells exposed to magnetic and electric pulses.

Towhidi L, Firoozabadi SM, Mozdarani H, Miklavcic D - Radiol Oncol (2012)

Bottom Line: The Chinese hamster ovary (CHO) cells were exposed to magnetic pulses of 2.2 T peak strength and 250 μs duration delivered by Magstim stimulator and double 70 mm coil.Three different frequencies of 0.25, 1 and 10 Hz pulses with 112, 56 and 28 number of pulses were applied (altogether nine experimental groups) and Lucifer Yellow uptake was measured in each group.Our results show that time-varying magnetic field exposure increases transmembrane molecular transport and this uptake is greater for lower frequencies and larger number of pulses.

View Article: PubMed Central - PubMed

Affiliation: Tarbiat Modares University, Department of Medical Physics, Tehran, Iran ; University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia.

ABSTRACT

Background: The cell membrane acts as a barrier that hinders free entrance of most hydrophilic molecules into the cell. Due to numerous applications in medicine, biology and biotechnology, the introduction of impermeant molecules into biological cells has drawn considerable attention in the past years. One of the most famous methods in this field is electroporation, in which electric pulses with high intensity and short duration are applied to the cells. The aim of our study was to investigate the effect of time-varying magnetic field with different parameters on transmembrane molecular transport.

Materials and methods: 'Moreover, a comparison was made between the uptake results due to magnetic pulse exposure and electroporation mediated uptake.' at the end of Background part. The Chinese hamster ovary (CHO) cells were exposed to magnetic pulses of 2.2 T peak strength and 250 μs duration delivered by Magstim stimulator and double 70 mm coil. Three different frequencies of 0.25, 1 and 10 Hz pulses with 112, 56 and 28 number of pulses were applied (altogether nine experimental groups) and Lucifer Yellow uptake was measured in each group. Moreover, maximum uptake of Lucifer Yellow obtained by magnetic pulses was compared to the measured uptake due to electroporation with typical parameters of 8 pulses of 100 μs, repetition frequency of 1 Hz and electric field intensities of 200 to 600 V/cm.

Results and conclusions: Our results show that time-varying magnetic field exposure increases transmembrane molecular transport and this uptake is greater for lower frequencies and larger number of pulses. Besides, the comparison shows that electroporation is more effective than pulsed magnetic field, but the observed uptake enhancement due to magnetic exposure is still considerable.

No MeSH data available.


Related in: MedlinePlus

(A) Photograph of a 70 mm figure-of-eight coil used in the magnetic pulse exposure experiments. (B) Schematic of Petri dish location under figure-of-eight coil during magnetic field exposure. The direction of current passing through each winding is shown. The direction of resulted electric and magnetic field at the bottom of the Petri dish are displayed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC3472937&req=5

f1-rado-46-02-119: (A) Photograph of a 70 mm figure-of-eight coil used in the magnetic pulse exposure experiments. (B) Schematic of Petri dish location under figure-of-eight coil during magnetic field exposure. The direction of current passing through each winding is shown. The direction of resulted electric and magnetic field at the bottom of the Petri dish are displayed.

Mentions: It has been demonstrated that figure-of-eight coils allow for a more focused and greater peak electric field than simple round coils.31,33 Moreover, the smaller coils induce higher magnetic field intensities than larger coils but the field falls off much more rapidly with distance.31,33 The optimum coil for our experiments in order to deliver the most intense fields with larger decay time constant was a 70 mm figure-of-eight coil with 100% energy transfer (Figure 1A). The magnetic field strength decreases rapidly with the distance from the stimulating coil so that the field strength is peaked close to the coil surface.31,34 Therefore, the Petri dishes containing the cells were placed under the coil where two windings meet and attached to the coil in order to expose cells to the strongest possible magnetic field. The geometry of the coils, the Petri dish in the experiments and direction of current flow through each winding of the coil are shown in Figure 1B.


Lucifer Yellow uptake by CHO cells exposed to magnetic and electric pulses.

Towhidi L, Firoozabadi SM, Mozdarani H, Miklavcic D - Radiol Oncol (2012)

(A) Photograph of a 70 mm figure-of-eight coil used in the magnetic pulse exposure experiments. (B) Schematic of Petri dish location under figure-of-eight coil during magnetic field exposure. The direction of current passing through each winding is shown. The direction of resulted electric and magnetic field at the bottom of the Petri dish are displayed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472937&req=5

f1-rado-46-02-119: (A) Photograph of a 70 mm figure-of-eight coil used in the magnetic pulse exposure experiments. (B) Schematic of Petri dish location under figure-of-eight coil during magnetic field exposure. The direction of current passing through each winding is shown. The direction of resulted electric and magnetic field at the bottom of the Petri dish are displayed.
Mentions: It has been demonstrated that figure-of-eight coils allow for a more focused and greater peak electric field than simple round coils.31,33 Moreover, the smaller coils induce higher magnetic field intensities than larger coils but the field falls off much more rapidly with distance.31,33 The optimum coil for our experiments in order to deliver the most intense fields with larger decay time constant was a 70 mm figure-of-eight coil with 100% energy transfer (Figure 1A). The magnetic field strength decreases rapidly with the distance from the stimulating coil so that the field strength is peaked close to the coil surface.31,34 Therefore, the Petri dishes containing the cells were placed under the coil where two windings meet and attached to the coil in order to expose cells to the strongest possible magnetic field. The geometry of the coils, the Petri dish in the experiments and direction of current flow through each winding of the coil are shown in Figure 1B.

Bottom Line: The Chinese hamster ovary (CHO) cells were exposed to magnetic pulses of 2.2 T peak strength and 250 μs duration delivered by Magstim stimulator and double 70 mm coil.Three different frequencies of 0.25, 1 and 10 Hz pulses with 112, 56 and 28 number of pulses were applied (altogether nine experimental groups) and Lucifer Yellow uptake was measured in each group.Our results show that time-varying magnetic field exposure increases transmembrane molecular transport and this uptake is greater for lower frequencies and larger number of pulses.

View Article: PubMed Central - PubMed

Affiliation: Tarbiat Modares University, Department of Medical Physics, Tehran, Iran ; University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia.

ABSTRACT

Background: The cell membrane acts as a barrier that hinders free entrance of most hydrophilic molecules into the cell. Due to numerous applications in medicine, biology and biotechnology, the introduction of impermeant molecules into biological cells has drawn considerable attention in the past years. One of the most famous methods in this field is electroporation, in which electric pulses with high intensity and short duration are applied to the cells. The aim of our study was to investigate the effect of time-varying magnetic field with different parameters on transmembrane molecular transport.

Materials and methods: 'Moreover, a comparison was made between the uptake results due to magnetic pulse exposure and electroporation mediated uptake.' at the end of Background part. The Chinese hamster ovary (CHO) cells were exposed to magnetic pulses of 2.2 T peak strength and 250 μs duration delivered by Magstim stimulator and double 70 mm coil. Three different frequencies of 0.25, 1 and 10 Hz pulses with 112, 56 and 28 number of pulses were applied (altogether nine experimental groups) and Lucifer Yellow uptake was measured in each group. Moreover, maximum uptake of Lucifer Yellow obtained by magnetic pulses was compared to the measured uptake due to electroporation with typical parameters of 8 pulses of 100 μs, repetition frequency of 1 Hz and electric field intensities of 200 to 600 V/cm.

Results and conclusions: Our results show that time-varying magnetic field exposure increases transmembrane molecular transport and this uptake is greater for lower frequencies and larger number of pulses. Besides, the comparison shows that electroporation is more effective than pulsed magnetic field, but the observed uptake enhancement due to magnetic exposure is still considerable.

No MeSH data available.


Related in: MedlinePlus