Medical/biological study (experimental study)

The response of giant phospholipid vesicles to millimeter waves radiation med./bio.

By: Ramundo-Orlando A, Longo G, Cappelli M, Girasole M, Tarricone L, Beneduci A, Massa R

Published in: Biochim Biophys Acta Biomembr 2009; 1788 (7): 1497-1507

To study the effects of low-intensity millimeter waves at 53.37 GHz (considered as "therapeutic" frequency) on membrane model systems (giant vesicles).

Giant vesicles have a size in the micrometer range, i.e. are of cell-size, and could reflect the membrane properties and "behavior" that occur in the cell membrane.

vesicle "behavior": changes in vesicle geometry (i.e. elongation) and movement, induced diffusion of a fluorescent dye and increased attraction between vesicles

Exposure	Parameters
Exposure 1: 53.37 GHz Exposure duration: 30 s, 1 min, 2 min or 4 min	power: 39 mW electric field strength: 20 V/m (+/- 10 %) SAR: 0.1 W/kg minimum SAR: 0.5 W/kg maximum power density: 0.1 mW/cm²

Exposure source	horn antenna
Distance between exposed object and exposure source	8 cm
Setup	conocal horn antenna fixed above the samples so that the incident angle of the radiation was 45°
Sham exposure	A sham exposure was conducted.

Measurand	Value	Type	Method	Mass	Remarks
power	39 mW	-	-	-	-
electric field strength	20 V/m	-	measured	-	+/- 10 %
SAR	0.1 W/kg	minimum	calculated	-	-
SAR	0.5 W/kg	maximum	calculated	-	-
power density	0.1 mW/cm²	-	-	-	-

Exposed system:

vesicle "behaviour": changes in vesicle geometry (i.e. elongation) and movement, induced diffusion of a fluorescent dye and increased attraction between vesicles (light microscopy); temperature measurement in the suspensions

Investigated system:

Time of investigation:

The data showed physical changes of vesicles, i.e. elongation, induced diffusion of the fluorescent dye, and increased attractions between vesicles. These effects were reversible and occured only during irradiation. Since the average temperature change was very small the effects can not be attributed to thermal mechanisms.
The authors assume that the interaction of millimeter waves with lipid bilayer leads to changes at the membrane-water interface, where charged and dipolar residues of molecules are located.

Study character:

Mady MM et al. (2012): The influence of low power microwave on the properties of DPPC vesicles
Nicolaz CN et al. (2009): Absence of direct effect of low-power millimeter-wave radiation at 60.4 GHz on endoplasmic reticulum stress
Nicolaz CN et al. (2009): Study of narrow band millimeter-wave potential interactions with endoplasmic reticulum stress sensor genes
Aranda S et al. (2008): Morphological transitions of vesicles induced by alternating electric fields
Ramundo-Orlando A et al. (2007): Permeability changes induced by 130 GHz pulsed radiation on cationic liposomes loaded with carbonic anhydrase
Zhadobov M et al. (2006): Interactions between 60-GHz millimeter waves and artificial biological membranes: dependence on radiation parameters
Ramundo-Orlando A et al. (2004): Effects of 2.45 GHz microwave fields on liposomes entrapping glycoenzyme ascorbate oxidase: Evidence for oligosaccharide side chain involvement
Alekseev SI et al. (1995): Millimeter microwave effect on ion transport across lipid bilayer membranes
Ramundo-Orlando A et al. (1993): Enzymatic kinetic change of ascorbate oxidase loaded into liposomes induced by microwave fields exposure