Induced movements of giant vesicles by millimeter wave radiation

Abstract

Our previous study of interaction between low intensity radiation at 53.37GHz and cell-size system - such as giant vesicles - indicated that a vectorial movement of vesicles was induced. This effect among others, i.e. elongation, induced diffusion of fluorescent dye di-8-ANEPPS, and increased attractions between vesicles was attributed to the action of the field on charged and dipolar residues located at the membrane-water interface. In an attempt to improve the understanding on how millimeter wave radiation (MMW) can induce this movement we report here a real time evaluation of changes induced on the movement of giant vesicles. Direct optical observations of vesicles subjected to irradiation enabled the monitoring in real time of the response of vesicles. Changes of the direction of vesicle movement are demonstrated, which occur only during irradiation with a "switch on" of the effect. This MMW-induced effect was observed at a larger extent on giant vesicles prepared with negatively charged phospholipids. The monitoring of induced-by-irradiation temperature variation and numerical dosimetry indicate that the observed effects in vesicle movement cannot be attributed to local heating.

Picosecond and Terahertz Perturbation of Interfacial Water and Electropermeabilization of Biological Membranes

“…Where responses are observed (Ramundo-Orlando and Gallerano 2009), some appear to be associated with temperature increases (Wilmink et al 2011), but others seem to be caused by direct, temperature-independent interactions of electric fields with biological processes (Titova et al 2013a; Titova et al 2013b). Millimeter waves, an electromagnetic regime that may be considered to overlap with terahertz radiation, have also been reported to affect biological systems (Ramundo-Orlando et al 2007; Kim et al 2013; Albini et al 2014; Romanenko et al 2014), and these phenomena may be related. Because effects from both picosecond pulses and terahertz radiation imply electric-field-driven biomolecular rearrangements on the picosecond time scale, the mechanisms for the two sets of phenomena are likely to be related, and it may be beneficial to consider them together.…”

The interaction between electromagnetic fields at megahertz, gigahertz and terahertz frequencies with cells, tissues and organisms: risks and potential

“…Thus, the effect of MMW on neurons is a result of coupling with another membrane-related mechanism. Studies by Ramundo-Orlando et al [ 70 , 78 – 81 ] showed increased permeability in membranes of artificial liposomes upon the application MMW–terahertz radiation. Membranes loaded with carbonic anhydrase liposomes subjected to 53.37 GHz 0.1 mW cm −2 radiation exhibited an enhanced carbonic anhydrase reaction rate when p -nitrophenyl acetate was applied [ 79 , 82 ].…”