The influence of millimeter waves on the physical properties of large and giant unilamellar vesicles

Abstract

Exposure of cell membranes to an electromagnetic field (EMF) in the millimeter wave band (30-300 GHz) can produce a variety of responses. Further, many of the vibrational modes in complex biomolecules fall in the 1-100 GHz range. In addition to fundamental scientific interest, this may have applications in the development of diagnostic and therapeutic medical applications. In the present work, lipid vesicles of different size were used to study the effects of exposure to radiation at 52-72 GHz, with incident power densities (IPD) of 0.0035-0.010 mW/cm 2 , on the chemical-physical properties of cell membranes. Large unilamellar vesicles (LUVs) were used to study the effect of the radiation on the physical stability of vesicles by dynamic light scattering. An inhibition of the aging processes (Ostwald ripening), which usually occur in these vesicles because of their thermodynamic instability, resulted. Giant unilamellar vesicles (GUVs) were used to study the effect of the radiation on membrane water permeability under osmotic stress by phase contrast microscopy. In this case, a decrease in the water membrane permeability of the irradiated samples was observed. We advance the hypothesis that both the above effects may be explained in terms of a change of the polarization states of water induced by the radiation, which causes a partial dehydration of the membrane and consequently a greater packing density (increased membrane rigidity). Electronic supplementary materialThe online version of this article

Effects of millimeter wave irradiation and equivalent thermal heating on the activity of individual neurons in the leech ganglion

“…We propose two (potentially interconnected) consequences of the MMW-induced disorientation of the water dipoles at the hydration layer of the neuronal plasma membrane before their rotational energy is thermalized and dissipated throughout the tissue: 1 ) altered fluidity and/or structure of the transmembrane phospholipids ( Beneduci 2008 ; Davidson et al 2013 ; Ramundo-Orlando 2010 ) via an efficient energy transfer from the hydration layer to the membrane phospholipids ( Mashaghi et al 2012 ); and 2 ) reduced gigahertz-range dielectric permittivity and capacitance of the plasma membrane ( Blum and Henderson 1981 ; Grodsky 1976 ; Sheppard et al 2008 ). Initial support for these hypotheses comes from a theoretical model describing the interaction of MMWs with biological membranes ( Beneduci et al 2014 ) and from experimental studies on biomembranes ( Beneduci et al 2012 , 2013 ; Cosentino et al 2013 ). We hope to evaluate these proposed mechanisms for the observed MMW effects on neuronal activity in future studies.…”

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

“…It is unlikely that the endogenous voltage-dependent or potential creating mechanisms would directly interact with the exogenous high-frequency stimulus. Adair's analysis of MMW interaction with voltage-dependent transmembrane channels showed that alterations in the probability of channels opening would be very low [ 70 ]. Also, the change in membrane potential is directly proportional to the intensity of the external stimulus and inversely proportional to the frequency.…”

“…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 ].…”

Recent Biophysical Issues About the Preparation of Solute-Filled Lipid Vesicles

“…Further investigation on the factors affecting this interesting behavior is needed. Among several possibilities, the formation of liposomes might perhaps be perturbed by electromagnetic waves in the radiofrequencies range (which have been shown to interact with liposomes [53]), to test whether the super-encapsulation is canceled or enhanced. A specific and yet unknown mechanism might be found.…”