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Biological Effects of 25 to 150 GHz Radiation After In Vitro Exposure of Human Fibroblasts: a Comparison of Experimental Results

  • Valeria Franchini
  • Silvio Ceccuzzi
  • Andrea Doria
  • Gian Piero Gallerano
  • Emilio Giovenale
  • Gian Luca Ravera
  • Andrea De Amicis
  • Stefania De Sanctis
  • Sara Di Cristofaro
  • Elisa Regalbuto
  • Elisa Coluzzi
  • Jessica Marinaccio
  • Antonella Sgura
  • Roberto Bei
  • Monica Benvenuto
  • Andrea Modesti
  • Laura Masuelli
  • Florigio Lista
Article

Abstract

In this paper, we present a comprehensive discussion of the results obtained after in vitro exposure of human fetal fibroblasts and human adult fibroblasts to pulsed radiation in a wide band between 100 and 150 GHz and to continuous wave radiation at 25 GHz. In order to assess potential effects of exposure, the genome integrity, cell cycle, cytological ultrastructure, and proteins expression were evaluated.

Keywords

Millimeter waves Terahertz Biological effects Non-ionizing radiation In vitro exposure Human primary cells Fibroblasts 

1 Introduction and Motivation of the Study

Millimeter waves and terahertz radiation are playing an increasing role in biophysics, biology, biochemistry, and biomedicine for their potential use in therapeutic and diagnostic applications [1]. Through the years, several issues have been addressed, from the understanding of the interaction mechanisms with biological systems to the study of millimeter waves/THz-induced effects [2], which has been systematically conducted during the last decade [3, 4]. In spite of this effort, the variety of radiation sources employed by different research groups worldwide [5] have also implied quite different characteristics in terms of the radiation spectral content and its temporal structure, which may in turn affect the response of biological systems.

A feature common to all studies on the interaction of millimeter waves/THz radiation with biological systems and on any potential human exposure is the strong absorption of water and the small penetration depth in hydrated tissues, which has gradually steered the research interest toward the investigation of effects on skin cells and peripheral blood.

Pioneering studies, carried out in the frame of the European project THz-BRIDGE [6], indeed addressed the exposure of human lymphocytes, membrane model systems, and epithelial cell cultures. Biological end-points were the alteration of membrane permeability of liposomes [7], the induction of genotoxicity in lymphocytes [8, 9], and the changes in cell activity, differentiation, and barrier function in keratinocytes and neural cells [10]. Few years later, a study addressed the exposure of primary human skin fibroblasts (HDF) and human keratinocyte cell lines (HaCaT) [11]. Another series of experiments addressed the determination of death thresholds in skin cells, and the identification of gene expression signatures [12].

In the frame of a collaboration between ENEA, the Scientific Department of Army Medical Center - Rome, the Department of Science University of “Roma Tre,” and the Department of Clinical Sciences and Translational Medicine - University of Rome “Tor Vergata”, a project was carried out to evaluate potential genotoxic effects associated with the “in vitro” exposure of living cells to high-frequency electromagnetic radiation, such as microwave and THz radiation. In this paper, we present a summary and a comprehensive discussion of the results obtained in the frame of this project, after in vitro exposures of human fetal fibroblasts (human fetal foreskin fibroblasts cell line - HFFF2) [13] and human adult fibroblasts (human dermal fibroblasts cell line - HDF) [14] to pulsed radiation in a wide band between 100 and 150 GHz and to continuous wave (CW) radiation at 25 GHz [15]. The observed differences between the effects of pulsed versus CW exposure are discussed in this paper.

2 Radiation Sources

Two radiation sources were employed in this study: an undulator-based free-electron laser (ENEA Compact-FEL) covering the spectral range from 100 to 150 GHz, and a continuous wave (CW) solid-state source tunable in the frequency range 18–40 GHz.

The ENEA Compact-FEL is driven by a microtron accelerator delivering 13 ps electron bunches with 4 A peak current at an electron energy of 2.3 MeV [16]. Due to the specific characteristics of the electron beam, the Compact-FEL radiation is composed by a “train” of micropulses, each 50 ps long, with 330 ps spacing between adjacent micropulses, as sketched in Fig. 1. The overall duration of the train (macropulse) is 4 μs. For the experiment described in this paper, macropulses were produced at a repetition rate of 2.5 Hz. The peculiar temporal structure of the emitted radiation allows the investigation of the effects of high peak power, in the kilowatt range, while maintaining a low average power, typically a few milliwatts, incident on the sample, thus avoiding heating effects.
Fig. 1

Time structure of the FEL pulses

The FEL spectrum consists of several lines within the emission band, spaced at 3-GHz intervals, corresponding to the period of the radio frequency driving the accelerator [16]. For the irradiation of fibroblasts, the Compact-FEL was operated in the so-called wide-bandwidth mode, with the emission showing a typical relative bandwidth of around 20% (Fig. 2).
Fig. 2

Fabry-Peròt interferogram of the Compact-FEL wide-bandwidth radiation (100–150 GHz)

The CW source is an yttrium iron garnet (YIG) oscillator (Microlambda Wireless, Inc. - MLOS-1840), providing 20 mW output power in the spectral range between 18 and 40 GHz. In this study, the source was operated at a fixed frequency of 25 GHz.

3 Biological Targets

Due to the shallow penetration depth of millimeter waves/THz radiation in hydrated tissues, the absorption during any potential human exposure is located in the skin, which is the primary tissue target of non-ionizing electromagnetic radiation [2, 17]. More specifically, fibroblasts are particularly important in exposure studies since they are the most common cells of connective tissue in animals. They synthesize the extracellular matrix and collagen and play a critical role in wound healing. We have therefore chosen human fibroblasts as a cellular model and have investigated biological effects on HFFF2 and HDF cells in order to evaluate possible different responses according to the different developmental ages.

Both HFFF2 and HDF were cultured in DMEM medium (Euroclone) supplemented with 10% fetal bovine serum (Euroclone), 1% 2 mM l-glutamine and 1% penicillin/streptomycin (Gibco). For adult cell cultures, the medium was supplemented also with 1% non-essential amino acids (Euroclone). Cell cultures were grown incubated at 37 °C in humidified atmosphere, at 5% CO2. Twenty-four hours before millimeter wave/THz exposure, cells were seeded into 6-cm-diameter polystyrene Petri dishes (Corning 3295), in 5 ml of medium at the density of 2–2.5 × 105 cells. The thickness of the culture medium in the Petri dish was measured to be 0.21 cm. Cell cultures were exposed for 20 min using the exposure setups described below.

4 Exposure Setup

In vitro exposures of both HFFF2 and HDF were performed with radiation pulses in the band 100–150 GHz using the Compact-FEL described above. In addition to this, in order to investigate effects at lower frequencies, of potential interest in telecommunications, a CW exposure layout was also set up employing the YIG source described above. Based on currently allotted frequencies for telecommunications, the frequency of 25 GHz was chosen within the tuning range of the YIG source.

For both exposure setups, polystyrene resulted to be the Petri dish material with the lowest absorption in the whole range from 25 to 150 GHz. An optimal irradiation area was determined in order to get a uniform power density at the sample surface. A diameter of the Petri of 6 cm was found to be the best choice to perform the irradiation. Since the fibroblast cells form a thin layer adherent to the bottom of the Petri dish, the irradiation was performed from the bottom of the Petri so as to avoid the shielding effect of the culture medium contained in the Petri, as sketched in Fig. 3. We can approximately assume that the thickness of the fibroblast layer in all experiments was ΔHF~10 μm.
Fig. 3

Sketch of the Petri dish

For the 100–150 GHz exposure, the linearly polarized FEL radiation was transported to the exposure setup by means of a millimeter wave transmission line composed of a copper light pipe with a 25-mm clear aperture and appropriate delivery optics. A specific THz delivery system (TDS) was designed and built to provide the necessary expansion of the THz beam needed to match the area of the Petri dish, which was directly placed on top of the TDS (Fig. 4a). The geometry of the TDS is shown in Fig. 4b.
Fig. 4

a Photo of the 150 GHz exposure setup. b Drawing of the TDS from reference [13]

The power distribution at the end of the copper light pipe was measured by means of a pyroelectric array (Spiricon, Pyrocam III), as shown in Fig. 5a. The transverse profile measured along the external diameter at the output of the TDS is shown in Fig. 5b. A comparison with the theoretical Gaussian beam profile used to optimize the TDS design is also shown in Fig. 5b.
Fig. 5

Measured power distribution at a end of the copper light pipe—TDS input; b TDS output (bars: exp. data; continuous line: Gaussian profile)

The 25 GHz exposure setup is sketched in Fig. 6a. It consists of a horn antenna, fed by a double-ridge rectangular waveguide providing operation on the linearly polarized fundamental mode. The antenna with aperture of 35 × 28 mm2 is placed inside a metallic cylinder at a distance h = 5.65 cm from the top plate aperture and is aligned with its axis as shown in Fig. 6b. As in the 100–150 GHz setup, the Petri dish containing the biological sample is positioned on the aperture of the cylinder. A second pyramidal horn antenna and a calibrated Schottky diode, placed above the Petri dish, allow to detect the incident power before irradiation and during the exposure (Fig. 6c). The microwave setup has been characterized without the Petri dish by measuring the transmission coefficient S21 from the source to the receiving horn with a vector network analyzer. With this parameter, the transmitted power PT has been derived from the power PR measured by the calibrated diode as PT = PR/|S21|2 and found in agreement with the calibration data provided by the YIG oscillator manufacturer. This value can be reliably considered equal to the exposure power since, according to simulations, transmission losses from the YIG source to the Petri dish are negligible.
Fig. 6

Layout of the exposure setup: a Schematic view (1) YIG source, (2) rigid coaxial cable, (3) pyramidal horn, (4) Petri dish, (5) culture medium. b Detail of the setup showing the position of the Petri. c Photo of the exposure setup: from left to right, one can observe the YIG oscillator control unit, the Petri placed on top of the exposure setup, and the “sham exposed” sample on the right of the YIG oscillator

To provide irradiation as uniform as possible of the fibroblast cells adherent to the bottom of the Petri dish, the setup was modeled using CST Microwave Studio (CST-MS), following the guidelines given in [18], and Ansys’s High Frequency Structure Simulator (HFSS) software. The predicted intensity of the radiated electric field was validated against measurements of the field components orthogonal to the beam axis. These measurements were carried out with a waveguide probe and a Schottky diode by scanning an area of 8 × 8 cm2 on 30 different planes ranging from 0.1 to 3 cm above the cylinder aperture. A benchmark with the predictions from CST-MS and HFSS is shown in Fig. 7a.
Fig. 7

a Co- (top) and cross- (bottom) polar components of the electric field at 25 GHz, taken 2.3 cm above the aperture of the metallic cylinder. b SAR distribution on the cell layer at the bottom of the Petri at a distance h = 5.65 cm, setting the following HFSS parameters for a layer of cells with thickness 10 μm: voxel size = 0.2 and mass of tissue = 0.001

After the validation of simulation results, the polystyrene Petri dish containing the biological sample was modeled as described in [15]. The model included a thin layer of cells having thickness of 10 μm, adherent to the bottom of the Petri dish, covered by 5 ml of culture medium with the remaining space air. HFSS and CST-MS analyses were carried out using the material properties reported in Table 1.
Table 1

Material properties at 25 GHz for HFSS and CST-MS analyses: dielectric constant εr; conductivity σ (S/m); loss tangent tan δ, density ρ (kg/m3)

 

ε r

σ (S/m)

tan δ

ρ (kg/m3)

Vacuum (air)

1

0

 

0

Aluminum

1

3.8 × 107

 

2689

Polystyrene

2.54

4.24 × 10−4

1.2 × 10−4

1000

Distilled water @ 24 °C

31.42

48.38

1.0949

1000

Distilled water @ 37 °C

39.93

48.00

0.8547

1000

Tissue cells

20.20

24.20

0.8517

1000

An average specific absorption ratio (SAR) of about 20 mW/g was calculated according to the simple model described in [13]. The corresponding distribution of the SAR on the sample, computed with the HFSS code assuming an input power of 20 mW at 25 GHz, is shown in Fig. 7b.

In both setups, for each irradiation experiment, an unexposed sample, subjected to the same environmental conditions apart from the impinging radiation, was placed in the same working area and defined as “sham” sample.

Temperature measurements were performed by using a FLIR camera for the 100–150 GHz setup [13]. In the case of the 25 GHz setup, they were performed by means of a miniaturized thermocouple temperature probe (Fluke type K) placed inside a Petri dish with the wire orthogonal to the electric field of the incident radiation. During the chosen 20-min irradiation time, both the “exposed” and “sham” samples asymptotically approached the room temperature within a temperature variation of approximately 0.3 °C for the 100–150 GHz exposure and 0.6 °C for the 25 GHz setup. In this latter case, the increment turned out to be due to the heat dissipated by the YIG DC electrical power in the YIG source itself, which is inherently located near the exposure setup.

5 End-points and Biological Assays

In order to assess potential effects of millimeter wave/THz exposure, we evaluated the genome integrity, cell cycle, cytological ultrastructure, and proteins expression in HFFF2 and HDF cells after radiation exposure. For each end-point, at least three experimental replicates were performed.

To evaluate the effects of radiation on cell cycle distribution of asynchronized log phase growing HFFF2 and HDF cells, fluorescence-activated cell sorting (FACS) analysis of DNA content was performed. Cells were incubated with propidium iodide that stains DNA and analyzed by flow cytometry using a FACSCalibur cytometer running CellQuest software. The fluorescence intensity of the stained nuclei correlates with the amount of DNA they contain and permits to examine distribution of cells in the different phases of the cycle.

The possible direct DNA damage was investigated using the comet assay and the H2AX phosphorylation foci analysis. Alkaline and neutral variants of the comet assay were performed to detect respectively single- and double-strand DNA breaks. The damage has been estimated as percentage of DNA contained in the tail of the comet-like cells after electrophoresis [19, 20]. Furthermore, we analyzed one of the earliest markers of DNA double-strand breaks, the phosphorylation of the histone variant H2AX, the so-called γ-H2AX. This phosphorylated form can be visualized as discrete foci using specific antibodies with fluorescent tags [19].

In order to evaluate possible chromosome alterations, we performed the micronuclei (MN)-CREST assay. Micronuclei are small nuclei in the cytoplasm formed by acentric fragments or whole chromosomes not included in the two daughter nuclei during mitosis [21]. The CREST immunofluorescent technique, marking the centromere of all chromosomes, allows to identify the origin of the micronucleus. The presence (CREST-positive MN) or absence (CREST-negative MN) of the fluorescent signal inside the micronucleus indicates respectively an entire chromosome or a fragment. In the cytoplasm, the presence of a positive MN micronucleus corresponds to a chromosome that was not incorporated into one of the two daughter nuclei during mitosis (chromosome loss) due to a failure of mitotic spindle or to complex chromosomal configurations during anaphase.

We further assessed chromosome malsegregation induction in the exposed cells during mitosis analyzing the distribution between the two daughter nuclei of three homologous pairs (chromosomes 4, 10, and 17) by using centromeric probes labeled with three different fluorescent dyes. This phenomenon consists in an unequal division of the number of chromosomes in the two daughter cells during mitosis with one of the daughter nuclei lacking a chromosome copy and the other with an extra copy. Malsegregation events are due to the failure of homologous chromosomes on the metaphase plate during cell division. Chromosome loss and chromosome malsegregation are the main mechanisms involved in the induction of aneuploidy, which defines the alteration of cell normal chromosomes number.

Since the telomere is a functional structure involved in chromosomal stability and correct chromosome segregation [22], we analyzed the telomere modulation by Q-FISH to assess its possible role in the observed chromosomal instability.

The expression of heat shock and pro-survival signaling proteins has been evaluated by Western blot analysis. This technique allows to identify a target protein recognized by a specific antibody from a complex mixture of proteins. The target protein is first separated by gel electrophoresis according to its molecular weight and then transferred to a nitrocellulose membrane. The immune complexes are visualized by chemiluminescence. The intensity of the specific band correlates with its amount.

Ultrastructural analysis was performed to detect morphological cell changes after radiation exposure. This analysis consists in the observation of ultrathin section of cells by using an electron microscopy to examine cellular structures and organelles.

6 Comparison of Exposure Results

The results of the analyses performed on fetal and adult fibroblasts exposed to 100–150 GHz radiation suggest that this frequency does not induce direct DNA damage but indirect effects leading to aneuploidy.

Comet assay and γ-H2AX foci analysis evidenced no differences between sham and exposed cells, suggesting no DNA damage induced by 100–150 GHz. These results are supported also by the frequency of CREST-negative MN, indicating chromosome fragments, which showed no difference between sham and irradiated cells. On the other hand, significant increase of CREST-positive MN frequency, showing chromosome loss, was observed. This result suggests induction of aneuploidy associated to radiation exposure (Fig. 8a, b). The aneugenic effect was also observed by the analysis of non-disjunction events showing an increase of total non-disjunction in irradiated samples with respect to the control ones. Telomere length analysis showed no significant modulation after exposure, suggesting that this structure is not involved in the observed malsegregation.
Fig. 8

MN-CREST analysis: a and b The results of MN-CREST analysis on fetal and adult cells exposed to 100–150 GHz; c and d The results of MN-CREST analysis on fetal and adult fibroblasts exposed to 25 GHz. Bars indicate the standard error. *p < 0.05; **p < 0.01; ***p < 0.001 by χ2 test

The FACS analysis showed that the progression through the cell cycle was not affected by the 100–150 GHz irradiation both in adult and in fetal fibroblasts. Further, no modulation of the expression of heat shock and pro-survival signaling proteins, such as NF-kB, ERK1/2, and AKT, was observed after radiation exposure. In addition, markers of apoptosis activation, i.e., PARP-1 cleavage or differential expression of proapoptotic proteins, have not been modulated in irradiated compared to control cells. Similarly, no differences in the expression of cytoskeleton proteins such as actin and tubulin have been observed in irradiated as compared to control cells, both in adult and in fetal fibroblasts.

Similarly, the absence of direct DNA damage and the presence of aneuploidy effect were observed in both fetal and adult fibroblasts exposed to 25 GHz CW radiation. Indeed, comet assay, γ-H2AX foci, and CREST-negative MN frequency indicated no increase of DNA breakage after in vitro exposure.

Conversely, exposed cells showed a significant increase of CREST-positive MN frequency (Fig. 8c, d) and non-disjunction events indicating induction of aneuploidy associated to radiation exposure.

Telomere was not modulated after exposure and FACS analysis showed that the progression through the cell cycle was not affected by the 25 GHz radiation. We also found no modulation of the expression of heat shock and pro-survival signaling proteins after radiation exposure at this frequency.

For morphological analysis, irradiated cells were analyzed by an inverted microscope and compared to control cells. No morphological differences were found between control and irradiated cells, both in adult and in fetal fibroblasts. The results from the ultrastructural analysis were comparable between adult and fetal fibroblasts. The ultrastructural analysis showed a substantial increase of the polymerization of thin and intermediate filaments, below the plasma membrane and in the cytoplasm of cells exposed to 100–150 GHz pulsed radiation and analyzed 1 h after irradiation both in adult and in fetal fibroblasts (Fig. 9). In addition, a slight increase in primary and secondary lysosomes and the presence of some vacuoles were observed. Pinocytotic vesicles were detected below the plasma membrane. The ultrastructural analysis of cells 48 h after exposure does not reveal any difference between exposed and sham cells except for a slight increase of the polymerization of cytoskeletal filaments [13, 14]. These data suggest that the morphological changes revealed immediately after exposure were transitory. On the contrary, cells exposed to 25 GHz CW radiation showed no differences between exposed and sham cells and demonstrated a normal polymerization of cytoskeleton filaments as previously described [15].
Fig. 9

Ultrastructural analysis on 100–150 GHz irradiated cells. In the upper section, HFFF2 cells: a sham and b 1 h after exposure. In the lower section, HDF cells: c sham and d 1 h after exposure. Arrows show the altered polymerization of cytoskeleton filaments. N, nucleus; m, mitochondrion; ER, endoplasmic reticulum

7 Discussion and Perspectives

Biological assays performed on fibroblasts exposed to 100–150 GHz pulsed and 25 GHz CW radiation suggest that these frequencies can induce aneuploidy by chromosome loss and non-disjunction events. This effect was observed in both cell lines without great differences between fetal and adult fibroblasts. Since an altered polymerization of thin filaments in the cells was observed after irradiation at 100–150 GHz, the induction of aneuploidy could be due to a modified crosstalk between the spindle structure and the mitotic cortex or to the influence exerted on the mitotic apparatus by the relatively high electric field of the pulsed electromagnetic radiation. The normal polymerization of thin filaments in the cells after 25 GHz CW in vitro exposure suggests a different mechanism involved in the aneuploidy. In this case, the low electric field associated with CW exposure should not exert a significant influence on the spindle, while it is possible to hypothesize the alteration of one of the target of molecular events involved in the attachment of microtubules to chromosomal kinetochores.

Former studies carried out at ENEA-Frascati in the frame of the European project THz-BRIDGE indeed showed that short pulses of terahertz radiation generated by the Compact-FEL can yield a peak electric field greater than 2 kV/cm when the THz beam is focused to a spot size of about 0.5 cm2 at the sample. This relatively high value of the field amplitude is capable of inducing a voltage drop across a lipid bilayer, which cannot be considered completely negligible when compared to the natural membrane potential. The question then arises if rapidly oscillating short electromagnetic radiation pulses can be demodulated or “rectified” by biological systems. Interesting effects on the permeability of model membranes were observed on carbonic anhydrase (CA) loaded liposomes irradiated at 130 GHz for different values of the peak electric field and modulation conditions [7].

Other groups have shown that nanosecond pulsed electric fields greater than 20 kV/cm can penetrate in the interior of tumor cells and induce self-destruction [23]. In a similar way, bursts of electromagnetic radiation could be used to reach specific cells or to trigger the release of pharmaceutical drugs at a desired site. Comparative studies of pulsed electric fields and pulsed electromagnetic radiation under similar amplitude and duration condition would help to clarify the issue of signal demodulation in biological systems and may provide a unifying view of these phenomena [24]. A systematic investigation of the dependence of any effect on the above parameters and on the carrier frequency may prove to be crucial in the development of new diagnostic and therapeutic tools.

Recently, scientific attention has been focused on the identification of possible sensitive genes that change their expression profile after radiation exposure. The most used methodologies to study gene expression are microarray technology and the real-time PCR, techniques that imply the analysis of only preselected known genes. An innovative approach, based on the next-generation sequencing technology, permits to analyze the whole transcriptome, overcoming the limitation of previous techniques. This emerging and very promising methodology for the identification of new sensitive genes might contribute to clarify the biological pathways in response to non-ionizing radiation. We are currently investigating the biological response of cells exposed to 25 GHz radiation using the innovative NGS technology with the RNA-seq protocol and this will be object of a future work. To date, few data are available on the transcriptional response of cells exposed to MW radiation [25, 26, 27], although different frequencies, exposure duration, and cell lines have been used.

Finally, the variety of THz sources, detectors, components, and systems that are now available has also led to a high degree of interdisciplinary expertise in terahertz applications, which in turn can benefit from the cross-linking of the various fields. As an example, imaging devices originally developed for biological and environmental studies turned out to be an invaluable diagnostic tool in art conservation, which in turn provided new questions and new problems to be tackled in the understanding of biological degradation of work of arts. Similarly, safety issues of millimeter wave and terahertz radiation will be crucial in the implementation of 5G devices and in the development of active imaging systems for airport security.

Notes

Acknowledgements

We gratefully acknowledge the technical support of M. Aquilini, E. Campana, S. Di Giovenale, A. Fastelli, P. Petrolini, and B. Raspante in the design and realization of the exposure setup as well as their skillful assistance during the irradiation experiments.

Funding Information

This work was supported by the Italian Ministry of Defence, SEGREDIFESA/DNA – 5° Department of Technological Innovation (GREAM project).

References

  1. 1.
    M.-O. Mattsson, O. Zeni, M. Simko, Is there a biological basis for therapeutic applications of millimetre waves and THz waves?, J Infrared Milli Terahz Waves (this issue) Google Scholar
  2. 2.
    G.J. Wilmink, J.E.J Grund, Current state of research on biological effects of terahertz radiation, J Infrared Milli Terahz Waves; 32, 1074–1122 (2011)CrossRefGoogle Scholar
  3. 3.
    A. Ramundo Orlando, G.P. Gallerano, Terahertz Radiation Effects and Biological Applications, J Infrared Milli Terahz Waves 30, 1308–1318 (2009)Google Scholar
  4. 4.
    H. Hintzsche, C. Jastrow, T. Kleine-Ostmann, U. Kärst, T. Schrader, H. Stopper, Terahertz electromagnetic fields (0.106 THz) do not induce manifest genomic damage in vitro, PLoS One; 7: e46397 (2012)CrossRefGoogle Scholar
  5. 5.
    P. H. Siegel, Terahertz Technology in Biology and Medicine, IEEE Trans MW Theory and Tech 52, 2438–2447 (2004)CrossRefGoogle Scholar
  6. 6.
    G.P. Gallerano; E. Grosse, R. Korenstein, M. Dressel, W. Mantele, M.R. Scarfi, A.C. Cefalas, P. Taday, R.H. Clothier, P. Jepsen, THz-BRIDGE: a European project for the study of the interaction of terahertz radiation with biological systems, Proc. of the Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics Page(s): 817–818 (2004);  https://doi.org/10.1109/ICIMW.2004.1422345
  7. 7.
    A. Ramundo-Orlando, G.P. Gallerano, P. Stano, A. Doria, E. Giovenale, G. Messina, M. D’Arienzo, I. Spassovsky, Permeability changes of cationic liposomes loading carbonic anhydrase induced by 130 GHz pulsed radiation, Bioelectromagnetics 28, 587–598 (2007)CrossRefGoogle Scholar
  8. 8.
    O. Zeni, G.P. Gallerano, A. Perrotta, M. Romanò, A. Sannino, M. Sarti, M. D’Arienzo, A. Doria, E. Giovenale, A. Lai, G. Messina and M.R. Scarfì, Cytogenetic Observations in human peripheral blood leukocytes following in vitro exposure to THz radiation: A pilot study Health Phys. 92(4) 349–357 (2007)CrossRefGoogle Scholar
  9. 9.
    A. Korenstein-Ilan et al., Terahertz radiation increases genomic instability in human lymphocytes Radiation Research 170(2) 224­234 (2008)CrossRefGoogle Scholar
  10. 10.
    R.H. Clothier, N. Bourne, Effects of THz exposure on human primary keratinocyte differentiation and viability, Journal of Biological Physics 29, 179 (2003)CrossRefGoogle Scholar
  11. 11.
    H. Hintzsche, C. Jastrow, B. Heinen, K. Baaske, T. Kleine-Ostmann, M. Schwerdtfeger, M.K.Shakfa, U. Kärst, M. Koch, T.Schrader, H. Stopper, Terahertz radiation at 0.380 THz and 2.520 THz does not lead to DNA damage in skin cells in vitro, Radiat Res. 179, 38–45 (2013)CrossRefGoogle Scholar
  12. 12.
    Wilmink, G.J., et al. Determination of death thresholds and identification of terahertz (THz)-specific gene expression signatures. in Optical Interactions with Tissues and Cells XXI. 2010: SPIE. 7562: pp.75620K–75620K-8Google Scholar
  13. 13.
    A. De Amicis, S. De Sanctis, S. Di Cristofaro, V. Franchini, F. Lista, E. Regalbuto, E. Giovenale, G.P. Gallerano, P. Nenzi, R. Bei, M. Fantini, M. Benvenuto, L. Masuelli, E. Coluzzi, C. Cicia, A. Sgura, Biological effects of in vitro THz radiation exposure in human foetal fibroblasts, Mutation Research (2015) 793: 150–160CrossRefGoogle Scholar
  14. 14.
    V. Franchini, S. De Sanctis, J. Marinaccio, A. De Amicis, E. Coluzzi, S. Di Cristofaro, F. Lista, E. Regalbuto, A. Doria, E. Giovenale, G.P. Gallerano, R. Bei, M. Benvenuto, L. Masuelli, I. Udroiu, A. Sgura, Effect of 0.15 THz radiation on genome integrity of adult fibroblasts, Environmental and Molecular Mutagenesis, 2018 Mar 30  https://doi.org/10.1002/em.22192
  15. 15.
    V. Franchini, E. Regalbuto, A. De Amicis, S. De Sanctis, S. Di Cristofaro, E. Coluzzi, J. Marinaccio, A. Sgura, S. Ceccuzzi, A. Doria, G.P. Gallerano, E. Giovenale, G.L. Ravera, R. Bei, M. Benvenuto, A. Modesti, L. Masuelli, F. Lista, Genotoxic Effects In Human Fibroblasts Exposed To Microwave Radiation, Health Physics. Health Physics: July 2018 - Volume 115 - Issue 1 - p 126–139,  https://doi.org/10.1097/HP.0000000000000871
  16. 16.
    G.P. Gallerano, A. Doria, E. Giovenale, I. Spassovsky, High power THz sources and applications at ENEA-Frascati, J Infrared Milli Terahz Waves 35, 17–24 (2014)CrossRefGoogle Scholar
  17. 17.
    M. Lippmann, B.S. Cohen, R.B. Schlesinger, Environmental Health Science: Recognition, Evaluation and Control of Chemical and Physical Health Hazards Oxford University Press (2003)Google Scholar
  18. 18.
    T. Kleine-Ostman et al., Field Exposure and Dosimetry in the THz Frequency Range, IEEE Trans-TST, 4, pp.12–25 (2014)Google Scholar
  19. 19.
    L. Vershaeve, J. Juutilainen, I. Lagroye, J. Miyakoshi, R. Saunders, R. de Seze, T. Tenforde, E. van Rongen, B. Veyret. and Z. Xu, In vitro and in vivo genotoxicity of radiofrequency fields, Mutat Res 705(3): 252–68 (2010)CrossRefGoogle Scholar
  20. 20.
    A. Azqueta, K.B. Gutzkov, C.C. Priestley, S. Meier, J.S. Walker, G. Brunborg, A.R. Collins, A comparative performance test of standard, medium- and high-throughput comet assay, Toxicology in Vitro 27(2): 768–773 (2013)CrossRefGoogle Scholar
  21. 21.
    F. Degrassi, C. Tanzarella, L.A. Ierardi, J. Zima, A. Cappai, A. Lascialfari, F. Allegra, M. Cristaldi, CREST staining of micronuclei from free-living rodents to detect enviromental contamination in situ, Mutagenesis 14(4): 391–396 (1999)CrossRefGoogle Scholar
  22. 22.
    A. Sgura and D. Cimini, Telomeres and chromosomes segregation in Telomeres: Function, Shortening and Lengthening. Editor: Leonardo Mancini Nova Science Publishers, Inc. (2009)Google Scholar
  23. 23.
    R. Nuccitelli et al., Nanosecond Pulsed electric fields cause melanomas to selfdestruct, Biochemical and Biophysical Research Communications (BBRC) 343, 351 (2006)CrossRefGoogle Scholar
  24. 24.
    P. Lukes, H. Akiyama, C. Jiang, A. Doria, G.P. Gallerano, A. Ramundo-Orlando, S. Romeo, M.R. Scarfì, O. Zeni, Special Electromagnetic Agents: From Cold Plasma to Pulsed Electromagnetic Radiation in Akiyama H., Heller R. (Eds) Bioelectrics, 109–154 Springer, Tokyo (2017)CrossRefGoogle Scholar
  25. 25.
    D. Remondini, R. Nylund, J. Reivinen, F. Poulletier de Gannes, B. Veyret, I. Lagroye, E. Haro, M.A. Trillo, M. Capri, C. Franceschi, K. Schlatterer, R. Gminski, R. Fitzner, R. Tauber, J. Schuderer, N. Kuster, D. Leszczynski, F. Bersani, C. Maercker, Gene expression changes in human cells after exposure to mobile phone microwaves., Proteomics. 2006 Sep; 6(17):4745–54.CrossRefGoogle Scholar
  26. 26.
    T. Sakurai, T. Kiyokawa, E. Narita, Y. Suzuki, M. Taki, J. Miyakoshi,Analysis of gene expression in a human-derived glial cell line exposed to 2.45 GHz continuous radiofrequency electromagnetic fields., J Radiat Res. 2011;52(2):185–92.CrossRefGoogle Scholar
  27. 27.
    D. Habauzit, C. Le Quement, M. Zhadobov, C. Martin, M. Aubry, R. Sauleau, Y. Le Drean,Transcriptome Analysis Reveals the Contribution of Thermal and the Specific Effects in Cellular Response to Millimeter Wave Exposure., PlosOne (2014) 9(10): e109435.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • Valeria Franchini
    • 1
  • Silvio Ceccuzzi
    • 2
  • Andrea Doria
    • 2
  • Gian Piero Gallerano
    • 2
  • Emilio Giovenale
    • 2
  • Gian Luca Ravera
    • 2
  • Andrea De Amicis
    • 1
  • Stefania De Sanctis
    • 1
  • Sara Di Cristofaro
    • 1
  • Elisa Regalbuto
    • 1
    • 3
  • Elisa Coluzzi
    • 3
  • Jessica Marinaccio
    • 3
  • Antonella Sgura
    • 3
  • Roberto Bei
    • 4
  • Monica Benvenuto
    • 4
  • Andrea Modesti
    • 4
  • Laura Masuelli
    • 5
  • Florigio Lista
    • 1
  1. 1.Scientific Department of Army Medical Center of RomeRomeItaly
  2. 2.ENEA, Fusion and Nuclear Safety DepartmentRomaItaly
  3. 3.Department of ScienceUniversity of Rome “Roma Tre”RomeItaly
  4. 4.Department of Clinical Sciences and Translational MedicineUniversity of Rome “Tor Vergata”RomeItaly
  5. 5.Department of Experimental MedicineUniversity of Rome “La Sapienza”RomeItaly

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