The effect of terahertz radiation on clusterization of bovine serum albumin (BSA) molecules and on BSA binding with nickel, cobalt and cadmium ions is investigated by means of high performance liquid chromatography and EPR spectroscopy under variation of the concentration of molecular oxygen in solution. Irradiation is detected to remove steric hindrance for oxygen adsorption. The degree of nickel and cobalt ion binding with irradiated BSA samples is substantially higher than with non-irradiated ones, while for cadmium the binding degree is the same and rather low in both cases. The functional groups in BSA molecule participating in metal ion binding are revealed by means of semi-empirical simulation.

Significance: An increasing interest in the area of biological effects at exposure of tissues and cells to the terahertz (THz) radiation is driven by a rapid progress in THz biophotonics, observed during the past decades. Despite the attractiveness of THz technology for medical diagnosis and therapy, there is still quite limited knowledge about safe limits of THz exposure. Different modes of THz exposure of tissues and cells, including continuous-wave versus pulsed radiation, various powers, and number and duration of exposure cycles, ought to be systematically studied. Aim: We provide an overview of recent research results in the area of biological effects at exposure of tissues and cells to THz waves. Approach: We start with a brief overview of general features of the THz-wave-tissue interactions, as well as modern THz emitters, with an emphasis on those that are reliable for studying the biological effects of THz waves. Then, we consider three levels of biological system organization, at which the exposure effects are considered: (i) solutions of biological molecules; (ii) cultures of cells, individual cells, and cell structures; and (iii) entire organs or organisms; special attention is devoted to the cellular level. We distinguish thermal and nonthermal mechanisms of THz-wave-cell interactions and discuss a problem of adequate estimation of the THz biological effects' specificity. The problem of experimental data reproducibility, caused by rareness of the THz experimental setups and an absence of unitary protocols, is also considered. Results: The summarized data demonstrate the current stage of the research activity and knowledge about the THz exposure on living objects. Conclusions: This review helps the biomedical optics community to summarize up-to-date knowledge in the area of cell exposure to THz radiation, and paves the ways for the development of THz safety standards and THz therapeutic applications. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License.

This review discusses the current state of research concerning the effects of terahertz (THz) radiation on living cells in the context of biosafety of THz radiation for the human organism.

Terahertz (THz) radiation and related technologies are rapidly developed and find their application in different branches of science and technology, including medical diagnostics and therapy. This poses a problem of determining the safety limits of the human body exposure to THz radiation, which is closely related to a problem of biological activity of THz waves. Therefore, in this work, the current state of research in the area of THz radiation – cells interaction is overviewed.

This article presents a review of the literature data and our own data concerning the effects of terahertz radiation on the state of DNA, the chromosome, and the activity of genes in the cells of micro-organisms and eukaryotes. The phenotypical changes that accompany the irradiation of intact organisms are described. Mutagenic effects and epigenetic pathways of action are considered. Possible mechanisms of the nonthermal action of terahertz radiation are discussed. (C) 2017 Optical Society of America

An investigation into the effect of nonionizing terahertz radiation (0.1–10 THz) on living organisms is urgent due to the recent development of modern technologies employing such radiation. The aim of this study was to establish the impact of terahertz radiation on successive generations of fruit flies. The effects of terahertz radiation on the survival ability and lifespan of the Oregon-R strain of Drosophila melanogaster proved to be diverse: they were negative or neutral at early life stages and positive at late stages. The female flies exposed to the radiation showed increased survival rate during the second half of the life of imago. The males demonstrated low sensitivity to the radiation. There were no significant differences noted in the dynamics of maturation and total number of offspring between the female flies that were exposed to the radiation and those that were not. The results of the study practically did not depend on the sex and maturity stage of the oocytes irradiated.

Virgin fruit fly females and males were stressed by placement into a confined space without food for 3 h. Part of stressed flies were subjected to terahertz irradiation (0.1–2.2 THz) during 30 min. Life span of individual flies was evaluated. Terahertz radiation had some positive influence on male survival during the stage of monotonic decrease in flies number and negative effect during the stage of relatively stable number of flies. The survival of irradiated females on the stage of sharp decline in the number of flies was higher than in stressed and control females. Authors propose that terahertz radiation has an indirect effect on gene expression and signaling pathways which control the survival and life span of Drosophila.

Life span control is realized by the interaction of many genetic factors with the environment. Due to the development of modern technologies based on nonionized terahertz radiation (0.1–10 THz), the investigation of the influence of this radiation on living organisms is urgent. In our study, the effects of terahertz radiation on the survival and lifespan of the Oregon R line of Drosophila melanogaster were multidirectional, depending on the age of the insects. The terahertz effect on survival was negative or neutral in early life and positive in later life. In the drosophila response to terahertz radiation, sex differences were manifested. Males were not very sensitive to terahertz radiation. The survival of irradiated females increased significantly in the second half of the imago life. Irradiation of the drosophila did not significantly affect mean and maximal values of lifespan, but the gap between the values of the mean lifespans of males and females in this group of insects was increased. The mechanisms for the effects of terahertz radiation on survival and lifespan might be associated with changes in the cellular membrane, gene expression, and signaling pathways controlling these features.

Virgin fruit fly females were stressed by placement into a confined space without food for 2.5 hours. Some flies were subjected to terahertz radiation (0.1–2.2 THz) for the last 30 min. Then females were copulated with males. Offspring F1 from oocytes which were mature or immature at exposure (oviposition in 1–2 or 9–10 days after irradiation) was studied. Stress induces a rejection of the offspring maturation dynamics to imago from external control (offspring of flies which was maintained in standard conditions). In offsping from mature oocytes of irradiated flies the dynamics of male maturation to imago was different from internal control (offspring of stressed unirradiated flies). The number of imago males decreased. The dynamics of female maturation to imago coincides with laboratory control. In offsping from immature oocytes of irradiated flies the dynamics of female and male maturation and the number of flies were not significantly different from the internal control. It was concluded that only mature oocytes are sensitive to THz radiation influence.

The purpose of this investigation is the study of THz influence on female fruit fly fertility and offspring development dynamics. The material is virgin females Oregon R line. Flies (n = 200) were stressed by limited space without food during 2.5 hours. Some of flies (n = 100) were irradiated by THz radiation generator in frequency range 0.1 2.2 THz during 30 min. The results were compared with the offspring of laboratory control (n = 100). Objectively. Stress induces a rejection of offspring maturation dynamics to imago from laboratory control. THz radiation induces different effects. The dynamics of female maturation coincides with laboratory control. The number of imago males decreased. Conclusion. THz radiation causes a deviation from theoretically expected 1:1 gender ratio.

Effect of the preliminary irradiation of bovine serum albumin (BSA) in the terahertz spectral range on the conformation changes revealed with the help of EPR spectroscopy was investigated using the spin probing technique. The formation of the spin probe occurs directly in the aqueous solution of BSA from a nitrone compound (dihydropyrazine dioxide). It was shown that irradiation causes changes in the parameters of the EPR spectrum of the spin probe. An approach to linking the observed changes with the structural characteristics of reaction centres - the functional groups of amino acids comprising BSA - was outlined.

The exposure of albumin (transport protein of blood serum) to laser radiation with a frequency of 3.6 THz resulted in a change in the intensity of characteristic bands in UV absorption spectra and in circular dichroism spectra. These changes depend on the exposure duration and the laser radiation power and indicate conformational changes in protein molecules.

Облучение транспортного белка сыворотки крови альбумина лазерным излучением с частотой 3.6 ТГц привело к изменению интенсивности характерных полос в УФ спектрах поглощения и в спектрах кругового дихроизма. Эти изменения зависят от длительности облучения и мощности лазерного излучения и свидетельствуют о конформационных перестройках в молекулах белка.

The low intensive terahertz radiation induces changes in biological macromolecules conformation which affects of their functional properties. It can be used for testing of pathological modified macromolecules and for creation of new diagnostic methods.

Terahertz radiation affects on peptide optical properties and decreases a binding capacity of protein with native ligand. This indicates that terahertz radiation induces changes in peptide conformation.