Sensitivity of Neuroblastoma and Induced Neural Progenitor Cells to High-Intensity THz Radiation

Chernomyrdin N.V., Musina G.R., Nikitin P.V., Dolganova I.N., Kucheryavenko A.S., Alekseeva A.I., Wang Y., Xu D., Shi Q., Tuchin V.V., Zaytsev K.I.

Sitnikov D.S., Revkova V.A., Ilina I.V., Gurova S.A., Komarov P.S., Struleva E.V., Konoplyannikov M.A., Kalsin V.A., Baklaushev V.P.

The data is obtained on the effect of high-intensity pulses of terahertz (THz) radiation with a broad spectrum (0.2-3 THz) on cell cultures. We have evaluated the threshold exposure parameters of THz radiation causing genotoxic effects in fibroblasts. Phosphorylation of histone H2AX at Ser 139 (γH2AX) was chosen as a marker for genotoxicity and a quantitative estimation of γH2AX foci number in fibroblasts was performed after cell irradiation with THz pulses for 30 min. No genotoxic effects of THz radiation were observed in fibroblasts unless peak intensity and electric field strength exceeded 21 GW cm-2 and 2.8 MV cm-1 , respectively. In tumor cell lines (neuroblastoma (SK-N-BE (2)) and glioblastoma (U87)), exposure to THz pulses with peak intensity of 21 GW cm-2 for 30 min caused no morphological changes as well as no statistically significant increase in histone phosphorylation foci number.

Ovchinnikov A.V., Chefonov O.V., Agranat M.B., Shalaby M., Sitnikov D.S.

We present the results of experimental investigations of terahertz radiation generation conversion efficiency in an OH1 nonlinear organic crystal pumped by femtosecond laser pulses at 1240 nm wavelength. An influence of OH1 crystal thickness on the terahertz generation by optical rectification method was studied. It is shown that the optimal crystal thickness for the maximum conversion efficiency is 1 mm, which agrees with the previously made theoretical estimates.

Romeo S., Zeni O., Scarfì M., Poeta L., Lioi M., Sannino A.

In the last decades, experimental studies have been carried out to investigate the effects of radiofrequency (RF, 100 kHz–300 GHz) electromagnetic fields (EMF) exposure on the apoptotic process. As evidence-based critical evaluation of RF and apoptosis in vitro is lacking, we performed a scoping literature review with the aim of systematically mapping the research performed in this area and identifying gaps in knowledge. Eligible for inclusion were in vitro studies assessing apoptosis in mammalian cells exposed to RF-EMF, which met basic quality criteria (sham control, at least three independent experiments, appropriate dosimetry analysis and temperature monitoring). We conducted a systematic literature review and charted data in order to overview the main characteristics of included studies. From the 4362 papers retrieved with our search strategy, 121 were pertinent but, among them, only 42 met basic quality criteria. We pooled data with respect to exposure (frequency, exposure level and duration) and biological parameters (cell type, endpoint), and highlighted some qualitative trends with respect to the detection of significant effect of RF-EMF on the apoptotic process. We provided a qualitative picture of the evidence accumulated so far, and highlighted that the quality of experimental methodology still needs to be highly improved.

Amini T., Jahangiri F., Ameri Z., Hemmatian M.A.

Introduction: Terahertz (THz) waves with frequencies in the range of 0.1 to 10 THz are electromagnetic radiation with growing applications in various fields of science and technology. Attractive features of this radiation have brought out many novel possibilities for medical diagnostics and treatments with considerable advantages compared to other conventional methods. Methods: In this paper, we present a review of more recent reports on practical applications of THz radiation for diagnostic, biosensing and clinical treatments. The review includes the diagnosis of breast, skin, mouth, cervical, lungs, small intestine, prostate, colon, and stomach cancers, the evaluation of biomolecules, the detection of genetic mutations, the determination of burn depth, the diagnosis of tooth decay, diabetes, and emotional-psychological states, the evaluation of corneal water to diagnose visual diseases, and wound healing monitoring. Further, it embraces the use of THz therapy in reducing the size of the tumor, treating skin cancer, and healing burn wounds, cardiovascular disease, corneal epithelium, angina, and THz heating. Results: This review has emphasized the capabilities of THz waves as a novel tool for future clinical diagnostics and treatments. Conclusion: The paper provides a comprehensive understanding of the feasible potential application of THz waves for clinical purposes and its advantages in comparison with other conventional tools.

Zhao X., Zhang M., Liu Y., Liu H., Ren K., Xue Q., Zhang H., Zhi N., Wang W., Wu S.

Terahertz (THz) frequency occupies a large portion of the electromagnetic spectrum that is between the infrared and microwave regions. Recent advances in THz application have stimulated interests regarding the biological effects within this frequency range. In the current study, we report that irradiation with a single-frequency THz laser on mice cortical neuron cultures increases excitatory synaptic transmission and neuronal firing activities. Microarray assay reveals gene expression dynamics after THz exposure, which is consistent with morphology and electrophysiology results. Besides, certain schedule of THz irradiation inhibits the proliferation of oligodendrocyte precursor cells (OPCs) and promotes OPC differentiation. Of note, the myelination process is enhanced after THz exposure. In summary, our observations suggest that THz irradiation can modulate the functions of different neuronal cells, with different sensitivity to THz. These results provide important understanding of the mechanisms that govern THz interactions with nervous systems and suggest THz wave as a new strategy for neuromodulation.

Konoplyannikov M.A., Eremina A.S., Kargina Y.V., Le-Deygen I.M., Kharin A.Y., Bazylenko T.Y., Yusubalieva G.M., Revkova V.A., Matchuk O.N., Zamulaeva I.A., Abramova M.R., Kotova S.L., Timashev P.S., Baklaushev V.P., Timoshenko V.Y.

Mesoporous silicon nanoparticles loaded with salinomycin, a promising anticancer drug, were investigated as potential nanocontainers for cancer therapy. The drug loading and release were studied by means of the infrared spectroscopy, which revealed a gradual release of the drug with rate dependent on the mass ratio between the nanoparticles and salinomycin. In vitro studies revealed that the prepared nanoparticles loaded with salinomycin resulted in a notable cytotoxic effect on human glioblastoma cells, MCF-7 breast cancer cells and multidrug resistant MCF-7/MDR1 cells. In vivo experiments showed a strong suppression of the Lewis lung carcinoma tumor growth for 10–30 days after intraperitoneal administration of the nanocontainers. The obtained results indicate that salinomycin-loaded mesoporous silicon nanoparticles are prospective for mild chemotherapy of both primary cancer tumors and metastasis. The revealed efficiency against chemotherapy-resistant cancer stem cells and possibility of the intraperitoneal administration are very promising for further clinical applications of the prepared nanocontainers. • Mesoporous silicon nanoparticles are being investigated as nanocontainers for salinomycin. • The drug release is studied using infrared spectroscopy. • In vitro studies show a noticeable cytotoxic effect of nanocontainers. • Intraperitoneally administrated nanocontainers suppress the growth of a cancerous tumor in mice.

Nazarov M.M., Shcheglov P.A., Teplyakov V.V., Chashchin M.V., Mitrofanov A.V., Sidorov-Biryukov D.A., Panchenko V.Y., Zheltikov A.M.

We identify the physical factors that limit the terahertz (THz) yield of an optical rectification (OR) of ultrashort multiterawatt laser pulses in large-area quadratically nonlinear crystals. We show that the THz yield tends to slow its growth as a function of the laser driver energy, saturate, and eventually decrease as the laser beam picks up a spatiotemporal phase due to the intensity-dependent refraction of the OR crystal. We demonstrate that, with a careful management of the driver intensity aimed at keeping the nonlinear length larger than the coherence length, OR-based broadband THz generation in large-area lithium niobate (LN) crystals is energy-scalable, enabling an OR of multiterawatt laser pulses, yielding ∼10µJ/cm2 of THz output energy per unit crystal area. With a 27-fs, 10-TW, 800-nm Ti:sapphire laser output used as a driver for OR in large-area LN crystals, this approach is shown to provide a THz output with a pulse energy above 10 µJ and a bandwidth extending well beyond 6 THz, supporting single-cycle THz waveforms.

Sitnikov D.S., Ilina I.V., Revkova V.A., Rodionov S.A., Gurova S.A., Shatalova R.O., Kovalev A.V., Ovchinnikov A.V., Chefonov O.V., Konoplyannikov M.A., Kalsin V.A., Baklaushev V.P.

For the first time, the data have been obtained on the effects of high-intensity terahertz (THz) radiation (with the intensity of 30 GW/cm2, electric field strength of 3.5 MV/cm) on human skin fibroblasts. A quantitative estimation of the number of histone Н2АХ foci of phosphorylation was performed. The number of foci per cell was studied depending on the irradiation time, as well as on the THz pulse energy. The performed studies have shown that the appearance of the foci is not related to either the oxidative stress (the cells preserve their morphology, cytoskeleton structure, and the reactive oxygen species content does not exceed the control values), or the thermal effect of THz radiation. The prolonged irradiation of fibroblasts also did not result in a decrease of their proliferative index.

Sitnikov D.S., Pronkin A.A., Ilina I.V., Revkova V.A., Konoplyannikov M.A., Kalsin V.A., Baklaushev V.P.

Exposure of cells or biological tissues to high-power pulses of terahertz (THz) radiation leads to changes in a variety of intracellular processes. However, the role of heating effects due to strong absorption of THz radiation by water molecules still stays unclear. In this study, we performed numerical modelling in order to estimate the thermal impact on water of a single THz pulse as well as a series of THz pulses. A finite-element (FE) model that provides numerical solutions for the heat conduction equation is employed to compute the temperature increase. A simple expression for temperature estimation in the center of the spot of THz radiation is presented for given frequency and fluence of the THz pulse. It has been demonstrated that thermal effect is determined by either the average power of radiation or by the fluence of a single THz pulse depending on pulse repetition rate. Human dermal fibroblasts have been exposed to THz pulses (with an energy of $$15\,\upmu \hbox {J}$$ and repetition rate of 100 Hz) to estimate the thermal effect. Analysis of heat shock proteins expression has demonstrated no statistically significant difference ( $$p < 0.05$$ ) between control and experimental groups after 3 h of irradiation.

Cherkasova O.P., Serdyukov D.S., Nemova E.F., Ratushnyak A.S., Kucheryavenko A.S., Dolganova I.N., Xu G., Skorobogatiy M., Reshetov I.V., Timashev P.S., Spektor I.E., Zaytsev K.I., Tuchin V.V.

Abstract. 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.

Musina G.R., Chernomyrdin N.V., Gafarova E.R., Gavdush A.A., Shpichka A.J., Komandin G.A., Anzin V.B., Grebenik E.A., Kravchik M.V., Istranova E.V., Dolganova I.N., Zaytsev K.I., Timashev P.S.

In this paper, terahertz (THz) pulsed spectroscopy and solid immersion microscopy were applied to study interactions between water vapor and tissue scaffolds-the decellularized bovine pericardium (DBP) collagen matrices, in intact form, cross-linked with the glutaraldehyde or treated by plasma. The water-absorbing properties of biomaterials are prognostic for future cell-mediated reactions of the recipient tissue with the scaffold. Complex dielectric permittivity of DBPs was measured in the 0.4-2.0 THz frequency range, while the samples were first dehydrated and then exposed to water vapor atmosphere with 80.0 ± 5.0% relative humidity. These THz dielectric measurements of DBPs and the results of their weighting allowed to estimate the adsorption time constants, an increase of tissue mass, as well as dispersion of these parameters. During the adsorption process, changes in the DBPs' dielectric permittivity feature an exponential character, with the typical time constant of =8-10 min, the transient process saturation at =30 min, and the tissue mass improvement by =1-3%. No statistically-relevant differences between the measured properties of the intact and treated DBPs were observed. Then, contact angles of wettability were measured for the considered DBPs using a recumbent drop method, while the observed results showed that treatments of DBP somewhat affects their surface energies, polarity, and hydrophilicity. Thus, our studies revealed that glutaraldehyde and plasma treatment overall impact the DBP-water interactions, but the resultant effects appear to be quite complex and comparable to the natural variability of the tissue properties. Such a variability was attributed to the natural heterogeneity of tissues, which was confirmed by the THz microscopy data. Our findings are important for further optimization of the scaffolds' preparation and treatment technologies. They pave the way for THz technology use as a non-invasive diagnosis tool in tissue engineering and regenerative medicine.

Revkova V.A., Sidoruk K.V., Kalsin V.A., Melnikov P.A., Konoplyannikov M.A., Kotova S., Frolova A.A., Rodionov S.A., Smorchkov M.M., Kovalev A.V., Troitskiy A.V., Timashev P.S., Chekhonin V.P., Bogush V.G., Baklaushev V.P.

The interaction of neural progenitor cells (NPCs) with the extracellular matrix (ECM) plays an important role in neural tissue regeneration. Understanding which motifs of the ECM proteins are crucial for normal NPC adhesion, proliferation, and differentiation is important in order to create more adequate tissue engineered models of neural tissue and to efficiently study the central nervous system regeneration mechanisms. We have shown earlier that anisotropic matrices prepared from a mixture of recombinant dragline silk proteins, such as spidroin 1 and spidroin 2, by electrospinning are biocompatible with NPCs and provide good proliferation and oriented growth of neurites. This study objective was to find the effects of spidroin-based electrospun materials, modified with peptide motifs of the extracellular matrix proteins (RGD, IKVAV, and VAEIDGIEL) on adhesion, proliferation, and differentiation of directly reprogrammed neural precursor cells (drNPCs). The structural and biomechanical studies have shown that spidroin-based electrospun mats (SBEM), modified with ECM peptides, are characterized by a uniaxial orientation and elastic moduli in the swollen state, comparable to those of the dura mater. It has been found for the first time that drNPCs on SBEM mostly preserve their stemness in the growth medium and even in the differentiation medium with brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor, while addition of the mentioned ECM-peptide motifs may shift the balance toward neuroglial differentiation. We have demonstrated that the RGD motif promotes formation of a lower number of neurons with longer neurites, while the IKVAV motif is characterized by formation of a greater number of NF200-positive neurons with shorter neurites. At the same time, all the studied matrices preserve up to 30% of neuroglial progenitor cells, phenotypically similar to radial glia derived from the subventricular zone. We believe that, by using this approach and modifying spidroin by various ECM-motifs or other substances, one may create an in vitro model for the neuroglial stem cell niche with the potential control of their differentiation.

Zaytsev K.I., Kurlov V.N., Skorobogatiy M., Reshetov I.V., Tuchin V.V.

The editorial introduces a special section of the Journal of Biomedical Optics on Advances in Terahertz Biomedical Science and Applications. This special section includes one review and ten research papers addressing the complex challenges of terahertz biophotonics and related areas of biomedical optics.

Nikitkina A.I., Bikmulina P.Y., Gafarova E.R., Kosheleva N.V., Efremov Y.M., Bezrukov E.A., Butnaru D.V., Dolganova I.N., Chernomyrdin N.V., Cherkasova O.P., Gavdush A.A., Timashev P.S.

Abstract. Significance: Terahertz (THz) radiation has demonstrated a great potential in biomedical applications over the past three decades, mainly due to its non-invasive and label-free nature. Among all biological specimens, skin tissue is an optimal sample for the application of THz-based methods because it allows for overcoming some intrinsic limitations of the technique, such as a small penetration depth (0.1 to 0.3 mm for the skin, on average). Aim: We summarize the modern research results achieved when THz technology was applied to the skin, considering applications in both imaging/detection and treatment/modulation of the skin constituents. Approach: We perform a review of literature and analyze the recent research achievements in THz applications for skin diagnosis and investigation. Results: The reviewed results demonstrate the possibilities of THz spectroscopy and imaging, both pulsed and continuous, for diagnosis of skin melanoma and non-melanoma cancer, dysplasia, scars, and diabetic condition, mainly based on the analysis of THz optical properties. The possibility of modulating cell activity and treatment of various diseases by THz-wave exposure is shown as well. Conclusions: The rapid development of THz technologies and the obtained research results for skin tissue highlight the potential of THz waves as a research and therapeutic instrument. The perspectives on the use of THz radiation are related to both non-invasive diagnostics and stimulation and control of different processes in a living skin tissue for regeneration and cancer treatment.

Rytik A.P., Tuchin V.V.

Abstract The paper presents the results of modern research on the effects of electromagnetic terahertz radiation in the frequency range 0.5–100 THz at different levels of power density and exposure time on the viability of normal and cancer cells. As an accompanying tool for monitoring the effect of radiation on biological cells and tissues, spectroscopic research methods in the terahertz frequency range are described, and attention is focused on the possibility of using the spectra of interstitial water as a marker of pathological processes. The problem of the safety of terahertz radiation for the human body from the point of view of its effect on the structures and systems of biological cells is also considered. Graphical Abstract

Kinreich S., Bialer-Tsypin A., Viner-Breuer R., Keshet G., Suhler R., Lim P.S., Golan-Lev T., Yanuka O., Turjeman A., Ram O., Meshorer E., Egli D., Yilmaz A., Benvenisty N.

Sitnikov D.S., Revkova V.A., Ilina I.V., Shatalova R.O., Konoplyannikov M.A., Kalsin V.A., Baklaushev V.P.

Krawczyk E., Kitlińska J.

Preclinical in vitro and in vivo models remain indispensable tools in cancer research. These classic models, including two- and three-dimensional cell culture techniques and animal models, are crucial for basic and translational studies. However, each model has its own limitations and typically does not fully recapitulate the course of the human disease. Therefore, there is an urgent need for the development of novel, advanced systems that can allow for efficient evaluation of the mechanisms underlying cancer development and progression, more accurately reflect the disease pathophysiology and complexity, and effectively inform therapeutic decisions for patients. Preclinical models are especially important for rare cancers, such as neuroblastoma, where the availability of patient-derived specimens that could be used for potential therapy evaluation and screening is limited. Neuroblastoma modeling is further complicated by the disease heterogeneity. In this review, we present the current status of preclinical models for neuroblastoma research, discuss their development and characteristics emphasizing strengths and limitations, and describe the necessity of the development of novel, more advanced and clinically relevant approaches.