Effect of terahertz radiation on cells and cellular structures (Review)

Abstract

Effect of terahertz radiation on cells and cellular structures (Review) Rytik AP, Tuchin VV. Effect of terahertz radiation on cells and cellular structures. Front Optoelectron. 2025 Jan 27;18(1):2. doi: 10.1007/s12200-024-00146-y. 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. Conclusion The presented data show that THz radiation has a variety of effects on cells, which are manifested in the disruption of the properties of cell membranes, the formation of pores, the activation of ion channels, and changes in their proliferation and viability [110]. Possible mechanisms that determine the reaction of cells to THz radiation may be the following: • a change in the conformation of membrane proteins, which triggers an intracellular cascade of regulators of the genetic and enzymatic systems and the permeability of cell membranes for various substances; • a change in the conformation of membrane proteins that perceive external regulatory signals; • change in the conformation of membrane proteins that are pumps or channels for the transport of various substances into and out of the cell; • redistribution of the electric charge on the cell membrane; • excitation of resonant oscillations of macromolecules that make up the cell membrane and the cytoskeleton as a whole. Thus, fundamentally, THz radiation does not cause the breaking or restoration of chemical covalent bonds, since the quantum energy is insufficient for this, 1 THz − 4.1 meV. However, this radiation, in its frequencies, falls into the region of vibrational–rotational movements of biological molecules and water and can excite energy levels of vibrational–rotational transitions of proteins and water, and thereby change the spatial conformation of proteins, which can affect various interactions between proteins, protein and water molecules. It is generally accepted that there are several mechanisms that determine the effect of the response of living cells to THz radiation, in particular [1]: • redistribution of electrical charge on the cell membrane, changing the ratio of concentrations of bound and free water; • excitation of resonant vibrations of macromolecules that make up the cell membrane and the cytoskeleton as a whole; • change in the conformation of membrane proteins. Water molecules themselves can be considered as a universal marker in the THz frequency range, which is sensitive to various vital processes occurring in living tissues and cells. Compared to what is traditionally described in dielectric spectroscopy, in the THz frequency range water as a marker allows one to obtain new information about biological systems. Moving from the gigahertz (GHz) to the THz range, we are gradually approaching various vibrational–rotational processes that are determined by the interaction of water molecules with surrounding molecular systems [23]. Biomacromolecules, being excited, absorb part or all of the energy of electromagnetic waves, depending on the frequency of the incident radiation [26]. Since the generalized terahertz range (0.1–100 THz) partially overlaps with the vibration spectrum of biomolecules, terahertz waves can greatly enhance vibrations of biomolecule bonds such as twisting, stretching, and bending through resonant excitation [111]. However, early studies of the biological effects induced by optical stimulation focused on the infrared region, which promotes the strong absorption of incoming energy by water and its conversion into heat [112, 113]. While heat alters transmembrane capacitance or ion channel activity and hence induces biological responses, it inevitably also causes a transient increase in local temperature. On the other hand, terahertz wave modulation is seen as a promising approach for interfering with biophysical processes without being damaged by electromagnetic radiation. The study of non-thermal biological effects of infrared radiation has attracted close attention from both opticians and biologists. In addition, THz waves with low photon energy are unlikely to cause ionizing effects, thus will not damage genome integrity as other radiation intervention approaches might [112]. It can be concluded that currently there is no full consensus in the scientific community as to whether THz radiation has a damaging effect on biological objects at various levels of organization [83, 114]. Therefore, an increase in studies using THz radiation to monitor the activity of uncontrolled dividing cells is expected in the near future. The development of new high-resolution THz diagnostic methods in combination with AI technologies will take cancer diagnosis and therapy to a new level. It is obvious that more and more new data will appear soon for THz diagnostics and therapy of tumor oncological processes. In addition, theranostics technologies, where THz radiation from the same source is used first for diagnosis and then at increased energy parameters for therapy within a single protocol, have not yet received proper development, but are undoubtedly promising. Open access paper: link.springer.com

AI evidence extraction

Main findings

This review summarizes research on terahertz (0.5–100 THz) electromagnetic radiation at different power densities and exposure times, reporting a variety of cellular effects including disruption of membrane properties, pore formation, ion channel activation, and changes in proliferation and viability. It notes that there is currently no full consensus on whether THz radiation has damaging effects on biological objects at different levels of organization.

Outcomes measured

• Cell viability (normal and cancer cells)
• Cell membrane properties (disruption)
• Pore formation in membranes
• Ion channel activation
• Cell proliferation
• Spectroscopic THz monitoring/biomarkers (interstitial water spectra)
• Safety of THz radiation for the human body (cellular structures/systems)

Limitations

• Narrative review summarizing prior studies; no specific study designs, sample sizes, or quantitative effect estimates reported in the abstract
• Exposure metrics (exact power densities, durations, SAR) are not specified in the abstract
• Authors state there is no full consensus in the scientific community regarding damaging effects

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    "study_type": "review",
    "exposure": {
        "band": "THz",
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "varied (different power density and exposure time; not specified)"
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "Cell viability (normal and cancer cells)",
        "Cell membrane properties (disruption)",
        "Pore formation in membranes",
        "Ion channel activation",
        "Cell proliferation",
        "Spectroscopic THz monitoring/biomarkers (interstitial water spectra)",
        "Safety of THz radiation for the human body (cellular structures/systems)"
    ],
    "main_findings": "This review summarizes research on terahertz (0.5–100 THz) electromagnetic radiation at different power densities and exposure times, reporting a variety of cellular effects including disruption of membrane properties, pore formation, ion channel activation, and changes in proliferation and viability. It notes that there is currently no full consensus on whether THz radiation has damaging effects on biological objects at different levels of organization.",
    "effect_direction": "mixed",
    "limitations": [
        "Narrative review summarizing prior studies; no specific study designs, sample sizes, or quantitative effect estimates reported in the abstract",
        "Exposure metrics (exact power densities, durations, SAR) are not specified in the abstract",
        "Authors state there is no full consensus in the scientific community regarding damaging effects"
    ],
    "evidence_strength": "insufficient",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "terahertz radiation",
        "THz",
        "0.5–100 THz",
        "cells",
        "cell membranes",
        "pores",
        "ion channels",
        "proliferation",
        "viability",
        "spectroscopy",
        "water marker",
        "non-thermal effects",
        "safety"
    ],
    "suggested_hubs": []
}

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