Effects of electromagnetic waves on pathogenic viruses and related mechanisms: a review in the Journal of Virology

Pathogenic viral infections have become a major public health problem worldwide. Viruses can infect all cellular organisms and cause varying degrees of injury and damage, leading to disease and even death. With the prevalence of highly pathogenic viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is an urgent need to develop effective and safe methods to inactivate pathogenic viruses. Traditional methods for inactivating pathogenic viruses are practical but have some limitations. With the characteristics of high penetrating power, physical resonance and no pollution, electromagnetic waves have become a potential strategy for the inactivation of pathogenic viruses and are attracting increasing attention. This article provides an overview of recent publications on the impact of electromagnetic waves on pathogenic viruses and their mechanisms, as well as the prospects for the use of electromagnetic waves for the inactivation of pathogenic viruses, as well as new ideas and methods for such inactivation.
Many viruses spread rapidly, persist for a long time, are highly pathogenic and can cause global epidemics and serious health risks. Prevention, detection, testing, eradication and treatment are key steps to stop the spread of the virus. Rapid and efficient elimination of pathogenic viruses includes prophylactic, protective, and source elimination. Inactivation of pathogenic viruses by physiological destruction to reduce their infectivity, pathogenicity and reproductive capacity is an effective method of their elimination. Traditional methods, including high temperature, chemicals and ionizing radiation, can effectively inactivate pathogenic viruses. However, these methods still have some limitations. Therefore, there is still an urgent need to develop innovative strategies for the inactivation of pathogenic viruses.
The emission of electromagnetic waves has the advantages of high penetrating power, rapid and uniform heating, resonance with microorganisms and plasma release, and is expected to become a practical method for inactivating pathogenic viruses [1,2,3]. The ability of electromagnetic waves to inactivate pathogenic viruses was demonstrated in the last century [4]. In recent years, the use of electromagnetic waves for the inactivation of pathogenic viruses has attracted increasing attention. This article discusses the effect of electromagnetic waves on pathogenic viruses and their mechanisms, which can serve as a useful guide for basic and applied research.
The morphological characteristics of viruses can reflect functions such as survival and infectivity. It has been demonstrated that electromagnetic waves, especially ultra high frequency (UHF) and ultra high frequency (EHF) electromagnetic waves, can disrupt the morphology of viruses.
Bacteriophage MS2 (MS2) is often used in various research areas such as disinfection evaluation, kinetic modeling (aqueous), and biological characterization of viral molecules [5, 6]. Wu found that microwaves at 2450 MHz and 700 W caused aggregation and significant shrinkage of MS2 aquatic phages after 1 minute of direct irradiation [1]. After further investigation, a break in the surface of the MS2 phage was also observed [7]. Kaczmarczyk [8] exposed suspensions of samples of coronavirus 229E (CoV-229E) to millimeter waves with a frequency of 95 GHz and a power density of 70 to 100 W/cm2 for 0.1 s. Large holes can be found in the rough spherical shell of the virus, which leads to the loss of its contents. Exposure to electromagnetic waves can be destructive to viral forms. However, changes in morphological properties, such as shape, diameter and surface smoothness, after exposure to the virus with electromagnetic radiation are unknown. Therefore, it is important to analyze the relationship between morphological features and functional disorders, which can provide valuable and convenient indicators for assessing virus inactivation [1].
The viral structure usually consists of an internal nucleic acid (RNA or DNA) and an external capsid. Nucleic acids determine the genetic and replication properties of viruses. The capsid is the outer layer of regularly arranged protein subunits, the basic scaffolding and antigenic component of viral particles, and also protects nucleic acids. Most viruses have an envelope structure made up of lipids and glycoproteins. In addition, envelope proteins determine the specificity of the receptors and serve as the main antigens that the host’s immune system can recognize. The complete structure ensures the integrity and genetic stability of the virus.
Research has shown that electromagnetic waves, especially UHF electromagnetic waves, can damage the RNA of disease-causing viruses. Wu [1] directly exposed the aqueous environment of the MS2 virus to 2450 MHz microwaves for 2 minutes and analyzed the genes encoding protein A, capsid protein, replicase protein, and cleavage protein by gel electrophoresis and reverse transcription polymerase chain reaction. RT-PCR). These genes were progressively destroyed with increasing power density and even disappeared at the highest power density. For example, the expression of the protein A gene (934 bp) significantly decreased after exposure to electromagnetic waves with a power of 119 and 385 W and completely disappeared when the power density was increased to 700 W. These data indicate that electromagnetic waves can, depending on the dose, destroy the structure of the nucleic acids of viruses.
Recent studies have shown that the effect of electromagnetic waves on pathogenic viral proteins is mainly based on their indirect thermal effect on mediators and their indirect effect on protein synthesis due to the destruction of nucleic acids [1, 3, 8, 9]. However, athermic effects can also change the polarity or structure of viral proteins [1, 10, 11]. The direct effect of electromagnetic waves on fundamental structural/non-structural proteins such as capsid proteins, envelope proteins or spike proteins of pathogenic viruses still requires further study. It has recently been suggested that 2 minutes of electromagnetic radiation at a frequency of 2.45 GHz with a power of 700 W can interact with different fractions of protein charges through the formation of hot spots and oscillating electric fields through purely electromagnetic effects [12].
The envelope of a pathogenic virus is closely related to its ability to infect or cause disease. Several studies have reported that UHF and microwave electromagnetic waves can destroy the shells of disease-causing viruses. As mentioned above, distinct holes can be detected in the viral envelope of coronavirus 229E after 0.1 second exposure to the 95 GHz millimeter wave at a power density of 70 to 100 W/cm2 [8]. The effect of resonant energy transfer of electromagnetic waves can cause enough stress to destroy the structure of the virus envelope. For enveloped viruses, after rupture of the envelope, infectivity or some activity usually decreases or is completely lost [13, 14]. Yang [13] exposed the H3N2 (H3N2) influenza virus and the H1N1 (H1N1) influenza virus to microwaves at 8.35 GHz, 320 W/m² and 7 GHz, 308 W/m², respectively, for 15 minutes. To compare the RNA signals of pathogenic viruses exposed to electromagnetic waves and a fragmented model frozen and immediately thawed in liquid nitrogen for several cycles, RT-PCR was performed. The results showed that the RNA signals of the two models are very consistent. These results indicate that the physical structure of the virus is disrupted and the envelope structure is destroyed after exposure to microwave radiation.
The activity of a virus can be characterized by its ability to infect, replicate and transcribe. Viral infectivity or activity is usually assessed by measuring viral titers using plaque assays, tissue culture median infective dose (TCID50), or luciferase reporter gene activity. But it can also be assessed directly by isolating live virus or by analyzing viral antigen, viral particle density, virus survival, etc.
It has been reported that UHF, SHF and EHF electromagnetic waves can directly inactivate viral aerosols or waterborne viruses. Wu [1] exposed MS2 bacteriophage aerosol generated by a laboratory nebulizer to electromagnetic waves with a frequency of 2450 MHz and a power of 700 W for 1.7 min, while the MS2 bacteriophage survival rate was only 8.66%. Similar to MS2 viral aerosol, 91.3% of aqueous MS2 was inactivated within 1.5 minutes after exposure to the same dose of electromagnetic waves. In addition, the ability of electromagnetic radiation to inactivate the MS2 virus was positively correlated with power density and exposure time. However, when the deactivation efficiency reaches its maximum value, the deactivation efficiency cannot be improved by increasing the exposure time or increasing the power density. For example, the MS2 virus had a minimal survival rate of 2.65% to 4.37% after exposure to 2450 MHz and 700 W electromagnetic waves, and no significant changes were found with increasing exposure time. Siddharta [3] irradiated a cell culture suspension containing hepatitis C virus (HCV)/human immunodeficiency virus type 1 (HIV-1) with electromagnetic waves at a frequency of 2450 MHz and a power of 360 W. They found that virus titers dropped significantly after 3 minutes of exposure, indicating that electromagnetic wave radiation is effective against HCV and HIV-1 infectivity and helps prevent transmission of the virus even when exposed together. When irradiating HCV cell cultures and HIV-1 suspensions with low-power electromagnetic waves with a frequency of 2450 MHz, 90 W or 180 W, no change in the virus titer, determined by the luciferase reporter activity, and a significant change in viral infectivity were observed. at 600 and 800 W for 1 minute, the infectivity of both viruses did not significantly decrease, which is believed to be related to the power of the electromagnetic wave radiation and the time of critical temperature exposure.
Kaczmarczyk [8] first demonstrated the lethality of EHF electromagnetic waves against waterborne pathogenic viruses in 2021. They exposed samples of coronavirus 229E or poliovirus (PV) to electromagnetic waves at a frequency of 95 GHz and a power density of 70 to 100 W/cm2 for 2 seconds. The inactivation efficiency of the two pathogenic viruses was 99.98% and 99.375%, respectively. which indicates that EHF electromagnetic waves have broad application prospects in the field of virus inactivation.
The effectiveness of UHF inactivation of viruses has also been evaluated in various media such as breast milk and some materials commonly used in the home. The researchers exposed anesthesia masks contaminated with adenovirus (ADV), poliovirus type 1 (PV-1), herpesvirus 1 (HV-1) and rhinovirus (RHV) to electromagnetic radiation at a frequency of 2450 MHz and a power of 720 watts. They reported that tests for ADV and PV-1 antigens became negative, and HV-1, PIV-3, and RHV titers dropped to zero, indicating complete inactivation of all viruses after 4 minutes of exposure [15, 16]. Elhafi [17] directly exposed swabs infected with avian infectious bronchitis virus (IBV), avian pneumovirus (APV), Newcastle disease virus (NDV), and avian influenza virus (AIV) to a 2450 MHz, 900 W microwave oven. lose their infectivity. Among them, APV and IBV were additionally detected in cultures of tracheal organs obtained from chick embryos of the 5th generation. Although the virus could not be isolated, the viral nucleic acid was still detected by RT-PCR. Ben-Shoshan [18] directly exposed 2450 MHz, 750 W electromagnetic waves to 15 cytomegalovirus (CMV) positive breast milk samples for 30 seconds. Antigen detection by Shell-Vial showed complete inactivation of CMV. However, at 500 W, 2 out of 15 samples did not achieve complete inactivation, which indicates a positive correlation between the inactivation efficiency and the power of electromagnetic waves.
It is also worth noting that Yang [13] predicted the resonant frequency between electromagnetic waves and viruses based on established physical models. A suspension of H3N2 virus particles with a density of 7.5 × 1014 m-3, produced by virus-sensitive Madin Darby dog ​​kidney cells (MDCK), was directly exposed to electromagnetic waves at a frequency of 8 GHz and a power of 820 W/m² for 15 minutes. The level of inactivation of the H3N2 virus reaches 100%. However, at a theoretical threshold of 82 W/m2, only 38% of the H3N2 virus was inactivated, suggesting that the efficiency of EM-mediated virus inactivation is closely related to power density. Based on this study, Barbora [14] calculated the resonant frequency range (8.5–20 GHz) between electromagnetic waves and SARS-CoV-2 and concluded that 7.5 × 1014 m-3 of SARS-CoV- 2 exposed to electromagnetic waves A wave with a frequency of 10-17 GHz and a power density of 14.5 ± 1 W/m2 for approximately 15 minutes will result in 100% deactivation. A recent study by Wang [19] showed that the resonant frequencies of SARS-CoV-2 are 4 and 7.5 GHz, confirming the existence of resonant frequencies independent of virus titer.
In conclusion, we can say that electromagnetic waves can affect aerosols and suspensions, as well as the activity of viruses on surfaces. It was found that the effectiveness of inactivation is closely related to the frequency and power of electromagnetic waves and the medium used for the growth of the virus. In addition, electromagnetic frequencies based on physical resonances are very important for virus inactivation [2, 13]. Until now, the effect of electromagnetic waves on the activity of pathogenic viruses has mainly focused on changing infectivity. Due to the complex mechanism, several studies have reported the effect of electromagnetic waves on the replication and transcription of pathogenic viruses.
The mechanisms by which electromagnetic waves inactivate viruses are closely related to the type of virus, frequency and power of electromagnetic waves, and the growth environment of the virus, but remain largely unexplored. Recent research has focused on the mechanisms of thermal, athermal, and structural resonant energy transfer.
The thermal effect is understood as an increase in temperature caused by high-speed rotation, collision and friction of polar molecules in tissues under the influence of electromagnetic waves. Due to this property, electromagnetic waves can raise the temperature of the virus above the threshold of physiological tolerance, causing the death of the virus. However, viruses contain few polar molecules, which suggests that direct thermal effects on viruses are rare [1]. On the contrary, there are many more polar molecules in the medium and environment, such as water molecules, which move in accordance with the alternating electric field excited by electromagnetic waves, generating heat through friction. The heat is then transferred to the virus to raise its temperature. When the tolerance threshold is exceeded, nucleic acids and proteins are destroyed, which ultimately reduces infectivity and even inactivates the virus.
Several groups have reported that electromagnetic waves can reduce the infectivity of viruses through thermal exposure [1, 3, 8]. Kaczmarczyk [8] exposed suspensions of coronavirus 229E to electromagnetic waves at a frequency of 95 GHz with a power density of 70 to 100 W/cm² for 0.2-0.7 s. The results showed that a temperature increase of 100°C during this process contributed to the destruction of the virus morphology and reduced virus activity. These thermal effects can be explained by the action of electromagnetic waves on the surrounding water molecules. Siddharta [3] irradiated HCV-containing cell culture suspensions of different genotypes, including GT1a, GT2a, GT3a, GT4a, GT5a, GT6a and GT7a, with electromagnetic waves at a frequency of 2450 MHz and a power of 90 W and 180 W, 360 W, 600 W and 800 Tue With an increase in the temperature of the cell culture medium from 26°C to 92°C, electromagnetic radiation reduced the infectivity of the virus or completely inactivated the virus. But HCV was exposed to electromagnetic waves for a short time at low power (90 or 180 W, 3 minutes) or higher power (600 or 800 W, 1 minute), while there was no significant increase in temperature and a significant change in the virus was not observed infectivity or activity.
The above results indicate that the thermal effect of electromagnetic waves is a key factor influencing the infectivity or activity of pathogenic viruses. In addition, numerous studies have shown that the thermal effect of electromagnetic radiation inactivates pathogenic viruses more effectively than UV-C and conventional heating [8, 20, 21, 22, 23, 24].
In addition to thermal effects, electromagnetic waves can also change the polarity of molecules such as microbial proteins and nucleic acids, causing the molecules to rotate and vibrate, resulting in reduced viability or even death [10]. It is believed that the rapid switching of the polarity of electromagnetic waves causes protein polarization, which leads to twisting and curvature of the protein structure and, ultimately, to protein denaturation [11].
The nonthermal effect of electromagnetic waves on virus inactivation remains controversial, but most studies have shown positive results [1, 25]. As we mentioned above, electromagnetic waves can directly penetrate the envelope protein of the MS2 virus and destroy the nucleic acid of the virus. In addition, MS2 virus aerosols are much more sensitive to electromagnetic waves than aqueous MS2. Due to less polar molecules, such as water molecules, in the environment surrounding MS2 virus aerosols, athermic effects may play a key role in electromagnetic wave-mediated virus inactivation [1].
The phenomenon of resonance refers to the tendency of a physical system to absorb more energy from its environment at its natural frequency and wavelength. Resonance occurs in many places in nature. It is known that viruses resonate with microwaves of the same frequency in a limited acoustic dipole mode, a resonance phenomenon [2, 13, 26]. Resonant modes of interaction between an electromagnetic wave and a virus are attracting more and more attention. The effect of efficient structural resonance energy transfer (SRET) from electromagnetic waves to closed acoustic oscillations (CAV) in viruses can lead to rupture of the viral membrane due to opposing core-capsid vibrations. In addition, the overall effectiveness of SRET is related to the nature of the environment, where the size and pH of the viral particle determine the resonant frequency and energy absorption, respectively [2, 13, 19].
The physical resonance effect of electromagnetic waves plays a key role in the inactivation of enveloped viruses, which are surrounded by a bilayer membrane embedded in viral proteins. The researchers found that the deactivation of H3N2 by electromagnetic waves with a frequency of 6 GHz and a power density of 486 W/m² was mainly caused by the physical rupture of the shell due to the resonance effect [13]. The temperature of the H3N2 suspension increased by only 7°C after 15 minutes of exposure, however, for inactivation of the human H3N2 virus by thermal heating, a temperature above 55°C is required [9]. Similar phenomena have been observed for viruses such as SARS-CoV-2 and H3N1 [13, 14]. In addition, the inactivation of viruses by electromagnetic waves does not lead to the degradation of viral RNA genomes [1,13,14]. Thus, the inactivation of the H3N2 virus was promoted by physical resonance rather than thermal exposure [13].
Compared to the thermal effect of electromagnetic waves, the inactivation of viruses by physical resonance requires lower dose parameters, which are below the microwave safety standards established by the Institute of Electrical and Electronics Engineers (IEEE) [2, 13]. The resonant frequency and power dose depend on the physical properties of the virus, such as particle size and elasticity, and all viruses within the resonant frequency can be effectively targeted for inactivation. Due to the high penetration rate, the absence of ionizing radiation, and good safety, virus inactivation mediated by the athermic effect of CPET is promising for the treatment of human malignant diseases caused by pathogenic viruses [14, 26].
Based on the implementation of the inactivation of viruses in the liquid phase and on the surface of various media, electromagnetic waves can effectively deal with viral aerosols [1, 26], which is a breakthrough and is of great importance for controlling the transmission of the virus and preventing the transmission of the virus in society. epidemic. Moreover, the discovery of the physical resonance properties of electromagnetic waves is of great importance in this field. As long as the resonant frequency of a particular virion and electromagnetic waves are known, all viruses within the resonant frequency range of the wound can be targeted, which cannot be achieved with traditional virus inactivation methods [13,14,26]. Electromagnetic inactivation of viruses is a promising research with great research and applied value and potential.
Compared with traditional virus killing technology, electromagnetic waves have the characteristics of simple, effective, practical environmental protection when killing viruses due to its unique physical properties [2, 13]. However, many problems remain. First, modern knowledge is limited to the physical properties of electromagnetic waves, and the mechanism of energy utilization during the emission of electromagnetic waves has not been disclosed [10, 27]. Microwaves, including millimeter waves, have been widely used to study virus inactivation and its mechanisms, however, studies of electromagnetic waves at other frequencies, especially at frequencies from 100 kHz to 300 MHz and from 300 GHz to 10 THz, have not been reported. Secondly, the mechanism of killing pathogenic viruses by electromagnetic waves has not been elucidated, and only spherical and rod-shaped viruses have been studied [2]. In addition, virus particles are small, cell-free, mutate easily, and spread rapidly, which can prevent virus inactivation. Electromagnetic wave technology still needs to be improved to overcome the hurdle of inactivating pathogenic viruses. Finally, high absorption of radiant energy by polar molecules in the medium, such as water molecules, results in energy loss. In addition, the effectiveness of SRET may be affected by several unidentified mechanisms in viruses [28]. The SRET effect can also modify the virus to adapt to its environment, resulting in resistance to electromagnetic waves [29].
In the future, the technology of virus inactivation using electromagnetic waves needs to be further improved. Fundamental scientific research should be aimed at elucidating the mechanism of virus inactivation by electromagnetic waves. For example, the mechanism of using the energy of viruses when exposed to electromagnetic waves, the detailed mechanism of non-thermal action that kills pathogenic viruses, and the mechanism of the SRET effect between electromagnetic waves and various types of viruses should be systematically elucidated. Applied research should focus on how to prevent excessive absorption of radiation energy by polar molecules, study the effect of electromagnetic waves of different frequencies on various pathogenic viruses, and study the non-thermal effects of electromagnetic waves in the destruction of pathogenic viruses.
Electromagnetic waves have become a promising method for the inactivation of pathogenic viruses. Electromagnetic wave technology has the advantages of low pollution, low cost, and high pathogen virus inactivation efficiency, which can overcome the limitations of traditional anti-virus technology. However, further research is needed to determine the parameters of electromagnetic wave technology and elucidate the mechanism of virus inactivation.
A certain dose of electromagnetic wave radiation can destroy the structure and activity of many pathogenic viruses. The efficiency of virus inactivation is closely related to frequency, power density, and exposure time. In addition, potential mechanisms include thermal, athermal, and structural resonance effects of energy transfer. Compared with traditional antiviral technologies, electromagnetic wave based virus inactivation has the advantages of simplicity, high efficiency and low pollution. Therefore, electromagnetic wave-mediated virus inactivation has become a promising antiviral technique for future applications.
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