Terahertz radiation can disrupt proteins in living cells

https://phys.org/news/2020-06-terahertz-disrupt-proteins-cells.html

Researchers from the RIKEN Center for Advanced Photonics and collaborators have discovered that terahertz radiation, contradicting conventional belief, can disrupt proteins in living cells without killing them.

This finding implies that terahertz radiation, which was long considered impractical to use, may have applications in manipulating cell functions for the treatment of cancer, for example, but also that there may be safety issues to consider. Terahertz radiation is a portion of the electromagnetic spectrum between microwaves and infrared light, which is often known as the "terahertz gap" because of the current lack of technology to manipulate it efficiently. Because terahertz radiation is stopped by liquids and is non-ionizing—meaning that it does not damage DNA in the way that X-rays do—work is ongoing to put it to use in areas such as airport baggage inspections. It has generally been considered to be safe for use in tissues. However, some recent studies have found that it may have some direct effect on DNA, though it has little ability to actually penetrate into tissues, meaning that this effect would only be on surface skin cells.

One issue that has remained unexplored, however, is whether terahertz radiation can affect biological tissues even after it has been stopped, through the propagation of energy waves into the tissue. The research group from RAP recently discovered that the energy from the light could enter into water as a shockwave. Considering this, the group decided to investigate whether terahertz light could also have an effect like this on tissue.

They chose to investigate using a protein called actin, which is a key element that provides structure to living cells. It can exist in two conformations known as (G)-actin and (F)-actin, which have different structures and functions. The (F)-actin is a long filament made up of polymer chains of proteins. Using fluorescence microscopy, they looked at the effect of terahertz radiation on the growth of chains in an aqueous solution of actin, and found that it led to a decrease in filaments. In other words, the terahertz light was somehow preventing the (G)-actin from forming chains and becoming (F)-actin. They considered the possibility that it was caused by a rise in temperature, but found that the small rise, of around 1.4 degrees Celsius, was not sufficient to explain the change. The researchers concluded that it was most likely caused by a shockwave. To further test the hypothesis, they performed experiments in living cells, and found that in the cells, as in the solution, the formation of actin filaments was disrupted. However, there was no sign that the radiation caused cells to die.

Shota Yamazaki, the first author of the study published in Scientific Reports, says, "It was quite interesting for us to see that terahertz radiation can have an effect on proteins inside cells without killing them cells themselves. We will be interested in looking for potential applications in cancer and other diseases."

Chiko Otani, the leader of the research groups, says, "Terahertz radiation is coming into a variety of applications today, and it is important to come to a full understanding of its effect on biological tissues, both to gauge any risks and to look for potential applications."

Abstract-Evaluation of cancer tissue morphology via THz spectroscopic imaging: Human lung and small intestine malignancies

Woon-Gi Yeo, Ogan Gurel, Charles L. Hitchcock, Sungchan Park, Kubilay Sertel,  Niru K.Nahar,

https://www.sciencedirect.com/science/article/pii/S1350449518307862

We investigate the potential of terahertz spectroscopic imaging for assessment of malignant tissues in human lung and small intestine using a reflection-mode time-domain spectroscopy system spanning the 60 GHz–2 THz band. These two tissue groups are among the few that can be reached via an endoscopic sensor, thus potentially allowing for in-situ assessment of suspected tumors. As an initial study toward this goal, we characterized formalin-fixed and paraffin-embedded tissue blocks using a commercially-available reflection-mode time domain spectroscopy system. We verify that the measured THz responses of these tissue groups reveal key differences in their morphology, material density, and electrical properties. The spectroscopic characteristics in the THz band are contrasted with the histopathologic assessment of hematoxylin and eosin stained tissue slices to demonstrate the potential of THz spectroscopy for evaluating lung and small intestine malignancies. For both types of organ tissues, it is demonstrated that the THz images provide key discriminatory information such as tissue morphology, cancer margin, and necrotic areas in the tumor.

NIH/NCI Grant Will Further Investigation Of Breast Tumor Margin Assessment

http://www.publicnow.com/view/6E88074280A7DB1F6CC13A0E596892AC2EB0B903

Professor Magda El-Shenawee and graduate assistant, Tyler Bowman, use THz imaging technology to assess the margins of cancerous breast tumors.

The National Cancer Institute, part of the National Institutes of Health, has awarded a three-year, $424,081 grant to Magda El-Shenawee, electrical engineering professor, for her work on an intraoperative and rapid method of detecting positive cancer margins during conservative breast cancer surgery, or lumpectomy.

Standard medical imaging techniques insufficiently provide clear assessment of breast tissue margins, resulting in a reported second surgery rate of 20 to 40 percent.

The grant will allow El-Shenawee's research team to advance the assessment of breast tumor margins using new Terahertz imaging technology, which will provide the groundwork for fast, intraoperative tumor margin assessment and significantly reduce the occurrence of second surgeries, cancer reoccurrence and metastasis.

'When we talk to any doctor about the tumor margins, they see issues,' said El-Shenawee. 'If they can't get all of the tumor in the first operation, two things can occur. Cancer can come back in the same spot, or the cancer can metastasize and spread to other organs. That is the danger of breast cancer.'

Terahertz technology offers high, sub-millimeter resolution, as well as sensitivity to water content, which can be a major contrast factor in biological tissues. The researchers will focus their efforts on imaging two types of tumor tissues - one developed from phantom tissues that mimic freshly excised human tumors and the other freshly excised tumors grown in mice.

'We believe this new Terahertz technology will give us better images of the tissue than current, standard methods,' El-Shenawee said.

El-Shenawee will collaborate with University of Arkansas professors Narasimhan Rajaram, assistant professor of biomedical engineering; Jingxian Wu, associate professor of electrical engineering, Avishek Chakraborty, assistant professor of mathematical sciences; and Tyler Bowman, doctoral student in electrical engineering. Bowman is an NSF Graduate Fellow and University of Arkansas Distinguished Doctoral Fellow. El-Shenawee will also collaborate with Keith Bailey, director of the Oklahoma Animal Disease Diagnostic Laboratory at Oklahoma State University; and with Lucas Campbell, M.D., pathologist at Northwest Arkansas Pathology Associates in Fayetteville.

Editor-selected comments will be published below. No abusive material, personal attacks, profanity, spam or material of a similar nature will be considered for publication.

Abstract-Terahertz thermometry of gold nanospheres in water

Fabio Novelli, James W. M. Chon, and Jeffrey A. Davis

The photo-thermal effects of plasmonic nanoparticles are promising for cancer therapies. These treatments would greatly benefit from real-time, multi-scale temperature mapping by non-invasive means. Here we show that intense terahertz time domain spectroscopy can be used as a non-contact and high-resolution thermometer of water solutions. Using this technique, we measure the temperature change, triggered by femtosecond amplified laser pulses, of a solution of gold nanospheres in water. Extensions of this ultra-fast and non-invasive technique could open the door to real-time micro-thermometry of single cells without fluorescent labels.

© 2016 Optical Society of America

Full Article  |  PDF Article

Fun With Non-Ionizing Radiation

Neuroskeptic

http://blogs.discovermagazine.com/neuroskeptic/2016/12/06/non-ionizing-radiation/#.WEiIYeYrK71

Does non-ionizing radiation pose a health risk? Everyone knows that ionizing radiation, like gamma rays, can cause cancer by damaging DNA. But the scientific consensus is that there is no such risk from non-ionizing radiation such as radiowaves or Wi-Fi.

Yet according to a remarkable new paper from Magda Havas, the risk is real: it’s called When theory and observation collide: Can non-ionizing radiation cause cancer?

There are a few remarkable things about this paper but chief among them is its ‘graphical abstract’. Behold:

Here at Neuroskeptic I have written about research on the psychology of emoji’s, but this is the first time I’ve seen an emoji-based scientific illustration. Wow.

The paper itself goes on to explain that non-ionizing radiation is able to cause cancer and other problems by interfering with antioxidant (the yellow “kisser” depicted above) production in cells:

The body produces free radicals during metabolic activity and it also produces anti-oxidants as part of its natural repair mechanism. If the anti-oxidant repair mechanism is impaired free radical damage can result… The damage is generated not by direct ionization of atoms and molecules but rather by interference with anti-oxidant repair mechanisms.

The trouble is, Havas doesn’t say anything about how the disruption of anti-oxidants happens, and it’s not clear how it could. Non-ionizing radiation such as radiowaves and microwaves consists of photons, just like visible light, but at a lower frequency. Because the energy of a photon is proportional to its frequency, very high frequency photons (like gamma rays) have enough energy to disrupt atoms producing those dangerous, zombie-like, green free radicals.

But visible light can’t do this, and still less can microwaves or radiowaves. There’s no known mechanism by which such low-energy photons could harm living tissue – except that they can heat tissue up in high doses, but the amount of heating produced by radio and wireless devices is tiny.

Havas concludes that

The rapid deployment of wireless technology needs to be reconsidered. The potentially harmful effects of Wi-Fi in schools; smart meters on homes; the 5G network, as well as previous generations of cellular telecommunication have not been adequately tested for biological compatibility.

I don’t think we need to get into the debate over whether there is a statistical link between non-ionizing radiation sources and cancer. Some studies report an association, but if there is no physical mechanism that could explain it, my conclusion remains as follows: ¯\_(ツ)_/¯

(h/t Smut Clyde).

Havas, M. (2016). When theory and observation collide: Can non-ionizing radiation cause cancer? Environmental Pollution DOI: 10.1016/j.envpol.2016.10.018

Abstract-When theory and observation collide: Can non-ionizing radiation cause cancer?

• Magda Havas, B.Sc., Ph.D. 

• Trent School of the Environment, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 0G2, Canada

http://www.sciencedirect.com/science/article/pii/S0269749116309526

This paper attempts to resolve the debate about whether non-ionizing radiation (NIR) can cause cancer–a debate that has been ongoing for decades. The rationale, put forward mostly by physicists and accepted by many health agencies, is that, “since NIR does not have enough energy to dislodge electrons, it is unable to cause cancer.” This argument is based on a flawed assumption and uses the model of ionizing radiation (IR) to explain NIR, which is inappropriate. Evidence of free-radical damage has been repeatedly documented among humans, animals, plants and microorganisms for both extremely low frequency (ELF) electromagnetic fields (EMF) and for radio frequency (RF) radiation, neither of which is ionizing. While IR directly damages DNA, NIR interferes with the oxidative repair mechanisms resulting in oxidative stress, damage to cellular components including DNA, and damage to cellular processes leading to cancer. Furthermore, free-radical damage explains the increased cancer risks associated with mobile phone use, occupational exposure to NIR (ELF EMF and RFR), and residential exposure to power lines and RF transmitters including mobile phones, cell phone base stations, broadcast antennas, and radar installations.