Terahertz radiation is currently a focus of intense study and research for its potential uses in medical diagnostics, security and general scientific research. As such, there are many questions that scientists must answer about the potential human health risks associated with the practical use of this radiation.
New research done on lab-grown skin samples suggests that short and powerful bursts of THz radiation may cause DNA damage but increase the production of proteins that actually help the body fight cancer. The work is done in collaboration between physicists at the University of Alberta and molecular biologists at the University of Lethbridge in Canada. “While these investigations on the biological effects of intense THz pulses are only just beginning,” said Lyubov Titova of the University of Alberta, a member of the research team, “the fact that intense THz pulses can induce DNA damage but also DNA repair mechanisms in human skin tissue suggests that intense THz pulses need to be evaluated for possible therapeutic applications.”
But how does all of this work? We realize that THz radiation is sandwiched between the microwave wavelengths and the infrared wavelengths. This being the case, it acts like the microwave “relative” wavelength in the spectrum in that it is not energetic enough to break the chemical bonds that bind DNA together in the nucleus. However, these waves have just the right frequency to excite water molecules and thus produce heat – this is how your microwave oven works. Therefore it is thought that the principal risk of THz radiation is caused by heat-related damage.
Recent theoretical studies have shown that these pulses of THz radiation applied in picosecond duration may actually directly affect the DNA structure. It does so by amplifying the natural vibrations of hydrogen bonds that are essential in bonding the two strands of the double helix structure together and as a result, forming “bubbles” and openings in the DNA strand. This brings about the question “Is it possible for THz pulses to break DNA strands?” There have been earlier animal cell culture studies that shows THz radiation may very well directly affect biological function under specific conditions like pulse duration and exposure time.
In this first-of-its-kind study, the Canadian researchers have been able to reveal the effects of THz radiation on the DNA structure by using a marker known as phosphorylated H2AX. On the flip side, they have shown that THz radiation actually has an ability to increase the levels of tumor suppressors and cell-cycle regulatory proteins that help with DNA repair. This suggests that intense picosecond THz radiation damage to the DNA in human skin may be quickly repaired and ultimately minimizes the risk of carcinogenesis. The skin sample that was used is a living culture of cells which were undergoing mitosis during the THz experiment.
“The increase in the amount of phosphorylated H2AX in tissues exposed to intense THz pulses compare to the unexposed controls indicated that DNA double strand breaks were indeed induced by intense THz pulses,” observed Titova. Once DNA breaks occur, they can eventually lead to tumors if unrepaired. “This process is very slow and cells have evolved many effective mechanisms to recognize damage, pause cell cycle to allow time for the damage to be repaired, and – in case repair is unsuccessful – to prevent damage accumulation by inducing apoptosis, which is programmed cell death of the affected cell”.
The Canadian researchers hope to explore the potential therapeutic effects of intense THz radiation exposure to see whether or not such treatment may be the new primary tool to fight cancer.
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