International research: Where exactly does the electric current in a DNA molecule go?

A study published in Nature Nanotechnology, led by Prof. Danny Porat of the Hebrew University, demonstrates for the first time that a significant electric current travels long distances in DNA molecules. The researchers were surprised to find that the electrical conduction passes through the DNA backbone, which was considered an unlikely transmission channel. The discovery is currently being used as a basis for developing a detector that can sensitively and quickly detect markers for cancer and even the corona virus.

Technological developments in recent decades have increased the need to manufacture tiny chips and electronic components to create powerful computing power in less storage space. So far, it has been minimized with traditional technological tools in the world of computing, but continuing that trend of minimizing requires thinking outside the box. New directions have led researchers to turn back to “Mother Nature,” which it turns out that even in the nanoscale world teaches us a thing or two, such as the desire to use DNA to develop electrical devices.

To date, the scientific community has established the hypothesis that an electric current can pass through DNA molecules, but no unequivocal experiment has ever been conducted in which a relatively high current is measured over a large distance in a single double-stranded DNA molecule, accurately explaining the conduction mechanism. For the past twenty years the accepted paradigm has been that the electric current passes through the DNA bases that bind the two coils. However, the results regarding the conduction mechanism were not unequivocal and in some cases even contradicted the possibility that current could pass through the DNA molecule.

In an article published a few days ago In the prestigious journal “Nature Nanotechnology”, Led by an international team of scientists led by researchers from the Hebrew University Prof. Danny Porat from the Institute of Chemistry and the Center for Nanoscience and Nanotechnology, was able for the first time to measure a significant electric current conduction in a single and relatively long double-stranded molecule of DNA, And explain the mechanism behind conduction. The success of locating and identifying individual molecules between electrodes and measuring electrical currents in individual DNA molecules has allowed researchers to show that contrary to the paradigm that has dominated for about 20 years, most current passes through the DNA backbone (the outer part of the double helix). The uniqueness of this method is the degree of reliability, experimental apartments and stability that enabled a wide range of experiments to be performed, from which it is possible to learn about the conduction properties of DNA and understand the conductivity mechanism.

According to Prof. Porat, “We faced a number of difficult technical challenges and after overcoming them we were able to carry out this controlled experiment. We were able to measure significant currents in relatively long DNA molecules and show that the conduction mechanism is different from what has been assumed in the scientific community so far. The main challenge was to be able to make sure that each experiment sampled a single DNA molecule and measured it over time. “After many attempts, a very talented student, Roman Jurbel, succeeded in developing a technique for the stable connection of a single molecule to the contacts.”

Thanks to the variety of electrical measurements, we understood that the electric current that passes through DNA is not affected by changes in the base series of the molecule (in DNA, the cells of the base series determine the genetic code). The obvious conclusion was that the electric current passes through the external spine of the DNA, the structure common to all the molecules whose base series were different. Prof. Porat further explains. “In order to make sure that most of the current passes through the spine, we created interruptions in the spine itself on both sides of the double coil and we did see that in this case there was no current.”.

Beyond the important fact that the findings help in a basic understanding of the electrical conduction mechanisms in DNA, the insights gained from the research are already being used to develop electronic detectors that will be used, for example, for early detection of high-precision cancers and also For sensitive, efficient and fast detection of corona virus. Such a detector will take advantage of the fact that the current passes through the outer spine of the double coil. The detector will allow viral RNA to be sampled directly without the translation of DNA required for the methods.PCR The standards, Which can speed up And greatly simplify the discovery process “, Explains Prof. Porat.

Prof. Porat emphasizes that for him this is the greatest success of his career so far. At the academic level, we were able to put to the test a twenty-year-old common assumption and show that the electrical transmission mechanism in DNA passes through a spine that was considered an unreasonable transmission channel. There are many more questions that we will have to answer, but we have also taken another step at the engineering level towards the great ambition – to build electronic circuits based on DNA.

Moreover, the measurements now being published can form the basis for electronic devices such as switches and tiny transistors. In previous measurements published about six years ago, researchers were able to transmit an electric current over a large distance in complex molecules. From four strands of DNA On a hard surface (the study was also published in Nature Nanotechnology). These measurements were the basis for DNA-based conductive wires. “The combination of the two works could in the future enable the realization of complex electronic devices, on the basis of self-organization and cheap production,” Explains Prof. Porat.

The research is the result of several years of fruitful international academic collaboration. It was edited by Roman Jourbel under the guidance and direction of Prof. Porat and in collaboration with Prof. Alexander (Sasha) Kotliar of Tel Aviv University, and with researchers from Cyprus, Spain, the United States and India. In particular, it was edited in collaboration with and inspired by the late Prof. Yossi Sperling of the Weizmann Institute, and the article is dedicated to his memory.