Osaka, Japan – DNA holds the instructions that make us who we are. If we want to read those instructions, say to understand our predisposition to genetic disorders, we need to carefully 'unzip' DNA's iconic double-helix structure. This is neither easy nor fast, and the process involves intense heating and chemicals that can damage the DNA.
Now, in a new study published in ACS Nano, a research team led by The University of Osaka has developed a novel technology for making the unzipping process much easier. Their invention uses a miniature heater to precisely and gently unzip the DNA double helix.
The device uses a nano-sized platinum coil. As the DNA strand reaches the 'nanopore', a nano-sized hole on the device, voltage is applied to the coil. The heat opens the DNA, allowing one strand to be read at a time.
"A key advantage of the new method is that we don't have to heat the entire sample, only a very small part of it," explains lead author Makusu Tsutsui. "This means that the process needs only a few milliwatts of power, DNA damage is minimized, and we can read information from the DNA more accurately."
The team tested the new method using a long DNA molecule from a virus, which contained nearly 50,000 base pairs, as well as a smaller circular plasmid. A surprisingly small amount of heat was enough to unzip both the plasmid and the longer DNA molecule.
The team's precise heating method also allowed the team to control when and how the DNA molecule unzipped, regulate its speed and detect its passage through the nanopore using electrical signals. These detailed insights allowed the team to infer how the DNA molecule's movement is affected by electrical forces, viscous drag from the surrounding fluid and temperature, all of which are valuable data for further improvements to DNA sequencing.
"Our device should be easy to manufacture and, we hope, will become a core technology for fast and accurate next-generation sequencing," says senior author Tomoji Kawai. "The device is microscopic and consumes very little power, so it could potentially be incorporated into portable diagnostic devices, allowing on-site access to genetic information that can guide diagnosis and treatment."
The tiny, mighty heater-powered system represents a step toward handheld genetic testing devices, which could be used to quickly and easily determine the presence of genes responsible for cancer or other diseases. It could also help boost personalized medicine, allowing doctors to recommend treatments based on a person's unique genetic information.
