A new device for immediate extraction of human DNA

A new device makes it possible to analyze a person's DNA and determine the sequence of its components in just 2 minutes, simply by taking a saliva sample.

Engineers from the University of Washington, in collaboration with a private company, also from Washington, NanoFactory, developed a device capable of extracting human DNA from liquid samples in a simpler, more efficient and more environmentally friendly way than existing methods. The new device will provide hospitals and research laboratories with an easier method for separating DNA from human fluid samples, thus helping in genome sequencing (determining the exact components of the genes), in diagnosing diseases and in DNA testing.

"Extracting DNA is a very complex task," explains Jae-Hyun Chung, a professor of mechanical engineering at the University of Washington, who was responsible for this study. "When we think about the existing methods, it can be compared to collecting hair with the help of a construction crane." The purpose of the new technology is to overcome such limitations. The device, produced as a small box-shaped kit, is ready for distribution to hospitals, clinics and laboratories. Separating DNA from body fluids is a cumbersome process that has become the bottleneck in the research of scientists in the fields of gene sequencing, especially for disease prevention and treatment. The market for DNA extraction alone reaches a turnover of 3 billion dollars per year. Extraction methods use a centrifuge to spin and separate DNA molecules, or filter from a liquid sample using a microfilter, but these methods take about half an hour and require the use of very toxic chemicals.

The engineers from the University of Washington developed microscopic detectors that are immersed in a liquid sample - saliva, phlegm or blood - while activating an electric field inside the liquid. This field causes the particles to concentrate around the surface of the tiny detector. Large particles hit the head of the detector and are deflected away from it, but molecules the size of DNA molecules stick to the detector and are captured on its surface. With the help of this technology, the DNA can be separated and purified within three minutes. "This simple process eliminates all the other steps required by the usual methods", explains the main researcher. The manual device can purify four separate liquid samples at the same time, and at the same time the technology can be adapted to provide the possibility of testing 96 samples at the same time, when this is the most common amount in laboratories that perform daily tests.
The tiny detectors, called microtips and nanotips, were developed and built at the University of Washington in a micromanufacturing facility capable of producing up to a million tips per year, a rate that is the key to proving that mass production is a possibility, explains the lead researcher.

Using the same method, the researchers also designed a device the size of a pencil that could be sent home with patients or provided to soldiers serving outside the country's borders. The patients will be able to take a saliva sample from their oral cavity, purify the DNA in it in an instant and send the results to the hospitals and laboratories to receive accurate results. This method could be particularly useful in the existing effort to determine the gene sequence of each and every person, an effort that will lead to an improvement in the prevention of diseases and their treatment, notes the lead researcher. The market for this type of device is not yet developed, but the research group claims that it will be ready and available when the market reaches the required demand. Meanwhile, the larger device (the one not the size of a pencil) is ready for commercialization and its developers have already started collaborating with the various vendors in this field.

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