Nanopore technology shows promise for the development of small, portable and inexpensive devices capable of real-time DNA sequencing. One of the challenges, however, has been making the technology more precise.
Researchers at the University of Texas at Dallas have moved closer to this goal by developing a nanopore sequencing platform that, for the first time, can detect the presence of nucleobases, the building blocks of DNA and ‘RNA. The study was published online on February 11 and is featured on the back cover of the journal’s April print edition. Electrophoresis.
“By allowing us to detect the presence of nucleobases, our platform can help improve the sensitivity of nanopore sequencing,” said Dr. Moon Kim, professor of materials science and engineering and distinguished professor Louis Beecherl Jr. at the Erik Jonsson School of Engineering and Computer Science.
Currently, most DNA sequencing is done through a process that involves preparing laboratory samples with a fluorescent dye and using lasers to determine the sequence of the four nucleobases, the basic units of the genetic code: adenine (A ), cytosine (C), guanine (G) and thymine (T). Each nucleobase emits a different wavelength when illuminated, allowing scientists to determine the sequence.
In nanopore sequencing, a DNA sample is unwound and the hair-like strand is fed through a small hole, or nanopore, usually in a fabricated membrane. By moving through the nanopore, the DNA strand disrupts the electric current flowing through the membrane. Current reacts differently depending on the characteristics of a DNA molecule, such as its size and shape.
“The electrical signal changes as the DNA moves through the nanopore,” Kim said. “We can read the characteristics of DNA by monitoring the signal.”
One of the challenges in advancing nanopore sequencing has been the difficulty in controlling the speed of the DNA strand as it moves through the nanopore. Research by the UT Dallas team focused on solving this problem by making an atomically thin – or non-biological – solid-state membrane coated with titanium dioxide, water, and ionic liquid to slow down. the speed of molecules across the membrane. Water was added to the liquid solution to amplify the electrical signals, making them easier to read.
“By allowing us to detect the presence of nucleobases, our platform can help improve the sensitivity of nanopore sequencing.”
The next step for the researchers will be to advance the platform to identify each nucleobase faster. Kim said the platform also opens up possibilities for sequencing other biomolecules.
“The ultimate goal is to have a portable DNA sequencing device that is fast, accurate and can be used anywhere,” Kim said. “It would reduce the cost of DNA sequencing and make it more accessible.”
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Material provided by University of Texas at Dallas. Original written by Kim Horner. Note: Content can be changed for style and length.