Research at One University Scales-Up Nanopore Sequencing Technology

By enabling the researchers to detect the occurrence of nucleobases, the platform can help advance the sensitivity of nanopore sequencing.

FREMONT, CA: Nanopore technology has the potential to empower the development of compact, portable, low-cost devices that can sequence deoxyribonucleic acid (DNA) in real-time. However, improving the accuracy of the technology has been one of the obstacles.

Researchers at one university have developed a nanopore sequencing technology that can identify the presence of nucleobases, the building blocks of ribonucleic acid and DNA, for the first time. Most DNA sequencing is done primarily in the lab, using fluorescent dye to prepare samples and lasers to identify the sequence of the four nucleobases, or fundamental units of the genetic code: adenine (A), guanine (G), cytosine (C), and thymine (T). When illuminated, each nucleobase emits a separate wavelength, allowing scientists to establish the sequence. By enabling the researchers to detect the occurrence of nucleobases, the platform can help advance the sensitivity of nanopore sequencing.

A DNA sample is uncoiled, and the hair-like strand is passed through a tiny hole, or nanopore, often in a manufactured membrane, in nanopore sequencing. The DNA strand intrudes the electrical current passing through the membrane as it passes through the nanopore. The current reacts differently depending on the size and shape of a DNA molecule. The electrical signal transitions as the DNA moves through the nanopore, and the characteristics of the DNA can be read by monitoring the signal.

The difficulty of controlling the pace of the DNA strand as it travels through the nanopore has been one of the hurdles in advancing nanopore sequencing. To solve this, the team created an atomically thin solid-state—or nonbiological—membrane coated with titanium dioxide, water, and an ionic liquid to reduce the speed of molecules passing through the membrane. The electrical impulses were amplified by adding water to the liquid solution, making them easier to interpret.

The researchers' next step will be to improve the platform to identify each nucleobase more quickly. Furthermore, the platform also opens the potential for sequencing other biomolecules.