Month: November 2013

Focusing Laser Light on Tiny Nanopores will Boost Accuracy of DNA Sequencing Method

The Opto-electrical effect can be used to control the passage of DNA molecules through nanopore sensors, thereby leading to more accurate sensing and sequencing of individual DNA molecules

Low-cost, ultra-fast DNA sequencing would revolutionize healthcare and biomedical research, sparking major advances in drug development, preventative medicine and personalized medicine. By gaining access to the entire sequence of your genome, a physician could determine the probability that you’ll develop a specific genetic disease or tolerate selected medications. In pursuit of that goal, Professor Amit Meller (BME) has spent much of the past decade spearheading a method that uses solid state nanopores: 2 – 5 nanometer-wide holes in silicon chips that read DNA strands as they pass through to optically sequence DNA molecules.

Now Meller and a team of researchers at the Technion and Boston University have discovered a simple way to improve the sensitivity, accuracy and speed of the method, making it an even more viable option for DNA sequencing or characterization of small proteins, such as Ubiquitin in their native, folded, state.

In the November 3 online edition of Nature Nanotechnology, the team demonstrated that focusing a low-power, commercially available green laser on a nanopore increases current near walls of the pore, which is immersed in salt water. As the current increases, it sweeps the salt water along with it in the opposite direction of incoming samples. The onrushing water, in turn, acts as a brake, slowing down the passage of DNA through the pore. As a result, the nanoscale sensors can get a higher-resolution read of the DNA as it crosses the pore, and identify small, proteins that could not previously be detected.

Meller: “The light-induced surface charge modulation phenomenon that we describe in this paper can be used to instantly switch on and off the “brakes” acting on individual biopolymers, such as DNA or proteins sliding through the nanopores. This critically enhances the sensing resolution of solid-state nanopores, and can be easily integrated in future nanopore based DNA sequencing and protein detection technologies”

Slowing down DNA is essential to DNA or RNA sequencing with nanopores, so that nanoscale sensors can make the right call on what’s passing through.

“The goal is to hold a base pair (of DNA nucleotides) in the nanopore’s sensing volume long enough to ‘call the base’ (i.e, determine if it’s an A, C, G or T),” said co-author Allison Squires (a Boston University student, who also worked at the Technion and fabricated nanopores in the study). “The signal needs to be sufficiently different for each base for sensors in the nanopore to make the call. If the sample proceeds through the sensing volume too quickly, it’s hard for the sensors to interpret the signal and make the right call.”

Meller and his team characterized the amount of increase in current under varying illumination in many different-sized nanopores. They next aim to explore in greater detail the mechanism underlying the increase in surface current when the green laser is applied to a nanopore, information that could lead to even more sensitivity and accuracy in DNA sequencing

 Review the latest edition of Technion FOCUS, including Technion innovation in China; student inroads to former US President Bill Clinton; the online learning revolution; and how to build an energy friendly formula race car.

Over twenty students from Yale University were hosted at Technion last week as part of the Global Network Week (GNW) program. GNW is an international program held for the first time at Technion. The event organizers, Professor Miriam Erez and Dr. Harry Yuklea from the Technion MBA program, said that as a result of the project’s overwhelming success, another event will be held in March.

GNW is a unique student exchange program that enables MBA students study at different MBA schools. This framework allows students from different schools to network at a week-long event that focuses on specific business topics and exposes them to other academic curricula. Technion is the first and only Israeli institute that is a member of this global network.

The GNW week at Technion was dedicated to the topic of “Startup Nation”. Apart from the Yale students, additional ten students from the Technion (studying at the Haifa Campus and Tel Aviv Branch), and six students from Spain, Mexico and China participated in the event. During this week, students were exposed to Israeli entrepreneurship and to the relationship between academic, industry and innovation. They heard seminars termed “Israel’s Innovative Culture,” “Capital and Innovation – the Israeli Model,” and “Serial High-Tech Entrepreneurs in Israel.” Vivian, a Chinese student from Yale, said that “Up until now, I only linked Israel with tension and conflicts, but this week I discovered a magical land, a country that is modern and multicultural, filled with warm, intelligent and inquisitive people.”

Oren Dvoskin, a student of Technion’s MBA program, said that, “This was an exciting and intensive week, in which we were given a wide prospective with respect to academics, entrepreneurship, strategy and financial aspects, and about inventors who went on to become entrepreneurs. I gained a better understanding of the importance for entrepreneurs to be capable of seeing the big picture, as well as continually validating their target audience who would be interested in the technology they are developing.”

“The principal logic of the program,” explains Dr. Yuklea, “is to impart to students that there is no such thing as a “secret recipe” for entrepreneurship, but that we can give them the ‘spices’ with which they can prepare their unique dish. All of this week’s participants were brilliant students, and I believe that the process they underwent showed them the complexity of entrepreneurial work as well as the important attributes that an entrepreneur requires beyond the knowledge that can be learned at a university.”

As part of Technion’s membership in the GNW network, six MBA students from the Technion travelled abroad: four students went to Yale University in the US, and two students travelled to Fudan University in China.