Featured Research

from universities, journals, and other organizations

Speed of single-molecule measurements greatly increased

Date:
March 18, 2012
Source:
University of Pennsylvania
Summary:
Engineers have devised a way to measure nanopores -- tiny holes in a thin membrane that can detect single biological molecules such as DNA and proteins -- with less error than can be achieved with commercial instruments. They've miniaturized the measurement by designing a custom integrated circuit using commercial semiconductor technology.

This is a photograph of the Columbia Engineering team's custom multichannel CMOS preamplifier chip, attached to a circuit board with thin gold wirebonds.
Credit: Columbia Engineering

As nanotechnology becomes ever more ubiquitous, researchers are using it to make medical diagnostics smaller, faster and cheaper in order to better diagnose diseases, learn more about inherited traits and more. But as sensors get smaller, measuring them becomes more difficult; there is always a tradeoff between how long any measurement takes to make and how precise it is. And when a signal is very weak, the tradeoff is especially big.

Related Articles


Marija Drndić, an associate professor in the Department of Physics and Astronomy in the University of Pennsylvania School of Arts and Sciences, worked with a team of researchers at Columbia University's engineering school, led by Ken Shepard, to figure out a way to measure using nanopores, tiny holes in a thin membrane that can detect single biological molecules such as DNA and proteins, with less error than can be achieved with commercial instruments.

Their research was published in the journal Nature Methods.

Scientists are interested in nanopores because they may lead to extremely low-cost and fast DNA sequencing. But the signals from nanopores are very weak, so it is critically important to measure as cleanly as possible. In their study, the researchers miniaturized the measurement by designing a custom-integrated circuit using commercial semiconductor technology, building the nanopore measurement around the new amplifier chip.

"While most groups are trying to slow down DNA, our approach is to build faster electronics," Drndić said. "We combined the most sensitive electronics with the most sensitive solid-state nanopores."

"We put a tiny amplifier chip directly into the liquid chamber next to the nanopore, and the signals are so clean that we can see single molecules passing through the pore in only one microsecond," said Jacob Rosenstein, a Ph.D. candidate in electrical engineering at Columbia and lead author of the paper. "Previously, scientists could only see molecules that stay in the pore for more than 10 microseconds."

Many single-molecule measurements are currently made using optical techniques, which use fluorescent molecules that emit photons at a particular wavelength. But, while fluorescence is very powerful, its major limitation is that each molecule usually produces only a few thousand photons per second.

"This means you can't see anything that happens faster than a few milliseconds, because any image you could take would be too dim," Columbia Engineering's Shepard said. "On the other hand, if you can use techniques that measure electrons or ions, you can get billions of signals per second. The problem is that for electronic measurements there is no equivalent to a fluorescent wavelength filter, so, even though the signal comes through, it is often buried in background noise."

Shepard's group has been interested in single-molecule measurements for several years looking at a variety of novel transduction platforms. They began working with nanopore sensors after Drndic gave a seminar at Columbia Engineering in 2009.

"We saw that nearly everybody else measures nanopores using classical electrophysiology amplifiers, which are mostly optimized for slower measurements," Shepard said. "So we designed our own integrated circuit instead."

Rosenstein designed the new electronics and did much of the lab work. Drndić's group fabricated the nanopores that the team then measured in their new system.

"It's very exciting to be able to make purely electronic measurements of single molecules," Rosenstein said. "The setup for nanopore measurements is very simple and portable. It doesn't require a complicated microscope or high-powered instruments; it just requires attention to detail. You can easily imagine nanopore technology having a major impact on DNA sequencing and other medical applications within the next few years."

This research was funded by the National Institutes of Health, the Semiconductor Research Corporation and the Office of Naval Research.


Story Source:

The above story is based on materials provided by University of Pennsylvania. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jacob K Rosenstein, Meni Wanunu, Christopher A Merchant, Marija Drndic, Kenneth L Shepard. Integrated nanopore sensing platform with sub-microsecond temporal resolution. Nature Methods, 2012; DOI: 10.1038/nmeth.1932

Cite This Page:

University of Pennsylvania. "Speed of single-molecule measurements greatly increased." ScienceDaily. ScienceDaily, 18 March 2012. <www.sciencedaily.com/releases/2012/03/120318143912.htm>.
University of Pennsylvania. (2012, March 18). Speed of single-molecule measurements greatly increased. ScienceDaily. Retrieved October 26, 2014 from www.sciencedaily.com/releases/2012/03/120318143912.htm
University of Pennsylvania. "Speed of single-molecule measurements greatly increased." ScienceDaily. www.sciencedaily.com/releases/2012/03/120318143912.htm (accessed October 26, 2014).

Share This



More Matter & Energy News

Sunday, October 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
Real-Life Transformer Robot Walks, Then Folds Into a Car

Real-Life Transformer Robot Walks, Then Folds Into a Car

Buzz60 (Oct. 24, 2014) Brave Robotics and Asratec teamed with original Transformers toy company Tomy to create a functional 5-foot-tall humanoid robot that can march and fold itself into a 3-foot-long sports car. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Police Testing New Gunfire Tracking Technology

Police Testing New Gunfire Tracking Technology

AP (Oct. 24, 2014) A California-based startup has designed new law enforcement technology that aims to automatically alert dispatch when an officer's gun is unholstered and fired. Two law enforcement agencies are currently testing the technology. (Oct. 24) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins