Featured Research

from universities, journals, and other organizations

DNA and quantum dots: All that glitters is not gold

Date:
January 25, 2013
Source:
National Institute of Standards and Technology (NIST)
Summary:
Scientists have shown that by bringing gold nanoparticles close to the dots and using a DNA template to control the distances, the intensity of a quantum dot's fluorescence can be predictably increased or decreased. This breakthrough opens a potential path to using quantum dots as a component in better photodetectors, chemical sensors, and nanoscale lasers.

The NIST team explored the behavior of quantum dots and gold nanoparticles placed in different configurations on small rectangular constructs made of self-assembled DNA (see inset for photograph). Laser light (green) allowed the team to explore changes in the fluorescent lifetime of the quantum dots when close to gold particles of different sizes.
Credit: NIST

A team of researchers at the National Institute of Standards and Technology (NIST) has shown that by bringing gold nanoparticles close to the dots and using a DNA template to control the distances, the intensity of a quantum dot's fluorescence can be predictably increased or decreased. This breakthrough opens a potential path to using quantum dots as a component in better photodetectors, chemical sensors and nanoscale lasers.

Anyone who has tried to tune a radio knows that moving their hands toward or away from the antenna can improve or ruin the reception. Although the reasons are well understood, controlling this strange effect is difficult, even with hundred-year-old radio technology. Similarly, nanotechnology researchers have been frustrated trying to control the light emitted from quantum dots, which brighten or dim with the proximity of other particles.

The NIST team developed ways to accurately and precisely place different kinds of nanoparticles near each other and to measure the behavior of the resulting nanoscale constructs. Because nanoparticle-based inventions may require multiple types of particles to work together, it is crucial to have reliable methods to assemble them and to understand how they interact.

The researchers looked at two types of nanoparticles, quantum dots, which glow with fluorescent light when illuminated, and gold nanoparticles, which have long been known to enhance the intensity of light around them. The two could work together to make nanoscale sensors built using rectangles of woven DNA strands, formed using a technique called "DNA origami."

These DNA rectangles can be engineered to capture different types of nanoparticles at specific locations with a precision of about one nanometer. Tiny changes in the distance between a quantum dot and a gold nanoparticle near one another on the rectangle cause the quantum dot to glow more or less brightly as it moves away from or toward the gold. Because these small movements can be easily detected by tracking the changes in the quantum dot's brightness, they can be used to reveal, for example, the presence of a particular chemical that is selectively attached to the DNA rectangle. However, getting it to work properly is complicated, says NIST's Alex Liddle.

"A quantum dot is highly sensitive to the distance between it and the gold, as well as the size, number and arrangement of the gold particles," says Liddle, a scientist with the NIST Center for Nanoscale Science and Technology. "These factors can boost its fluorescence, mask it or change how long its glow lasts. We wanted a way to measure these effects, which had never been done before."

Liddle and his colleagues made several groups of DNA rectangles, each with a different configuration of quantum dots and gold particles in a solution. Using a laser as a spotlight, the team was able to follow the movement of individual DNA rectangles in the liquid, and also could detect changes in the fluorescent lifetime of the quantum dots when they were close to gold particles of different sizes. They also showed that they could exactly predict the lifetime of the fluorescence of the quantum dot depending on the size of the nearby gold nanoparticles.

While their tracking technique was time consuming, Liddle says that the strength of their results will enable them to engineer the dots to have a specific desired lifetime. Moreover, the success of their tracking method could lead to better measurement methods.

"Our main goals for the future," he concludes, "are to build better nanoscale sensors using this approach and to develop the metrology necessary to measure their performance."


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. Seung Hyeon Ko, Kan Du, J. Alexander Liddle. Quantum-Dot Fluorescence Lifetime Engineering with DNA Origami Constructs. Angewandte Chemie International Edition, 2013; 52 (4): 1193 DOI: 10.1002/anie.201206253

Cite This Page:

National Institute of Standards and Technology (NIST). "DNA and quantum dots: All that glitters is not gold." ScienceDaily. ScienceDaily, 25 January 2013. <www.sciencedaily.com/releases/2013/01/130125111356.htm>.
National Institute of Standards and Technology (NIST). (2013, January 25). DNA and quantum dots: All that glitters is not gold. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2013/01/130125111356.htm
National Institute of Standards and Technology (NIST). "DNA and quantum dots: All that glitters is not gold." ScienceDaily. www.sciencedaily.com/releases/2013/01/130125111356.htm (accessed October 23, 2014).

Share This



More Matter & Energy News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3D Printed Instruments Make Sweet Music in Sweden

3D Printed Instruments Make Sweet Music in Sweden

Reuters - Innovations Video Online (Oct. 23, 2014) Students from Lund University's Malmo Academy of Music are believed to be the world's first band to all use 3D printed instruments. The guitar, bass guitar, keyboard and drums were built by Olaf Diegel, professor of product development, who says 3D printing allows musicians to design an instrument to their exact specifications. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) 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