Featured Research

from universities, journals, and other organizations

Both Shape And Size Matter In Tiny World Of Nanoparticles

Date:
December 3, 2001
Source:
Northwestern University
Summary:
Scientists at Northwestern University have created a nanoparticle with a new shape that could be a useful tool in the race to detect biological threats. The nanoprism, which resembles a tiny Dorito, exhibits unusual optical properties that could be used to improve biodetectors, allowing them to test for a far greater number of biological warfare agents or diseases at one time.

EVANSTON, Ill. — Scientists at Northwestern University have created a nanoparticle with a new shape that could be a useful tool in the race to detect biological threats. The nanoprism, which resembles a tiny Dorito, exhibits unusual optical properties that could be used to improve biodetectors, allowing them to test for a far greater number of biological warfare agents or diseases at one time.

The simple method used to produce triangular nanoprisms in large quantities, using commercially available silver nanospheres, soap and visible light, is reported in the Nov. 30 issue of the journal Science.

"Many detection systems are based on small particles and their individual properties," said Chad A. Mirkin, director of Northwestern’s Institute for Nanotechnology, who led the experimental portion of the study. "As we get more building blocks, the types of detectors one can build and the agents one can detect grow. With its intriguing optical properties, the nanoprism is a new and important building block for detection science. It’s a major new addition to our set of nanoscale Tinker Toys."

"The nanoprisms are a major fundamental advance because they have previously unidentified optical properties that derive from their unusual shape," said George C. Schatz, professor of chemistry, who led the theory part of the work. He and his team of researchers have used calculations to successfully model these properties and are excited about the prospects for using theory to guide the design of these novel nanomaterials for applications not only in detection but also in optics and electronics.

In nanotechnology, researchers are not proficient at making controlled shapes of materials; thus far, most of the bulk preparatory methods are for spheres and rods, added Mirkin. (A nanometer is one-billionth of a meter.)

The nanoprisms, made up of silver atoms, gives off a rich red color when exposed to light. The nanoparticles could be used as new diagnostic labels, lighting up when target DNA — of anthrax or HIV, for example — is present. By developing nanoprisms made of different materials and with varying shapes and sizes, a large number of multicolor diagnostic labels could become available.

Once the technology is optimized, biodetectors incorporating nanoprisms could be used to quickly, easily and accurately detect biological weapons such as anthrax, smallpox and tuberculosis, as well as a wide range of genetic and pathogenic diseases, from genetic markers for cancer and neurodegenerative diseases to HIV and sexually transmitted diseases.

In their experiments, the researchers found that when they placed common nanospheres made of silver in a solution containing soap molecules and irradiated the mixture with room light for three days, the spheres were converted into triangular prisms a mere 15 nanometers thick.

The light induced the nanospheres to break up into silver atoms, which then fed the growth of the nanoprisms, a process called ripening. The conversion process could be arrested at any point by stopping the light exposure, thus giving the researchers control over the shape and size of the nanoparticles.

"When you go from a sphere to a prism you get new properties — new optical properties, electrical properties, chemical properties and catalytic properties," said Mirkin, also George B. Rathmann Professor of Chemistry. "It’s the same material, but a different shape and size. And that makes all the difference."

In addition to biological diagnostics, development of the nanoprism in a wide variety of materials holds promise for electronics, materials, optics and catalysis.

Other authors on the paper are Rongchao Jin (lead author), YunWei Cao, K. L. Kelly and Gand J. G. Zheng, all of Northwestern. The research was supported by the National Science Foundation, Army Research Office and the Air Force Office of Scientific Research.


Story Source:

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


Cite This Page:

Northwestern University. "Both Shape And Size Matter In Tiny World Of Nanoparticles." ScienceDaily. ScienceDaily, 3 December 2001. <www.sciencedaily.com/releases/2001/12/011203060913.htm>.
Northwestern University. (2001, December 3). Both Shape And Size Matter In Tiny World Of Nanoparticles. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2001/12/011203060913.htm
Northwestern University. "Both Shape And Size Matter In Tiny World Of Nanoparticles." ScienceDaily. www.sciencedaily.com/releases/2001/12/011203060913.htm (accessed July 24, 2014).

Share This




More Matter & Energy News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) 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:
from the past week

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