Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rice develops nanosensor for precision chemical analysis

10.01.2003


Nanoshell sensor opens door for new methods to exam single molecules



Nanotechnology researchers at Rice University have demonstrated the ability to precisely control the electromagnetic field around nanoparticles, opening the door for chemical screening techniques that could allow doctors, life scientists and chemists to routinely analyze samples as small as a single molecule.

The research is detailed in the current issue of Applied Physics Letters. It builds upon a widely used method of molecular analysis called Raman spectroscopy and capitalizes on the tunable optical properties of metal nanoshells, a novel type of nanoparticle invented at Rice.


"This result is extremely important because it is the first time that anyone has actually designed and engineered a nanosensor specifically for obtaining chemical information," said nanoshell inventor Naomi Halas, the Stanley C. Moore Professor of Electrical and Computer Engineering. "There are widespread applications for this technology in environmental science, chemistry and biosensing, and it may have very important applications in the early detection of cancer."

Scientists commonly use spectroscopy to discern detailed information about everything from distant galaxies to individual molecules. By studying the spectrum of light that an object emits, scientists can decipher which elements are present in the sample, and in some cases, how those elements relate to one another. Raman spectroscopy, in particular, allows scientists to observe the vibrational states of molecules, giving clues about where and how much molecules bend, for example, and serves as a "fingerprint" for the identification of specific molecules that may be of interest, such as environmental contaminants or chemical or biological toxins.

Scientists have long known that they could boost the Raman light emissions from a sample by a million times or more by placing the sample next to small particles of metal called colloids. Scientists have even observed single molecules with this method, but they have never been able to precisely control the electromagnetic state of the metal colloids, so results and interpretations of such studies vary widely.

Rice’s research offers scientists a chance to precisely control "surface enhanced Raman scattering," or SERS. In the Rice experiments, Halas’s group was able to dramatically enhance the SERS effect, making it up to a billion times more powerful in some cases.

Similar in structure to a hard-shelled chocolate candy, nanoshells are layered colloids that consist of a core of non-conducting material covered by a thin metallic shell. By varying the thickness of the conducting shell, researchers in Halas’ group can precisely tune the electric and optical properties of nanoshells.

Nanoshells are so useful for enhancing SERS and for other applications because of their size and precise structure. Nanoshells are just slightly larger than the size of molecules, measuring just a few tens of nanometers, or billionths of a meter, in diameter. Tuning the properties of nanoshells gives Halas’ group the ability to exert new forms of precision control at the molecular level.

The SERS research is described in the Jan. 13 issue of Applied Physics Letters in a paper titled "Controlling the Surface Enhanced Raman Effect via the Nanoshell Geometry," by J.B. Jackson, S.L. Westcott, L.R. Hirsch, J.L. West and N.J. Halas. The paper is available online at http://ojps.aip.org/aplo/.

The research was funded by the National Science Foundation, the Robert A. Welch Foundation and the Army Research Office’s Multidisciplinary University Research Initiative.

Jade Boyd | EurekAlert!
Further information:
http://chico.rice.edu/
http://ojps.aip.org/aplo/.

More articles from Process Engineering:

nachricht Fraunhofer researchers develop measuring system for ZF factory in Saarbrücken
21.11.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

nachricht New manufacturing process for SiC power devices opens market to more competition
14.09.2017 | North Carolina State University

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Gecko adhesion technology moves closer to industrial uses

13.12.2017 | Information Technology

Columbia engineers create artificial graphene in a nanofabricated semiconductor structure

13.12.2017 | Physics and Astronomy

Research reveals how diabetes in pregnancy affects baby's heart

13.12.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>