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 Intelligent wheelchairs, predictive prostheses
20.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA

nachricht Jelly with memory – predicting the leveling of com-mercial paints
15.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

'Lipid asymmetry' plays key role in activating immune cells

20.02.2018 | Life Sciences

MRI technique differentiates benign breast lesions from malignancies

20.02.2018 | Medical Engineering

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>