Receive industry and products news from the market categories that matter to you most.
Stay up to date on industry news and trends, product announcements and the latest innovations.
NIST publishes paper on gold nanostars.
Press Release Summary:
Oct 16, 2008 - Using surface-enhanced Raman spectroscopy, NIST scientists demonstrated that gold nanostars exhibit optical qualities that make them superior for chemical and biological sensing and imaging. Team tested optical properties using 2-mercaptopyridine and crystal violet molecules and found that Raman signal of 2-mercaptopyridine was 100,000 stronger when nanostars were present. Nanoparticles may one day be used in applications ranging from disease diagnostics to contraband identification.
Original Press Release
Gold Nanostars Outshine the Competition
Press release date: Oct 14, 2008
SERS relies on metallic nanoparticles, most commonly gold and silver, to amplify signals from molecules present in only trace quantities. For these types of experiments, scientists shine laser light on an aqueous solution containing the nanoparticles and the molecule of interest and monitor the scattered light. The detailed characteristics of both the molecule and the nanoparticle affect the strength of scattered light, which contains an identifying fingerprint for the molecule known as its vibrational signature. With nanoparticles amplifying the signature, it is possible to detect a very low concentration of molecules in a solution.
The NIST team tested the optical properties of the nanostars using two target molecules, 2-mercaptopyridine and crystal violet. These molecules were selected because of their structural similarity to biological molecules and their large number of delocalized electrons, a characteristic that lends itself to SERS. NIST researchers found that the Raman signal of 2-mercaptopyridine was 100,000 stronger when nanostars were present in the solution. The stars were also shown to be particularly capable of enhancing the signature of crystal violet, delivering a signal about 10 times stronger than the previous winner, nanorods. Both the nanostars and the nanorods outperformed the nanospheres commonly used for Raman enhancement.
NIST physicist Angela Hight Walker and her team perfected the process for making gold nanostars, building them from the bottom-up using surface alterations to manipulate their growth and control their shape. Once suspended in a solution, the team guided the nanostars to gather together to form multiple "hot spots," where the enhancement is dramatically larger than for a single nanostar.
According to Hight Walker, the fact that they can now be created en masse and have desirable optical properties should prompt researchers to examine their possible applications, perhaps eventually making them the stars of the nanoworld.
* E. Nalbant Esenturk and A. R. Hight Walker. Surface-enhanced Raman scattering spectroscopy via gold nanostars. Journal of Raman Spectroscopy, published online Sept. 24, 2008, DOI: 10.1002/jrs.2084.
Edited on Oct. 15, 2008, to correct caption.
Don't miss the latest news!