The surface-enhanced raman scattering signals (SERS) of four analytes, in low concentrations, have been detected using silver nanoparticles developed by scientists in China.

Ming-Wang Shao, Shuit-Tong Lee and colleagues from the Anhui Normal University and the City University of Hong Kong, in China, have developed an ultrasensitive method, where the SERS signals of four different analytes (rhodamine 6G, trinitrotoluene, bovine serum albumin and crystal violet) were observed at concentrations as low as 1 x 10^-16 M.

SERS is a useful technique that results in the enhancement of raman scattering signals from molecules that have been attached on to a metal surface. SERS have biomedical applications as they can be used to detect compounds in low-concentrations, which is ideal for bodily fluids, blood, tissue and dye molecules used for labeling molecules of biomedical interest.

Numerous methods to prepare SERS substrates are known, however, Shao showed that the silver nanoparticles (Ag NPs) can be prepared using beta-silver vanadate and copper as reactants. The resulting Ag NPs had an average diameter of 15 nm and had high quality crystallinity. The four analytes were chosen to demonstrate the ultrasensitive performance of the Ag NPs as a substrate for SERS.

'This technique might be employed to detect trace biomolecules or dangerous chemicals. However, the quantitative detection of the samples remains to be improved further and the enhancement mechanism needs further work,' said Shao.

Emma Shiells