SERS increases in creases

06-22-2010: Wrinkles are not all bad news according to European scientists, who have used them to improve a spectroscopic technique used to identify molecules.

Luis Liz-Marzán and colleagues have developed a versatile method for making improved SERS substrates. They made a wrinkled strip of a silicon-based organic polymer called polydimethylsiloxane and pressed it into a gold nanoparticle solution on a glass slide. After the solvent had evaporated, they removed the wrinkled ‘stamp’ leaving parallel lines of gold nanoparticles. The gold arrays, per nanoparticle in the substrate, were at least twice as good at enhancing Raman signals compared to conventional SERS substrates, the group claims.

Surface-enhanced Raman spectroscopy (SERS) provides vibrational fingerprints of molecules by using a roughened metal surface (known as a SERS substrate) to enhance the Raman signal. However, because it is difficult to produce uniform SERS substrates, measurements are often irreproducible and so quantitative applications of this ultra-sensitive technique are limited.

Liz-Marzán says her team’s new technique could pave the way for the large scale development of highly sensitive quantitative SERS platforms.

Original publication: Nicolás Pazos-Pérez, Weihai Ni, Alexandra Schweikart, Ramón A. Alvarez-Puebla, Andreas Fery and Luis M. Liz-Marzán, Chemical Science 2010.