Portable smart films for ultrasensitive detection and chemical analysis using SERS and SERRS

Abstract

Metallic nanostructures, much smaller than the wavelength of visible light, which support localized surface plasmon resonances, are central to the giant signal enhancement achieved in surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS). Plasmonic driven SERS and SERRS is a powerful analytical tool for ultrasensitive detection down to single molecule detection. For all practical SERS applications a key issue is the development of reproducible and portable SERS-active substrates, where the most widely used metals for nanostructure fabrication are silver and gold. Here, we report the fabrication of a smart film, containing gold nanoparticles (AuNPs), produced by in situ reduction of gold chloride III (Au+3) in natural rubber (NR) membranes for SERS and SERRS applications. The composite films (NR/AuNP membranes) show characteristic plasmon absorption of Au nanostructures, which notably do not influence the mechanical properties of the NR membranes. The term smart film has to do with the fact that the SERS substrate (smart film) is flexible and standalone, which allows one to take it anywhere and to dip it into solutions containing the analyte to be characterized by SERS or SERRS technique. Besides, the synthesis of the AuNPs at the surface of NR films is much simpler than making an Au colloid and cast it onto a substrate surface or preparing an Au evaporated film. Copyright (c) 2012 John Wiley & Sons, Ltd.