Assessing Metal Nanofabricated Substrates for Surface-Enhanced Raman Scattering (SERS) Activity and Reproducibility

Abstract

Surface-enhanced Raman spectroscopy (SERS) has been shown to be an effective technique for increasing the detection sensitivity in chemical and biological applications. SERS has a distinct advantage over normal Raman spectroscopy, with enhancements typically greater than 104 over the normal Raman signal; however, this advantage in sensitivity comes with a caveat: controlling the spectroscopic reproducibility and enhancement activity of metal nanostructured substrates can be difficult. We present a survey and subsequent data analysis performed on several nanostructured substrates designed for SERS, including silver and gold colloids, silver nanorods, gold nanoshells, and commercially manufactured gold nanostructures.

Methodologies for assessment of limit of detection and limit of identification using surface-enhanced Raman spectroscopy

“…Although not tested herein, one should be aware of other ways of sample administration, for example, by immersing the substrate in a liquid of known concentration of the analyte [22,32]. However, the available sample volumes were insufficient for this approach.…”

Gold sputtered Blu-Ray disks as novel and cost effective sensors for surface enhanced Raman spectroscopy

“…Unfortunately, the complexity brought about by the many factors that influence the observed SERS spectrum has hindered the development of SERS as a tool for quantitative analysis, as it is difficult to reproducibly control spectroscopic reproducibility and enhancement activities of the metal nanosubstrates 13 . However, recent and significant progresses in nano-science and technology have enabled fabrication of reproducible SERS nanostructured substrates which can be optimized for the excitation wavelength and target analyte, by a variety of self-assembly (bottom up) or directed assembly (top down) techniques [9][10][11][12][14][15][16][17] .…”

“…However, recent and significant progresses in nano-science and technology have enabled fabrication of reproducible SERS nanostructured substrates which can be optimized for the excitation wavelength and target analyte, by a variety of self-assembly (bottom up) or directed assembly (top down) techniques [9][10][11][12][14][15][16][17] . Although these substrates provide better results, they are expensive, require advanced manufacturing processes, and many are still not consistent enough 12,13,18,19 . A commonly used industry standard SERS substrate, Klarite TM , is prepared by nanofabrication of a highly regular array of 1.5 μm diameter inverted pyramids (depth 1.0 μm, pitch 2 μm) etched into silicon.…”

Maximum discrimination approach for classification of nearly identical signatures

“…This can be done by using a iterative median filter. 3 The result of doing so leads to the spectra with their baselines removed as shown in Figure 2.…”