Simple SERS substrates: powerful, portable, and full of potential

Abstract

Surface enhanced Raman spectroscopy (SERS) is a powerful spectroscopic technique capable of detecting trace amounts of chemicals and identifying them based on their unique vibrational characteristics. While there are many complex methods for fabricating SERS substrates, there has been a recent shift towards the development of simple, low cost fabrication methods that can be performed in most labs or even in the field. The potential of SERS for widespread use will likely be realized only with development of cheaper, simpler methods. In this Perspective article we briefly review several of the more popular methods for SERS substrate fabrication, discuss the characteristics of simple SERS substrates, and examine several methods for producing simple SERS substrates. We highlight potential applications and future directions for simple SERS substrates, focusing on highly SERS active three-dimensional nanostructures fabricated by inkjet and screen printing and galvanic displacement for portable SERS analysis - an area that we believe has exciting potential for future research and commercialization.

Wafer-Scale Leaning Silver Nanopillars for Molecular Detection at Ultra-Low Concentrations

“…1 For applications that require massproduced SERS substrates, structures should also be robust, cost effective and involve few nanofabrication steps that are compatible with high volume manufacturing process flows. 21 From the nanofabrication point of view, the majority of produced SERS substrates are either based on (i) metallic nanoparticles in colloidal suspensions, or (ii) roughened metallic surfaces. Various shapes of metallic nanoparticles in colloidal solutions showing high EFs with tunable LSPR wavelengths have been synthesized and their optical properties have been investigated both experimentally and theoretically.…”

Evaluation and Optimization of Paper-Based SERS Substrate for Potential Label-Free Raman Analysis of Seminal Plasma

“…Paper-based SERS substrate not only has the advantages of low cost and ease of fabrication [8] but also demonstrates both high-sensitivity and great reproducibility [9,10], making it a facile platform for applications in fields such as forensic science, food safety, and environment protection [11][12][13]; particularly the unique properties of paper (e.g., flexibility, hydrophilicity) are wellsuited for analysis of samples with arbitrary shapes and trace level as well as those that cannot be easily transferred to lab. Printing nanoparticles directly onto the paper via commercial inkjet printer is a rapid and low-cost method for fabrication of paper-based SERS substrate [12,14].…”

Surface enhanced Raman spectroscopy (SERS) for in vitro diagnostic testing at the point of care

“…SERS is one technique that can enhance the Raman signal by several orders of magnitude by amplifying the electron cloud density around metallic nanostructures [99][100][101]. SERS signal enhancement is achieved through two distinct mechanisms: electromagnetic enhancement and chemical enhancement [100,[102][103][104]. For both mechanisms to occur simultaneously, an analyte must be adsorbed onto or reside very close to a dielectric (often metallic) surface [90].…”

“…Even when probing analytes such as MBA, DTNB, and BPE, which have aromatic rings (containing benzene) whose pi-bonds can be easily delocalized around the ring, producing distinct vibrational modes [97], the probability of a photon to be scattered inelastically is only ~1 in 10 8 [98]. SERS is one technique that can enhance the Raman signal by several orders of magnitude by amplifying the electron cloud density around metallic nanostructures [99][100][101]. SERS signal enhancement is achieved through two distinct mechanisms: electromagnetic enhancement and chemical enhancement [100,[102][103][104].…”