Spectroscopy Since 1975

Partnership to develop novel SERS substrate

11 January 2022 | News
by Ian Michael
Schematic of the Nikalyte gold nanoparticle SERS substrate

Wasatch Photonics and Nikalyte Ltd have announced a partnership to facilitate evaluation and testing of a novel surface-enhanced Raman spectroscopy (SERS) substrate for trace detection of materials, with applications in narcotics, food safety, pharmaceuticals, environmental and biological analysis. SERS is a form of Raman spectroscopy in which the analyte of interest interacts with gold or silver nanostructures to significantly enhance the Raman signal. It enables Raman spectroscopy to be applied to the detection of trace quantities of potentially harmful or biologically relevant compounds.

Nikalyte Ltd, who supply nanoparticle coating equipment and services, has developed a new form of substrate for SERS analysis. It incorporates the ease of use of a solid SERS substrate with the reproducibility of liquid SERS at a cost-effective price point, thus overcoming previous limitations to widespread use of the SERS technique. Conventional wet-deposited SERS substrates offer convenient sample preparation in that they employ an absorbent pad mounted to a microscope slide, but often display significant spatial inhomogeneities, resulting in low signal reproducibility. SERS using colloidal gold nanoparticles in aqueous solution, in contrast, yields very reproducible signals, but requires handling of solutions that is not conducive to field use by non-experts.

The Nikalyte SERS substrate approach is unique in that it utilises gold nanoparticles generated and deposited in vacuum, ensuring that they are ultra-pure and highly uniformly distributed. As no chemicals are used in the synthesis of the nanoparticles, the SERS substrates are free of contamination, delivering superior sensitivity and specificity. These substrates are available for less than $10 at test quantities, and can be scaled for volume use.

Together, Nikalyte and Wasatch Photonics are evaluating the performance of these new SERS substrates for use in a variety of relevant applications. To date, the use of 785 nm and 830 nm excitation has been assessed for trace detection of a representative drug analyte, demonstrating a 1000× increase in the limit of detection using the Nikalyte SERS substrates. The results of this study have been published on the Wasatch Photonics website. Future work will focus on improving the limit of detection further, and on studies of other analytes relevant for promising SERS applications.

“Surface enhanced Raman is an exciting and rapidly growing field. We are very excited to be working with Wasatch Photonics to evaluate and develop our SERS technology and to push the limits of what current SERS sensors can offer”, said Dr Vicky Broadley, Nikalyte Sales and Marketing Director.

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