Plasmonic nanogrooves for SERS sensing by 3D printing

Abstract

Surface enhanced Raman scattering (SERS) spectroscopy is a widely used analytical technique for detecting chemicals or biological molecules with high sensitivity and high specificity. Enhancing the sensitivity and lowering the detection limits are always the working direction of this research field. Furthermore, direct detection of low-concentration molecules in liquids remains a big challenge. In this work, we construct a SERS device consisting of periodically arranged polylactic acid (PLA) lines that are coated with silver, where the PLA line array is produced by 3D printing technique. The plasmonic nanogroove within the gap between the two adjacent PLA lines is found to be the dominant mechanism for SERS detection. A maximum enhancement factor of 2.26 × 106 has been achieved for the plasmonic nanogroove, with respect to a pure planar glass substrate. A detection limit of lower than 0.5 ppm has been research for such a sensor device in the direct detection of melamine in its aqueous solution. Furthermore, the PLA lines have advantages of biodegradability, biocompatibility, low costs, and thermo-plasticity, making the device environmentally friendly in potential applications in food safety inspection and pollutant detection in water.