Surface-Enhanced Raman Spectroscopy Chips Based on Silver Coated Gold Nanostars

Surface-enhanced Raman scattering (SERS) is becoming widely used as an analytical tool, and the search for stable and highly responsive SERS substrates able to give ultralow detection of pollutants is a current challenge. In this paper we boosted the SERS response of Gold nanostars (GNS) demonstrating that their coating with a layer of silver having a proper thickness produces a 7-fold increase in SERS signals. Glass supported monolayers of these GNS@Ag were then prepared using simple alcoxyliane chemistry, yielding efficient and reproducible SERS chips, which were tested for the detection of molecules representative of different classes of pollutants. Among them, norfloxacin was detected down to 3 ppb, which is one of the lowest limits of detection obtained with this technique for the analyte.

Automated summary

This paper explores the use of surface-enhanced Raman scattering (SERS) as an analytical tool and demonstrates the enhancement of SERS response by coating gold nanostars (GNS) with a layer of silver. The resulting SERS chips, prepared using a simple chemistry technique, showed high efficiency and reproducibility in detecting various classes of pollutants. Notably, the detection limit for norfloxacin was as low as 3 ppb, one of the lowest limits achieved with this technique for the analyte.