Facile Synthesis of an Economic 3D Surface-Enhanced Raman Scattering Platform for Ultrasensitive Detection of Antibiotics

Recently, surface-enhanced Raman spectroscopy (SERS) has attracted extensive concern of domestic and international researchers owing to the enormous signal amplification and unparalleled detection capability. However, developing the multifunctional SERS substrate materials through one facile way still remains a great challenge today. Herein, a novel dual functional sponge-based three-dimensional (3D) platform (AgNPs/PDA/MS) with both the ultra-sensitive SERS activity and enrichment effect on probes was synthesized easily for the first time. The 3D substrate possessed an ultra-low limit of detection (LOD) of 10−14 M, high enhancement factor (EF, 5.30 × 1010), and excellent enhancement uniformity (relative standard deviation, RSD = 3.515%) for methylene blue (MB). Moreover, it was successfully applied in the detection of ciprofloxacin (CIP) and enrofloxacin (ENR) antibiotics solutions at the low concentration, which exhibited the LODs of 0.351 and 0.359 ppb, respectively. More strikingly, the linear correlation between Raman intensities and the concentrations of CIP (R2 = 0.9827) and ENR (R2 = 0.9788) indicates the substrate has potential in quantitative SERS analyses. Thus, AgNPs/PDA/MS SERS substrate is of great significance to sensitively detect antibiotics and presents the practical application potential in food safety and environmental protection.