Fig. 3From: Rough surface Au@Ag core–shell nanoparticles to fabricating high sensitivity SERS immunochromatographic sensors a Schematic diagram of the SERS ICSs for detecting Cd2+. b Concentration dependent SERS spectra of the ICSs obtained from the precipitates that corresponded to different concentrations of Cd2+. The entire SERS spectra are shown in Additional file 1: Figure S24–38. c Calibration curve of SERS ICSs for the detection of Cd2+ Back to article page