Bisphenol A detection using gold nanostars in a SERS improved lateral flow immunochromatographic assay

We report on the development of a new range-extended bisphenol A (BPA) detection method that uses a surface-enhanced Raman scattering lateral flow assay (SERS-LFA) binary system. The assay includes high-SERS-performance gold nanoparticles, i.e., 40 nm gold nanostars (GNSs) and 4-aminothiolphenol (4-ATP) as a Raman reporter. To demonstrate the performance of this SERS-LFA kit in BPA detection, we tested BPA stock solutions with concentrations ranging from 0.05 to 60 ppb. The GNSs were coated with 4-ATP and then anti-BPA antibody serving as a biorecognition reagent to acquire both visual and Raman signals after application in the BPA SERS-LFA kit. The limit of detection for the SERS signals was 0.073 ppb, which is 205 and 20 times more sensitive than those of visual intensity and color intensity quantifications, respectively. The range of quantification of the SERS signals was doubled that of color intensity quantification. The SERS-LFA binary kit successfully detected BPA and provided more accurate results over a broader concentration range (2-fold) than that of optical intensity.