Ultrasensitive and Quantitative Detection of a New β-Agonist Phenylethanolamine A by a Novel Immunochromatographic Assay Based on Surface-Enhanced Raman Scattering (SERS)

Abstract

Phenylethanolamine A (PA) is a new kind of β-agonist, which was illegally used as a feed additive for growth promotion in China. In this study, a novel immunochromatographic assay (ICA) based on surface-enhanced Raman scattering (SERS) for the ultrasensitive and quantitative detection of phenylethanolamine A is presented. The principle of this new ICA is similar to that based on colloidal gold particles, but using Au(MBA)@Ag-Ab [e.g., polyclonal antibody of PA labeled Au@Ag core-shell nanoparticles (NPs) sandwiched with a Raman reporter (4-mercaptobenzoic acid, MBA)] as a probe. After ICA procedures, the specific Raman scattering intensity of MBA on the test line was measured for quantitative detection of PA. This assay was completed within 15 min. The IC50 and limit of detection (LOD) values of the ICA for PA detection were 0.06 ng mL(-1) and 0.32 pg mL(-1), respectively, which were 1-3 orders of magnitude lower than those obtained by other immunoassays, indicating the ultrasensitivity of this ICA. There was no cross-reactivity (CR) of the assay with another three β-agonists (ractopamine, clenbuterol, and salbutamol), suggesting high specificity of the SERS-based ICA. A spiking experiment revealed that the recoveries of PA from pig urine samples were in range of 99.9- 101.2% with relative standard deviations (RSDs) of 3.6-5.8%. The results demonstrated that this SERS-based ICA was able to quantitatively detect PA in urine samples with high sensitivity, specificity, precision, and accuracy and might be a powerful method for the analysis of other target analytes in the food area.

Functionalized AuMBA@Ag Nanoparticles as an Optical and SERS Dual Probe in a Lateral Flow Strip for the Quantitative Detection of Escherichia coli O157:H7

“…Au MBA @Ag was used as labels in the SERS‐LFS to achieve quantitative detection. In addition, the SERS enhancement of Au MBA @Ag will affect the sensitivity of the LFS (M. Li et al., ). The SERS signal intensity of MBA is enhanced by the electromagnetic field between the gold core and silver shell, and the thickness of the silver shell was optimized to achieve Raman signals with ultrahigh intensity and reproducibility.…”

Nanoparticle-based lateral flow biosensors

“…Li et al (2014) reported the use of LFSs on SERS, using AuNPs covered with 4-mercaptobenzoic acid (a Raman reporter). Their experiments demonstrated the great precision of the technology, the high selectivity against the reporters and a really low limit of detection, 0.32 pg/mL.…”

Optical Nanoprobes for Ultrasensitive Immunoassay

“…Li et al presented a novel SERS-based immunochromatographic assay for the ultrasensitive quantitative detection of phenylethanolamine A (PA) ( Figure 8C). 59 To construct this system, a new probe was designed using Au/Ag core−shell nanoparticles labeled with polyclonal antibody against PA sandwiched with 4-mercaptobenzoic acid (MBA, a Raman reporter) (Au MBA @Ag-Ab). The test line contained immobilized PA−BSA conjugate, which was designed to compete with target PA in the sample solution for the anti-PA polyclonal antibody, whereas goat antirabbit IgG was immobilized on the control line.…”