Ultrasensitive detection of diclofenac in water samples by a novel surfaceenhanced Raman scattering (SERS)-based immunochromatographic assay using AgMBA@SiO2-Ab as immunoprobe
Diandian Denga, Hong Yangb, Chang Liua, Kang Zhaoa, Jianguo Lia, *（李建国）, Anping Denga, *（邓安平）
a The Key Lab of Health Chemistry & Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering & Materials Science, Soochow University, Renai Road 199, Suzhou 215123, China
b College of Pharmacy Sciences, Soochow University, Suzhou, 215123, China
Sensors & Actuators: B. Chemical 283 (2019) 563--570
In the last years, surface-enhanced Raman scattering based immunochromatographic assay (SERS-ICA) has been getting great attention and been applied for the detection of different target analytes. In this study, a novel SERSICA using AgMBA@SiO2-Ab as an immunoprobe has been developed for rapid, quantitative and ultrasensitive detection of a pharmaceutical diclofenac (DCF) residue in water samples. Ag, Ag@SiO2 and AgMBA@SiO2 nanoparticles (NPs) were synthesized and characterized. The immunoprobe was prepared by sandwiching the Raman reporter mercaptobenzoic acid (MBA) between the core-shell layers and immobilizing the monoclonal antibody (mAb) against DCF on the surface of the Ag@SiO2 NPs. Under optimal conditions, the sensitivity and limit of detection (LOD) of the SERS-ICA for DCF were found to be 9 pg mL−1 and 0.07 pg mL-1, respectively. The detection of the SERS-ICA for DCF was completed within 15 min. AgMBA@SiO2-Ab was stable within four months without significant loss of SERS intensity. The key to success of the SERS-ICA was the employment of the Ag@ SiO2 NPs as the SERS substrate, which possessed gorgeous SERS enhancement capability, predominant biocompatibility and excellent stability. This SERS-ICA is potential as an ultrasensitive analytical method in pointof- care testing, clinical diagnosis, food inspecting and environmental monitoring.