Dual-modal immunosensor with amine functionalized CoCu-embedded mesoporous ceria oxide nanoparticle with abundant oxygen vacancies for ultrasensitive detection of tetrabromobisphenol A

Abstract

A novel electrochemical (EC) sensing matrix was established for a sensitive immunoassay of tetrabromobisphenol A (TBBPA) by combining a competitive immunoreaction and dual signal output. In this study, a rod-like MnO 2 decorated reduced graphene oxide (rGO) supported Au hybrid (MnO 2 -rGO-Au) was utilized as a sensing platform to immobilize TBBPA antigens and thus label TBBPA antibodies, which were then combined with a CoCu-embedded mesoporous CeO 2 (CoCu-mCeO 2 ) catalytic probe with abundant oxygen. Remarkably, Co and Cu on the mesoporous CeO 2 (mCeO 2 ) exposed massive active sites that produced additional oxygen vacancies to ameliorate the electrocatalytic activity and redox performance of the mCeO 2 nanoparticle. Besides, CoCu-mCeO 2 acted as the secondary antibody conjugation label based on an amine functionalized bridge between mCeO 2 and the antibody and also improved the electrochemical performance. Under the optimized conditions, the fabricated immunosensor displayed: (i) a wide linear range for TBBPA detection, ranging from 0–243 ng/mL; (ii) lower detection limits of 0.034 ng/mL (according to the amperometric i - t method) and 0.076 ng/mL (calculated by differential pulse voltammetry method), respectively, which was lower than the enzyme-linked immunosorbent assay (ELISA) with a limit of detection (LOD) of 0.59 ng/mL; (iii) satisfactory accuracy and reliability (recoveries, 95%–126.2%; cyclic voltammetry (CV), 3.36%–8.9% measured by amperometric i - t method and recoveries, 95.4%–126%; CV, 3.49%–9.62% using DPV method). The designed immunosensor exhibited good sensitivity, accuracy, and excellent potential for trace TBBPA determination from various samples.