Dual-quenching electrochemiluminescence system based on resonance energy transfer from gold dendrite@polypyrrole core–shell nanoparticles enhanced g-C3N4 to ZnONFs@PDA-sCuO for procalcitonin immunosensing.

This work presents a dual-quenching electrochemiluminescence resonance energy transfer (ECL-RET) immunosensor on account of the double quenching effects of polydopamine coated ZnO nanoflowers (ZnONFs@PDA) loaded with small-sized copper oxide nanoparticles (sCuO), named ZnONFs@PDA-sCuO, towards gold dendrite@polypyrrole core–shell nanoparticles (AuD@PPy) enhanced g-C 3 N 4 (g-C 3 N 4 -AuD@PPy) for sensitive analysis of procalcitonin (PCT). To be specific, AuD@PPy with core-shell structure were loaded onto g-C 3 N 4 to enhance the emission performance of g-C 3 N 4. In addition, the ultraviolet absorption spectra of ZnONFs@PDA and sCuO showed considerable overlap with the ECL emission spectra of g-C 3 N 4 appropriately. So sCuO and ZnONFs@PDA were combined and designed as an efficient dual-quencher of ECL luminescence of g-C 3 N 4 by RET interaction. The biosensor showed superior linear detection range from 0.00005 to 50 ng mL−1, with a sensitive detection limit of 17.2 fg mL−1 (S/N = 3). It is worthy to note that a new type ECL-RET couple made up of g-C 3 N 4 -AuD@PPy (donor) and ZnONFs@PDA-sCuO (acceptor) was developed to construct a sandwich ECL biosensor for PCT detection. The studied immunosensor had satisfactory sensitivity, specificity and reproducibility, indicating the proposed sensing method could provide a good technical means and theoretical basis for the diagnosis of serious diseases. • A new ECL-RET donor-receptor was proposed and fabricated for ultrasensitive detection of PCT. • AuD@PPy nanocomposites with core-shell structure were loaded onto g-C3N4 to enhance the ECL emission performance. • ZnONFs@PDA-sCuO was firstly used as an efficient dual-quenching prober of ECL signal. • The designed immunosensor exhibited low detection limit of 17.2 fg mL-1 for PCT. [ABSTRACT FROM AUTHOR]