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 ([email protected]) loaded with small-sized copper oxide nanoparticles (sCuO), named [email protected], towards gold [email protected] core–shell nanoparticles ([email protected]) enhanced g-C3N4 (g-C3N4[email protected]) for sensitive analysis of procalcitonin (PCT). To be specific, [email protected] with core-shell structure were loaded onto g-C3N4 to enhance the emission performance of g-C3N4. In addition, the ultraviolet absorption spectra of [email protected] and sCuO showed considerable overlap with the ECL emission spectra of g-C3N4 appropriately. So sCuO and [email protected] were combined and designed as an efficient dual-quencher of ECL luminescence of g-C3N4 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-C3N4[email protected] (donor) and [email protected] (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.