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) immu-nosensor 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 den-drite@polypyrrole core-shell nanoparticles (AuD@PPy) enhanced g-C3N4 (g-C3N4-AuD@PPy) for sensitive analysis of procalcitonin (PCT). To be specific, AuD@PPy with core-shell structure were loaded onto g-C3N4 to enhance the emission performance of g-C3N4. In addition, the ultraviolet absorption spectra of ZnONFs@PDA and sCuO showed considerable overlap with the ECL emission spectra of g-C3N4 appropriately. So sCuO and ZnONFs@PDA 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-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 reproduc-ibility, indicating the proposed sensing method could provide a good technical means and theoretical basis for the diagnosis of serious diseases.

Automated summary

This work presents a dual-quenching electrochemiluminescence resonance energy transfer (ECL-RET) immunosensor for sensitive analysis of procalcitonin (PCT). The sensor utilizes polydopamine coated ZnO nanoflowers loaded with small-sized copper oxide nanoparticles to achieve double quenching effects, enhancing the emission performance of g-C3N4. The biosensor showed superior linear detection range and sensitive detection limit, providing a new technical means for the diagnosis of serious diseases.