Dual-quenching electrochemiluminescence system based on novel acceptor CoOOH@Au NPs for early detection of procalcitonin.

• CoOOH was used as the ECL quencher probe for the first time. • A new ECL-RET donor-receptor was proposed and fabricated for ultrasensitive detection of PCT. • Dual-quenching system was built to improve sensitivity. • NH 2 -MIL-101 conjugated with g-C 3 N 4 to increase its biocompatibility and emission performance. • The established immunosensor exhibited low detection limit of 3.4 fg mL−1 for PCT. Herein, an ultrasensitive electrochemiluminescence (ECL) biosensing platform for early diagnosis of procalcitonin (PCT) was developed based on enhancing the stability of ECL signal and dual-quenching strategies. In this proposal, in order to improve the deficient of luminescence signal stability of semiconductor luminescent materials, the chromophore graphitic carbon nitride (g-C 3 N 4) was loaded onto the MOF material (amine-functionalized MIL-101: NH 2 -MIL-101). Due to the excellent catalytic performance of NH 2 -MIL-101, more ECL reaction intermediate SO 4 - are restored from the co-reactant S 2 O 8 2-, thus the ECL signal of g-C 3 N 4 becomes stronger and more stable. With the aim of achieving detection of trace markers and improving sensor sensitivity, the dual-quenching strategy is carried out, which was achieved as follows: (i) the strong energy transfer between the donor of g-C 3 N 4 @NH 2 -MIL-101 and the acceptor of cobalt oxyhydroxide nanoflakes@gold nanoparticle (CoOOH@Au NPs) rational diminishes the ECL signal of g-C 3 N 4 ; (ii) the perfect spectral overlap with the luminescent matrix achieves efficiency quenching through resonance energy transfer (RET). Benefiting from the ultrastability of luminophore and the reasonable dual quenching effect, the fabricated ECL biosensor presented dominant stability, selectivity and reproducibility accompanied by detection ranges from 0.014 pg/mL to 40 ng/mL and extremely low detection limit of 3.4 fg/mL. Consequently, it is worth believing that this method can provide a potential analytical strategy for trace immunoassay in clinical analysis. [ABSTRACT FROM AUTHOR]