Novel gold nanoparticles functionalized Mo-polydopamine hollow sphere as an efficient quencher in conjugated microporous polymer electrochemiluminescent system

Abstract

The construction of an electrochemiluminescence (ECL) biosensor achieving sensitive detection of cancer markers by improving the intensity of luminescent materials and the effect of quenchers is still under study. Herein, we designed an ECL sandwich immunosensor for sensitive detection of prostate specific antigen (PSA), which integrated gold nanoparticles functionalized Mo-polydopamine hollow sphere (Au@Mo-PDA, as a quencher) with platinum nanoparticles modified conjugated microporous polymer (Pt-CMP, as a luminophore) in the presence of triethanolamine (TEOA, as a coreactant). First, CMP with large specific surface area and high porosity was electropolymerized on glassy carbon electrodes (GCEs) employing carbazole-riched 2,6-di(9H-carbazol-9-yl) anthracene-9,10-dione as a precursor. Then, platinum nanoparticles were electrodeposited on CMP to construct a high initial ECL intensity system (signal on). Meanwhile, Pt-CMP with good biocompatibility could be used as a matrix to load a mass of prostate specific capture antibody (Ab1). When the Au@Mo-PDA labelled prostate specific detection antibody (Ab2) was introduced via sandwich immuno-reaction, the quantitative detection of PSA was realized by the quenching effect of Au@Mo-PDA since the quinone unit in Mo-PDA could annihilate the excited state of Pt-CMP* (signal-off). The proposed ECL system performs a good linearity to PSA concentration ranging from 10 fg mL−1 to 5 ng mL−1 with a low detection limit of 4.2 fg mL−1 and possesses high selectivity, stability and reproducibility. This work provides a versatile platform for the application of Mo-polydopamine based hollow sphere and conjugated microporous polymer in ECL biosensors.