High-sensitive electrochemiluminescent analysis based on co-reactive high-molecular polymer and dual catalysis to generate oxygen in situ

An intense cathodic electrochemiluminescence from carbon-nanosheets in situ grown on glassy carbon electrode and application in immunoanalysis via biometallization strategy

An intense cathodic electrochemiluminescence (ECL) is reported from a polarized glassy carbon electrode (GCE) in peroxydisulfate solution. After the polarization in 1 M Na2SO4 at the potential of - 3.7 V for 3 s, carbon nanosheets (C-NSs) were in situ grown on the surface of the GCE. Measured in 100 mM K2S2O8 solution, the ECL intensity of the GCE/C-NSs is 112-fold that of a bare GCE. The ECL spectrum revealed that the true ECL luminophore in the GCE/C-NSs-peroxydisulfate system is O2/S2O82- which is promoted by C-NSs. When Cu2+ was electrochemically enriched and reduced to Cu(0) on the catalytic sites of C-NSs, the ECL from GCE/C-NSs/Cu in K2S2O8 solution was decreased with increasing logarithmic concentration of Cu2+ in the range from 10 pM to 1 μM, with a limit of detection (LOD) of 3 pM. An immunoanalysis method is proposed via a biometallization strategy using CuS nanoparticles as the tags and carcinoembryonic antigen (CEA) as the model analyte. After the immune recognition in the microplate, the CuS tags in the immunocomplex were dissolved and the resultant Cu2+ was electrochemically enriched and reduced on the catalytic sites of C-NSs, quenching the ECL intensity of GCE/C-NSs-O2/S2O82- system. The proposed ECL immunoanalysis method was used to quantify CEA in actual serum samples with an LOD of 1.0 fg mL-1, possessing the advantages of simple electrode modification, high sensitivity and good reproducibility.

Ultrasensitive ECL aptasensing of kanamycin based on synergistic promotion strategy using 3,4,9,10-perylenetetracar-boxylic-l-cysteine/Au@HKUST-1

Herein, a sensitive and selective electrochemiluminescence (ECL) aptasensor was designed using Au@HKUST-1 as accelerator towards the perylene derivative (PTC-Cys)/peroxydisulfate (S₂O₈^2-) system for kanamycin (KAN) assay. Firstly, the PTC-Cys was prepared by covalently binding l-cysteine to 3,4,9,10-perylenete-tracarboxylic acid, which was acted as the luminophore. Then Au@HKUST-1could play the part of effective catalyst to accelerate the electrochemical reduction process of S₂O₈^2-to produce more sulfate radical anions (SO₄^•-), thus the ECL signal of the compound was noticeably raised by 2.4 times in comparison with that in which only luminophore and S₂O₈^2- are present, achieving signal amplification of the ECL system. In the presence of KAN, aptamer was pulled down from the sensing interface, achieving a considerable enhancement of ECL intensity in S₂O₈^2- solution. Upon the optimal condition, our proposed strategy can quantify the concentration of KAN from 1.0 × 10^-13 to 1.0 × 10^-8 M with low limit of detection of 4.2 × 10^-14 M (S/N = 3).Besides, our proposed ECL aptasensor exhibited excellent sensitivity, stability and specificity, and could be successfully applied to detect KAN in practical samples, which proved its potential to detect other antibiotics in food security.