Ultrasensitive detection of protein kinase activity based on the Au NPs mediated electrochemiluminescence amplification of S2O82−–O2 system

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.

Dual-ligand Eu-MOF/CuS@Au Heterostructure Array-based ECL Sensor for MiRNA-128 Detection in Glioblastoma Tissues

In this work, the dual-ligand lanthanide metal-organic framework (MOF)-based electrochemiluminescence (ECL) sensor was constructed for the detection of miRNA-128 in glioblastoma (GBM) diagnosis. The luminescent Eu-MOF (EuBBN) was synthesized with terephthalic acid (BDC) and 2-amino terephthalic acid (BDC-NH2) as dual-ligand. Due to the antenna effect, EuBBN with conjugated-π structure exhibited strong luminescent signal and high quantum efficiency, which can be employed as ECL nanoprobe. Furthermore, the novel plasmonic CuS@Au heterostructure array has been prepared. The localized surface plasmon resonance coupling effect of the CuS@Au heterostructure array can amplify the ECL signal of EuBBN significantly. The EuBBN/CuS@Au heterostructure array-based sensing system has been prepared for the detection of miRNA-128 with a wide linear range from 1 fM to 1 nM and a detection limit of 0.24 fM. Finally, miRNA-128 in the clinic GBM tissue sample has been analysis for the distinguish of tumor grade successfully. The results demonstrated that the dual-ligand MOF/CuS@Au heterostructure array-based ECL sensor can provide important support for the development of GBM diagnosis.

Gold nanoparticles decorated carbon nitride nanosheets as a coreactant regulate the conversion of the dual-potential electrochemiluminescence of Ru(bpy)32+ for Hg2+ detection

Dual-potential electrochemiluminescence of Ru(bpy)₃²⁺ for Hg²⁺ assay using Au–g-C₃N₄ NSs as on-electrode coreactant.