Search

• A ternary ECL immunoassay based on ABEI is designed for amyloid-β protein detection. • Flower-like Co-MOFs with peroxidase-like activity is used as coreaction accelerator. • Co-MOFs not only act as nanocarriers of ABEI, but also catalyze H 2 O 2 decomposition. • The synergistic catalysis of Co-MOFs and Au NPs realize the ECL signal amplification. In this work, a "luminophore/coreactant/co-reaction accelerator" ternary electrochemiluminescence (ECL) system is proposed by using N -(aminobutyl)- N -(ethylisoluminol) (ABEI) functionalized cobalt-based MOFs (Co-MOFs/ABEI) with superior peroxidase-like activities as the luminophore. ABEI, the derivative of luminol, is used as the reductant and organic ligand to synthesize flower-like Co-MOFs/ABEI. The as-synthesized Co-MOFs/ABEI not only function as desirable nano-carriers for the enrichment of ABEI, but also act as co-reaction accelerators for the catalysis of H 2 O 2 decomposition. Furthermore, Au nanoparticles are decorated on Co-MOFs/ABEI via electrostatics attraction, endowing it with favorable biocompatibility and electrocatalytic property to bond with detection antibodies and generate more excited state ABEI*. Besides, with the advantages of large specific surface area and easy preparation, Au nanoparticles functionalized Fe 3 O 4 @polypyrrole is utilized to anchor the capture antibodies for immunoaction with target analyte. Amyloid-β protein (Aβ 42), a principal hallmark of Alzheimer's disease, is chosen as the target analyte. The proposed Aβ 42 immunosensor performs with a broad linear range from 10 fg mL−1 to 100 ng mL−1 and a detection limit down to 3 fg mL−1, opens up new prospects for clinical analysis of Aβ 42 and provides promising approaches to synthesize luminophore-functionalized MOFs with high luminous efficiency for ECL bioanalysis. [ABSTRACT FROM AUTHOR]

Highlights • A label-free ECL immunosensor was designed based on Ti doped BiOBr for NT-proBNP detection. • BiOBr was employed as ECL substrate and emitter to simplify the construction process. • The ECL property was further improved by functionalizing BiOBr with Ti and Au NPs. • Sensitive detection of NT-proBNP was achieved with good selectivity and stability. Abstract Heart failure is a serious medical condition and has become one of the world's biggest killers. N-terminal pro-B-type natriuretic peptide (NT-proBNP) has been recommended as a new biomarker of excellent prognosis-predictive ability for heart failure. Herein, a label-free electrochemiluminescence (ECL) immunosensor based on gold nanopariticles (Au NPs) functionalized Ti doped BiOBr (Ti:BiOBr-Au) is fabricated for the detection of NT-proBNP. Firstly, three-dimensional flower-like Ti doped BiOBr (Ti:BiOBr), which is firstly proposed with ECL property, is employed as both the ECL substrate and emitter to simplify the construction procedure. In the presence of K 2 S 2 O 8 , the formed Ti:BiOBr can generate stronger ECL signal than pure BiOBr. Due to the large specific surface area, Ti:BiOBr is functionalized with large amounts of Au NPs to further improve ECL emission. Under optimal experimental conditions, a linear response range for NT-proBNP detection from 0.001 ng mL−1 to 50 ng mL−1 is obtained with a detection limit of 0.33 pg mL−1. Featuring high sensitivity and excellent reproducibility, the proposed ECL immunosensor blazes a novel trail for the sensitive determination of NT-proBNP and other biomarkers. It is worth noting that Ti:BiOBr with stable ECL emission displays tremendous potential in ECL bioanalysis as a novel type of emitter candidates. [ABSTRACT FROM AUTHOR]

A novel label-free electrochemiluminescence (ECL) immunosensor was developed for the detection of Nuclear Matrix Protein 22 (NMP 22) based on the graphite-like carbon nitride (g-C 3 N 4 ) and gold nanoparticles (AuNPs). Graphite-like carbon nitride was firstly combined with AuNPs, which promoted the electrons transfer and enhanced the ECL intensity of g-C 3 N 4 largely. Then, anti-NMP 22 was immobilized onto the electrode through Au–NH 2 without the usage of crosslinking agents. The connection between AuNPs and antibody influenced the conductive performance of AuNPs, leading to some decrease of ECL intensity. Then, bovine serum albumin (BSA) solution was dropped on the surface to block nonspecific binding sites. Finally, after the specific immunoreaction between NMP 22 and anti-NMP 22, the ECL intensity decreased further, because the protein on the electrode hindered the diffusion of luminescent reagents and electrons toward the electrode surface. Therefore, a linear relation between ECL intensity and the logarithm of NMP 22 concentration was obtained from 50.0 pg mL −1 to 2.0 ng/mL ( R 2 = 0.988) with the detection limit of 10.0 pg mL −1 . The proposed ECL immunosensor provides a rapid, simple, and sensitive immunoassay strategy for protein detection, which might be promising for clinical application. [ABSTRACT FROM AUTHOR]

Abstract: A label-free electrochemiluminescence (ECL) immunosensor based on functionalized Santa Barbara Amorphous-15 (SBA-15) has been developed for detection of cancer antigen 15-3 (CA15-3). The functionalized SBA-15 was prepared by decoration of citrate-capped Ag nanoparticles and incorporation of Ru(bpy)3 2+on SBA-15. The Ag nanoparticles show remarkable enhancement effect on ECL properties of Ru(bpy)3 2+. In order to incorporate more Ru(bpy)3 2+, anionic surfactant sodium dodecyl sulfate (SDS) was used to increase the negative charge of the composite matrix. Chitosan–ionic liquid (CHIT–IL) were also used to increase the conductivity and film stability. The functionalized SBA-15 was used to label the anti-CA15-3 based on the covalent interaction between Ag nanoparticles and the amines of anti-CA15-3. The ECL immunosensor that used to detect breast cancer biomarker CA15-3 exhibits high ECL intensity, good biocompatibility and long-term stability. The results show that the ECL immunosensor has high sensitivity for CA15-3 with a linear range from 0.01U/mL to 100U/mL and a detection limit of 0.004U/mL (S/N=3). [Copyright &y& Elsevier]