Fabrication of Graphene–Quantum Dots Composites for Sensitive Electrogenerated Chemiluminescence Immunosensing

Abstract

A novel strategy is reported for the fabrication of poly(diallyldimethylammonium chloride) (PDDA)-protected graphene-CdSe (P-GR-CdSe) composites. An advanced electrogenerated chemiluminescence (ECL) immunosensor is proposed for the sensitive detection of human IgG (HIgG) by using the as-prepared P-GR-CdSe composites. The P-GR-CdSe composite fi lm shows high ECL intensity, good electronic conductivity, fast response, and satisfactory stability, all of which holds great promise for the fabrication of ECL biosensors with improved sensitivity. After two successive steps of amplifi cation via the conjugation of PDDA and gold nanoparticles (GNPs) in the fi lm, high ECL intensity is observed. The ECL immunosensor has an extremely sensitive response to HIgG in a linear range of 0.02-2000 pg mL − 1 with a detection limit of 0.005 pg mL − 1 . The proposed sensor exhibits high specifi city, good reproducibility, and longterm stability, and may become a promising technique for protein detection.

Quantum Dots Based Electrochemiluminescent Immunosensor for Ultrasensitive and Specific Determination of Mercury (II) Ions Using Gold Nanoparticles and a Monoclonal Antibody

“…Antigen-antibody complex could obstruct ion diffusion and change electrical capacitance, and both factors would significantly af- fect the electrochemical impedance of electrodes during the formation of antigen-antibody complex. 24 That was consistent with the observed greatly increased R et value via the anchor of GNPs-antigen conjugates and BSA (curve c, d in Fig. 2A).…”

Highly sensitive electroluminescence immunoassay for Hg(II) ions based on the use of CdSe quantum dots, the methylmercury-6-mercaptonicotinic acid-ovalbumin conjugate, and a specific monoclonal antibody

“…After the modification with cysteamine and GLD in turn, the resulting electrode showed a higher resistance, which implied that cyteamine and GLD had been well immobilized on the electrode (curve b-c). Antigen-antibody complex could act as a layer disturbing ion diffusion and changing electrical capacitance, and both factors would significantly affect the electrochemical impedance of electrodes during the formation of antigen-antibody complex [30]. The observed greatly increased R et value via the anchor of CH 3 Hg-MNA-OVA and BSA further confirmed the suggestion and indicated these species did well immobilized in turn on the electrode (Fig.…”

Sulfur Regulated Boron Nitride Quantum Dots Electrochemiluminescence with Amplified Surface Plasmon Coupling Strategy for BRAF Gene Detection

“…(Ru­(bpy) 3 2+ -TPA, Φ ECL 5% as the standard). The ECL mechanisms of S-BN QDs were similar to other QDs, such as CdSe QDs, carbon NCs, Si NCs, and GQDs . The ECL mechanisms of the S-BN QDs were the formation of the excited state QDs* with the existence of the K 2 S 2 O 8 coreactant.…”