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.

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.…”

Fluorescent nanoparticles for chemical and biological sensing

“…Yang et al prepared Ru(II) doped silica NPs for the ECL determination [141]. Zhu et al fabricated poly(diallyldimethyl ammonium chloride)-protected grapheme-CdSe QDs composites for ECL immunosensing of human IgG (Figure 11) [142]. The ECL immunosensor has an extremely sensitive response to human IgG in a linear range of 0.02-2000 pg mL −1 with a detection limit of 0.005 pg mL −1 .…”

“…(B) Schematic illustration of the stepwise immunosensor fabrication process, including the formation of P-GR-CdSe composite film on the Au electrode, the linkage of PDDA to the film, the conjugation of gold NPs to PDDA, the immobilization of antibody (Ab) on the electrode via gold NPs, and the specific immunoreactions[142]. and is a key regulator of cell function.…”

Corrosion Resistance of the Superhydrophobic Mg(OH)2/Mg-Al Layered Double Hydroxide Coatings on Magnesium Alloys

“…The shoulder band at approximately 2931 cm −1 corresponds to a CO3 2− -H2O stretching vibration, suggesting the presence of water molecules hydrogen bonded to the carbonate ions present in the interlayer [35]. The bands at 2913 and 2861 cm −1 are attributed to C-H asymmetric and symmetric stretching vibrations [36]. The bands at 1465 cm −1 are attributed to the symmetric and asymmetric stretching modes of CO3 2− ion in the interlayer or introduced by CO2 in the air [37].…”