Abstract
A novel ternary composite of hemin-graphene-Au nanorods (H-RGO-Au NRs) with high electrocatalytic activity was synthesized by a simple method. And this ternary composite was firstly used in construction of electrochemiluminescence (ECL) immunosensor due to its double-quenching effect of quantum dots (QDs). Based on the high electrocatalytic activity of ternary complexes for the reduction of H2O2 which acted as the coreactant of QDs-based ECL, as a result, the ECL intensity of QDs decreased. Besides, due to the ECL resonance energy transfer (ECL-RET) strategy between the large amount of Au nanorods (Au NRs) on the ternary composite surface and the CdS:Eu QDs, the ECL intensity of QDs was further quenched. Based on the double-quenching effect, a novel ultrasensitive ECL immunoassay method for detection of carcinoembryonic antigen (CEA) which is used as a model biomarker analyte was proposed. The designed immunoassay method showed a linear range from 0.01 pg mL−1 to 1.0 ng mL−1 with a detection limit of 0.01 pg mL−1. The method showing low detection limit, good stability and acceptable fabrication reproducibility, provided a new approach for ECL immunoassay sensing and significant prospect for practical application.
Highlights
Sensitive and accurate detection of serum or tissue biomarkers becomes increasingly important in biomedical research, biodefense applications and early diagnosis of diseases[1,2,3,4]
A ternary complex Hemin-Reduced Graphene Oxide (H-RGO)-Au nanorods (Au NRs) was first synthesized and reported during our previous work[31] and recently we found that it showed excellent performance during ECL biosensing which has not been reported
We first presented a novel ultrasensitive ECL immunoassay method based on the high electrocatalytic activity of ternary complexes hemin-reduced graphene oxide-Au nanorods (H-RGO-Au NRs) for the reduction of H2O2 as the coreactant of quantum dots (QDs)-based ECL, and the ECL resonance energy transfer (ECL-RET) strategy between the abundant Au NRs on the graphene triple complex surface and the CdS:Eu−• to obtain an excited state (CdS):Eu QDs (Fig. 1)
Summary
Sensitive and accurate detection of serum or tissue biomarkers becomes increasingly important in biomedical research, biodefense applications and early diagnosis of diseases[1,2,3,4]. Another coreactant consumption probe enzyme mimics with high electrocatalytic reactivity and convenient storage and treatment attracted increasing interests Among these enzyme mimics, for the reason that graphene oxide (GO) provides large specific surface areas and other specific properties, it has been widely employed for construction of devices involving catalytic processes. We first presented a novel ultrasensitive ECL immunoassay method based on the high electrocatalytic activity of ternary complexes hemin-reduced graphene oxide-Au nanorods (H-RGO-Au NRs) for the reduction of H2O2 as the coreactant of QDs-based ECL, and the ECL resonance energy transfer (ECL-RET) strategy between the abundant Au NRs on the graphene triple complex surface and the CdS:Eu QDs (Fig. 1). Compared former reported material[33], this novel H-RGO-Au NRs showed many unique and interesting properties including large specific surface, with abundant Au NRs for ECL-RET and peroxidase-like activity, all of which were favorable conditions for ECL biosensor. The method provided a new approach for ECL immunoassay sensing and significant prospect for practical application
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