Ultrasensitive QDs based electrochemiluminescent immunosensor for detecting ractopamine using AuNPs and Au nanoparticles@PDDA-graphene as amplifier

Qing Zhu, Huixia Liu, Jing Zhang, Kang Wu, Anping Deng, Jianguo Li
Sens. Actuators, B, 2017, 243, 121 - 129
Analyte Technique



electrochemiluminescence (ECL)

immunoassay, competitive binding

Subject category(s): General analytical chemistry; Sensors; Environment, agriculture and food; Agrochemicals; Animal feed

In this work, gold nanoparticals (AuNPs) and CdSe QDs decorated poly (diallyldimethylammonium chloride)-graphene (CdSe QDs/PDDA-GN/AuNPs) were prepared and applied as probe to assemble an electrochemiluminescence (ECL) immunosensor for detecting ractopamine (RAC) for the first time. The CdSe QDs/PDDA-GN/AuNPs composite showed good electronic conductivity, fast response and satisfactory stability which employed for fabricating ECL biosensors with high sensitivity. AuNPs and PDDA-GN were creatively applied in this sensor not only accelerate electron conduction to achieve dual signal amplification, but also provide large surface for coating antigen and antibody loading. A competitive immunoassay strategy was chosen for determining RAC, where RAC in the sample would compete with the coating antigen for the limited biomarkers. The well-prepared ECL immunosensor satisfied in samples detection of RAC with a wider linear range from 0.01 to 1000 ng mL−1 and a lower detection limit of 2.6 pg mL−1 (S/N = 3). The proposed ECL immunosensor displayed high sensitivity and stability, and provided an approach for determining other important biomarkers.

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