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

Qing Zhu^a, Huixia Liu^a, Jing Zhang^c, Kang Wu^b,*（吴康）, Anping Deng^a*（邓安平）, Jianguo Li^a,*（李建国）

^aThe Key Lab of Health Chemistry & Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering & Materials Science, Soochow University, Suzhou 215123, China

^bSchool of Biology & Basic Medical Science, Soochow University, Suzhou 215123, China

^cShanghai Animal Disease Control Center, Shanghai 201103, China

Sensors and Actuators B243(2017) 121–129

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⁻¹and 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.

链接：http://www.sciencedirect.com/science/article/pii/S0925400516319335