%0 Journal Article %A Qi, Meng %A Zhang, Yin %A Cao, Chaomin %A Zhang, Mingxing %A Liu, Shenghua %A Liu, Guozhen %D 2016 %T Decoration of Reduced Graphene Oxide Nanosheets with Aryldiazonium Salts and Gold Nanoparticles toward a Label-Free Amperometric Immunosensor for Detecting Cytokine Tumor Necrosis Factor‑α in Live Cells %U https://acs.figshare.com/articles/journal_contribution/Decoration_of_Reduced_Graphene_Oxide_Nanosheets_with_Aryldiazonium_Salts_and_Gold_Nanoparticles_toward_a_Label-Free_Amperometric_Immunosensor_for_Detecting_Cytokine_Tumor_Necrosis_Factor_in_Live_Cells/3846564 %R 10.1021/acs.analchem.6b02353.s001 %2 https://acs.figshare.com/ndownloader/files/6014214 %K FT-IR %K XPS %K Reduced Graphene Oxide Nanosheets %K Label-Free Amperometric Immunosensor %K cytokine tumor necrosis factor-alpha %K enzyme-linked immunosorbent assay %K anti-TNF -α detection antibody %K UV %K BV -2 cells %K graphene oxides nanocomposites %K 4- aminophenyl phosphorylcholine %K TEM %K ELISA %K TNF -α %K surface %K PPC %K analyte TNF -α %K form Ab 2 %K label-free electrochemical immunosensor %K 50 mM phosphate buffer %K X-ray photoelectron spectra %X In this study, a label-free electrochemical immunosensor was developed for detection of cytokine tumor necrosis factor-alpha (TNF-α). First, AuNPs loaded reduced graphene oxides nanocomposites (RGO-ph-AuNP) were prepared, and then, a mixed layer of 4-carbxyphenyl and 4-aminophenyl phosphorylcholine (PPC) was modified to the surface of AuNPs for the subsequent modification of anti-TNF-α capture antibody (Ab1) to form the capture surface (Au-RGO-ph-AuNP-ph-PPC­(-ph-COOH)) for the analyte TNF-α with the antifouling property. For reporting the presence of analyte, the anti-TNF-α detection antibody (Ab2) was modified to the graphene oxides which have been modified with the 4-ferrocenylaniline through diazonium chemistry to form Ab2-GO-ph-Fc. Then, a sandwich assay was formed on gold surfaces for the quantitative detection of TNF-α based on the electrochemical signal of ferrocene. X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV–vis, and electrochemistry were used for characterization of the stepwise fabrications on the interface. The prepared electrochemical immunosensor was successfully used for the detection of TNF-α over the range of 0.1–150 pg mL–1. The lowest detection limit of this immunosensor is 0.1 pg mL–1 TNF-α in 50 mM phosphate buffer at pH 7.0. The fabricated immunosensor provided high selectivity and stability and can be used to detect TNF-α secreted by live BV-2 cells with comparable accuracy to enzyme-linked immunosorbent assay (ELISA) but with lower limit of detection. %I ACS Publications