title: Guanine-decorated graphene nanostructures for sensitive monitoring of neuron-specific enolase based on an enzyme-free electrocatalytic reaction.
abstract: A new and enzyme-free electrochemical immunoassay protocol was developed for the sensitive electronic monitoring of neuron-specific enolase (NSE) on a monoclonal mouse anti-human NSE antibody (mAb)-modified glassy carbon electrode, using guanine-decorated graphene nanostructures (GGN) as nanotags. To construct such an enzyme-free immunoassay format, guanine and polyclonal rabbit anti-human NSE antibody (pAb) were co-immobilized on the graphene nanostructures through the carbodiimide coupling. Based on a sandwich-type immunoassay mode, the assay was carried out in 0.1 M pH 7.4 PBS containing 5 μM Ru(bpy)3(2+) through the catalytic oxidation of Ru(bpy)3(2+) toward the guanine on the GGN. The presence of graphene nanostructures increased the immobilized amount of guanine, thus amplifying a detectable electronic signal. The covalent conjugation of guanine and pAb on the GGN resulted in a good repeatability and intermediate reproducibility down to 9.5%. Under optimal conditions, the dynamic concentration range of the developed immunoassay spanned from 0.005 to 80 ng mL(-1) NSE with a detection limit of 1.0 pg mL(-1) at the 3S(blank) level. In addition, the methodology was evaluated by assaying the spiking serum samples, and the relative standard deviation (RSD) between the electrochemical immunoassay and a commercialized enzyme-linked immunosorbent assay (ELISA) were 2.8-7.0%.
authors: Department of Sports and Health, Chongqing Three Gorges University.
authors: Guang-Zhou
authors: GZ
authors: Li
authors: Feng
authors: F
authors: Tian
mesh_terms: D002384:Catalysis; D055664:Electrochemical Techniques; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay; D049329:Nanostructures / Q000737:chemistry*; D009474:Neurons / Q000201:enzymology*; D010751:Phosphopyruvate Hydratase / Q000032:analysis* / Q000378:metabolism
chemical_list: D006147:Guanine; D006108:Graphite; D010751:Phosphopyruvate Hydratase