Guanine-Decorated Graphene Nanostructures for Sensitive Monitoring of Neuron-Specific Enolase Based on an Enzyme-Free Electrocatalytic Reaction

• Published in: Analytical Sciences Vol. 29; no. 12; pp. 1195 - 1201
• Main Authors: LI, Guang-Zhou, TIAN, Feng
• Format: Journal Article
• Language: English
• Published: Singapore The Japan Society for Analytical Chemistry 2013; Springer Nature Singapore; Nature Publishing Group
• Subjects: Analytical Chemistry; bioelectrocatalytic reaction; Catalysis; Chemistry; electrochemical immunosensor; Electrochemical Techniques; Electrochemistry; Electrodes; Graphite - chemistry; Guanine - chemistry; Guanine-decorated graphene nanostructures; Humans; Immunoassay; Nanostructures - chemistry; neuron-specific enolase; Neurons - enzymology; Phosphopyruvate Hydratase - analysis; Phosphopyruvate Hydratase - metabolism; electrochemical immunosensor; bioelectrocatalytic reaction; Guanine-decorated graphene nanostructures; neuron-specific enolase
• ISSN: 0910-6340; 1348-2246; 1348-2246
• DOI: 10.2116/analsci.29.1195

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)32+ through the catalytic oxidation of Ru(bpy)32+ 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 3Sblank 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%.