title: An electrochemically reduced graphene oxide-based electrochemical immunosensing platform for ultrasensitive antigen detection.
abstract: We present an electrochemically reduced graphene oxide (ERGO)-based electrochemical immunosensing platform for the ultrasensitive detection of an antigen by the sandwich enzyme-linked immunosorbent assay (ELISA) protocol. Graphene oxide (GO) sheets were initially deposited on the amine-terminated benzenediazonium-modified indiun tin oxide (ITO) surfaces through both electrostatic and π-π interactions between the modified surfaces and GO. This deposition was followed by the electrochemical reduction of graphene oxide (GO) for preparing ERGO-modified ITO surfaces. These surfaces were then coated with an N-acryloxysuccinimide-activated amphiphilic polymer, poly(BMA-r-PEGMA-r-NAS), through π-π stacking interactions between the benzene ring tethered to the polymer and ERGO. After covalent immobilization of a primary antibody on the polymer-modified surfaces, sandwich ELISA was carried out for the detection of an antigen by use of a horseradish peroxidase (HRP)-labeled secondary antibody. Under the optimized experimental conditions, the developed electrochemical immunosensor exhibited a linear response over a wide range of antigen concentrations with a very low limit of detection (ca. 100 fg/mL, which corresponds to ca. 700 aM). The high sensitivity of the electrochemical immunosensor may be attributed not only to the enhanced electrocatalytic activity owing to ERGO but also to the minimized background current owing to the reduced nonspecific binding of proteins.
authors.affiliation: Department of Chemistry, University of Incheon, Incheon 402-776, Korea.
authors.forename: Al-Monsur Jiaul
authors.initials: AM
authors.lastname: Haque
authors.forename: Hyejin
authors.initials: H
authors.lastname: Park
authors.forename: Daekyung
authors.initials: D
authors.lastname: Sung
authors.forename: Sangyong
authors.initials: S
authors.lastname: Jon
authors.forename: Sung-Yool
authors.initials: SY
authors.lastname: Choi
authors.forename: Kyuwon
authors.initials: K
authors.lastname: Kim
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D004566:Electrodes; D004797:Enzyme-Linked Immunosorbent Assay; D006108:Graphite / Q000737:chemistry*; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D007074:Immunoglobulin G; D010087:Oxides; D017971:Tin Compounds; D006108:Graphite; C045358:stannic oxide