title: Graphene-based nanoprobes and a prototype optical biosensing platform.
abstract: Biochemical and biomedical applications of graphene are critically dependent on the interaction between biomolecules and the nanomaterial. In this work, we developed a graphene-based signal-amplification nanoprobe by combining anti-immunoglobulin G (anti-IgG) and horseradish peroxidase (HRP) with graphene oxide (GO). The structure and function of HRP in the nano-interface of GO were firstly investigated, which demonstrated that the enzyme retained 78% of its native activity and 77% of its native α-helix content. HRP and anti-IgG were then co-adsorbed onto GO to form bifunctional nanoprobes. The nanoprobes provide both improved binding ability and signal-amplification ability. Comparing with conventional bioconjugates such as enzyme-linked antibody, co-adsorption could avoid chemical conjugation between biomolecules, keeping their bioactivity well. As an example for their application, the nanoprobes were used to obtain amplified signals in a sandwich-type immunoassay for cancer marker, instead of conventional colorimetric conjugates. This approach provided a detection limit of 10 pg/mL alpha-fetoprotein (AFP), which was much more sensitive than conventional enzyme-linked immunosorbent assay (ELISA) methods. The easily fabricated GO-based nanoprobes have the potential to become universal probes for molecular diagnostics.
authors.affiliation: School of Chemistry and Materials Science, Ludong University, Yantai 264025, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.forename: Dongfang
authors.initials: D
authors.lastname: Wang
authors.forename: Shijiang
authors.initials: S
authors.lastname: He
authors.forename: Jiang
authors.initials: J
authors.lastname: Li
authors.forename: Bianying
authors.initials: B
authors.lastname: Feng
authors.forename: Peijun
authors.initials: P
authors.lastname: Ma
authors.forename: Pingping
authors.initials: P
authors.lastname: Xu
authors.forename: Shanmin
authors.initials: S
authors.lastname: Gao
authors.forename: Shengxiao
authors.initials: S
authors.lastname: Zhang
authors.forename: Quanwen
authors.initials: Q
authors.lastname: Liu
authors.forename: Jianxin
authors.initials: J
authors.lastname: Lu
authors.forename: Shiping
authors.initials: S
authors.lastname: Song
authors.forename: Chunhai
authors.initials: C
authors.lastname: Fan
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D004800:Enzymes, Immobilized / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007074:Immunoglobulin G / Q000276:immunology; D057230:Limit of Detection; D049329:Nanostructures / Q000737:chemistry; D009369:Neoplasms / Q000175:diagnosis; D010087:Oxides / Q000737:chemistry; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D055910:Antibodies, Immobilized; D004800:Enzymes, Immobilized; D007074:Immunoglobulin G; D010087:Oxides; D000509:alpha-Fetoproteins; D006108:Graphite; D006735:Horseradish Peroxidase
keywords: Cancer marker; Graphene oxide (GO); Immunoassay; Nanoprobe; Signal amplification