title: A water-dispersible, ferrocene-tagged peptide nanowire for amplified electrochemical immunosensing.
abstract: A ferrocence (Fc)-tagged peptide comprising the phenylalanine-phenylalanine (Phe-Phe) sequence was synthesized and allowed to self-assemble into uniform nanowires with a diameter of ca. 100 nm and lengths in the range of 5-10 µm. The Fc-tagged peptide nanowire (Fc-PNW) become well dispersed in aqueous solution when coated with poly(diallyldimethylammonium chloride) (PDDA). Gold nanoparticles (AuNPs) and antibody molecules can then be adsorbed onto the Fc-PNW surface. The resultant antibody modified Fc-PNW was explored as a detection probe for sensitive electrochemical immunosensing in a sandwich assay wherein the capture antibody was attached onto a graphene/gold nanoparticle (AuNPs-GN) composite film. The as prepared electrochemical immunosensor possesses a low detection limit (5 fg/mL) for human IgG and a wide linear range encompassing four orders of magnitude (from 10 fg/mL to 100 pg/mL). Such a low detection limit stems from the significant signal amplification by the large number of Fc moieties on the PNW (for a 5-µm-long Fc-PNW, the number of Fc moieties is 5×10⁵). The electrochemical immunosensor is also highly selective and the sensor was demonstrated to be amenable to real sample analysis.
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Ding
authors.forename: Ding
authors.initials: D
authors.lastname: Li
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Kai
authors.initials: K
authors.lastname: Zhao
authors.forename: Wei
authors.initials: W
authors.lastname: Du
authors.forename: Jinyun
authors.initials: J
authors.lastname: Zheng
authors.forename: Minghui
authors.initials: M
authors.lastname: Yang
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods; D004151:Dipeptides / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D000075163:Metallocenes; D053770:Nanowires / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D055910:Antibodies, Immobilized; D004151:Dipeptides; D005296:Ferrous Compounds; D007074:Immunoglobulin G; D000075163:Metallocenes; D014867:Water; C026650:phenylalanylphenylalanine; D006046:Gold; C004998:ferrocene