title: Electrogenerated trisbipyridyl Ru(II)-/nitrilotriacetic-polypyrene copolymer for the easy fabrication of label-free photoelectrochemical immunosensor and aptasensor: application to the determination of thrombin and anti-cholera toxin antibody.
abstract: A bifunctional copolymer was electrogenerated, which allows efficient bioreceptor immobilization and transduction of the biorecognition event. This copolymer was formed using pyrenebutyric acid Nα',Nα-bis(carboxymethyl)-L-lysine amide (NTA-pyrene) and [tris-(2,2'-bipyridine) (4,4'-bis(4-pyrenyl-1-ylbutyloxy)-2,2'-bipyridine] ruthenium(II) hexafluorophosphate (Ru(II)-pyrene) complex. The pyrene groups, present in both compounds, undergo oxidative electropolymerization on platinum electrodes. The resulting copolymer contains NTA moieties, which were used as a versatile immobilization system for biotin- and histidine-tagged biomolecules, while Ru(II)-pyrene was employed as a photoelectrochemical transducing molecule. The efficiency of this copolymer for biomolecule anchoring was investigated with biotin- and histidine- tagged glucose oxidases, biotin-tagged cholera toxin and a histidine-tagged thrombin aptamer. The constructed enzyme electrodes exhibited an amperometric response toward glucose at 0.6 V vs SCE, demonstrating the anchoring of this enzyme via two coordination systems. An immunosensor configuration based on the immobilization of biotin-tagged cholera toxin was applied to the detection of anti-cholera antibody while the aptasensor based on the immobilization of histidine-tagged thrombin aptamer was tested for thrombin determination. The biorecognition events were monitored via the evolution of the photocurrent intensity generated by the polymerized Ru(II)-pyrene in the presence of visible light and a sacrificial donor (ascorbate). The binding of the targets hinders the diffusion of the sacrificial donor, inducing thus a photocurrent decrease. The constructed immunosensor presents a specific label-free photoelectrochemical response to anti-cholera antibody without labeling step, the detection limit being 0.2 μg mL⁻¹. The label-free photoelectrochemical response of the aptasensor varies linearly with thrombin concentrations up to 10 pmol L⁻¹, the detection limit being 1×10⁻¹³ mol L⁻¹.
authors.affiliation: Département de Chimie Moléculaire, Université Joseph Fourier, UMR-5250, ICMG FR-2607, CNRS, Grenoble, France.
authors.forename: Yao
authors.initials: Y
authors.lastname: Wenjuan
authors.forename: Alan
authors.initials: A
authors.lastname: Le Goff
authors.forename: Nicolas
authors.initials: N
authors.lastname: Spinelli
authors.forename: Michael
authors.initials: M
authors.lastname: Holzinger
authors.forename: Guo-Wang
authors.initials: GW
authors.lastname: Diao
authors.forename: Dan
authors.initials: D
authors.lastname: Shan
authors.forename: Eric
authors.initials: E
authors.lastname: Defrancq
authors.forename: Serge
authors.initials: S
authors.lastname: Cosnier
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000737:chemistry; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D002772:Cholera Toxin / Q000276:immunology / Q000302:isolation & purification*; D055664:Electrochemical Techniques; D006801:Humans; D008239:Lysine / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011721:Pyrenes / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry; D013917:Thrombin / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D052157:Aptamers, Nucleotide; D011108:Polymers; D011721:Pyrenes; C081676:thrombin aptamer; D012428:Ruthenium; D002772:Cholera Toxin; D013917:Thrombin; D008239:Lysine