title: Sensitive amperometric immunosensing using polypyrrolepropylic acid films for biomolecule immobilization.
abstract: An electrochemical immunosensor was constructed using an electropolymerized pyrrolepropylic acid (PPA) film with high porosity and hydrophilicity. A high density of carboxyl groups of PPA was used to covalently attach protein probes, leading to significantly improved detection sensitivity compared with conventional entrapment methods. As a model, anti-mouse IgG was covalently immobilized or entrapped in the PPA film and used in a sandwich-type alkaline phosphatase-catalyzing amperometric immunoassay with p-aminophenyl phosphate as the substrate. With covalent binding, the detection limit for IgG in PBS buffer, pH 7.4, was 100 pg/mL with a dynamic range of 5 orders of magnitude. The covalent bonding mode in the carbonate-bicarbonate buffer, pH 9.6, further brought down the detection limit to 20 pg/mL with remarkable selectivity.
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798.
authors.forename: Hua
authors.initials: H
authors.lastname: Dong
authors.forename: Chang Ming
authors.initials: CM
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhou
authors.forename: Zhao Xian
authors.initials: ZX
authors.lastname: Zeng
authors.forename: John H T
authors.initials: JH
authors.lastname: Luong
mesh_terms: D015374:Biosensing Techniques; D004563:Electrochemistry / Q000379:methods*; D011422:Propionates / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D012680:Sensitivity and Specificity
chemical_list: D011422:Propionates; D011758:Pyrroles; C518858:polypyrrolepropylic acid