Sensitive amperometric immunosensing using polypyrrolepropylic acid films for biomolecule immobilization.
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.
Dong
Hua
H
School of Chemical and Biomedical Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798.
Li
Chang Ming
CM
Chen
Wei
W
Zhou
Qin
Q
Zeng
Zhao Xian
ZX
Luong
John H T
JH
D015374:Biosensing Techniques; D004563:Electrochemistry / Q000379:methods*; D011422:Propionates / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D012680:Sensitivity and Specificity
D011422:Propionates; D011758:Pyrroles; C518858:polypyrrolepropylic acid