Screen Printed Based Impedimetric Immunosensor for Rapid Detection of Escherichia coli in Drinking Water

Sensors

卷:20

Sergio Bolletti Censi¹  Marina Papaianni²  Rosanna Capparelli²  Rosa Gaglione³  Angela Arciello³  Raffaele Velotta⁴  Martina Cimafonte⁴  Bartolomeo Della Ventura⁵  Giorgia Borriello⁶  Andrea Fulgione⁶ 

[1] Cosvitech Società Consortile a Responsabilità Limitata, 80142 Naples, Italy;

[2] Department of Agriculture, University of Naples “Federico II”, Via Università, 133, 80055 Portici Naples, Italy;

[3] Department of Chemical Sciences, University of Naples “Federico II”, Via Cinthia, 26, 80126 Naples, Italy;

[4] Department of Physics “Ettore Pancini”, University of Naples “Federico II”, Via Cinthia, 26, 80126 Naples, Italy;

[5] Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy;

[6] Istituto Zooprofilattico Sperimentale del Mezzogiorno, Via Salute, 2, 80055 Portici Naples, Italy;

关键词: escherichia coli;    immunosensor;    electrochemical impedance spectroscopy;    antibodies;    photochemical immobilization technique;    cyclic voltammetry;   

DOI  :  10.3390/s20010274

来源: DOAJ

【 摘 要 】

The development of a simple and low cost electrochemical impedance immunosensor based on screen printed gold electrode for rapid detection of Escherichia coli in water is reported. The immunosensor is fabricated by immobilizing anti-E. coli antibodies onto a gold surface in a covalent way by the photochemical immobilization technique, a simple procedure able to bind antibodies upright onto gold surfaces. Impedance spectra are recorded in 0.01 M phosphate buffer solution (PBS) containing 10 mM Fe(CN)₆³⁻/Fe(CN)₆⁴⁻ as redox probe. The Nyquist plots can be modelled with a modified Randles circuit, identifying the charge transfer resistance R_ct as the relevant parameter after the immobilization of antibodies, the blocking with BSA and the binding of E. coli. The introduction of a standard amplification procedure leads to a significant enhancement of the impedance increase, which allows one to measure E. coli in drinking water with a limit of detection of 3 × 10¹ CFU mL⁻¹ while preserving the rapidity of the method that requires only 1 h to provide a “yes/no” response. Additionally, by applying the Langmuir adsorption model, we are able to describe the change of R_ct in terms of the “effective” electrode, which is modified by the detection of the analyte whose microscopic conducting properties can be quantified.

【 授权许可】

Unknown