Optimization of a nanostructured surface for the development of electrochemical immunosensors

RIBERI, WALTER IVÁN; ZON, MARÍA ALICIA; FERNÁNDEZ, HÉCTOR; ARÉVALO, FERNANDO JAVIER

JOURNAL OF ELECTROANALYTICAL CHEMISTRY - (Print)

ELSEVIER SCIENCE SA

Año: 2019 vol. 836 p. 38 - 44

1572-6657

It is known that in the development of electrochemical immunosensors, the electrode is used both for the im-mobilization of antibodies and for carrying out the redox reaction. Therefore, it is important to have an electricalconductive surface with the possibility of retaining the antibodies. To achieve a better sensitivity and a greaterwork concentration range, the surface of the electrode can be modified with different appropriate materials suchas multi-walled carbon nanotubes (MWCNT) and gold nanoparticles (AuNPs) among others. In this work, thedesign of a platform for an electrochemical immunosensor was studied. Thus, the optimization of screen printedcarbon electrodes modified with a dispersion of MWCNT in polyethylenimine (MWCNT/PEI) and AuNPs wasperformed, through a multivariate optimization and experimental design. A factorial design of 32levels wasused, where the variables were the volumes of AuNPs solution and MWCNT/PEI dispersion for given con-centrations, respectively. The optimized responses were the cathodic peak current for the reduction of K3[Fe(CN)6] and the charge transfer resistance for the K4[Fe(CN)6]/K3[Fe(CN)6] redox couple, using cyclic voltam-metry and electrochemical impedance spectroscopy. The cathodic peak current was fitted using a lineal model,while the charge transfer resistance was fitted by a quadratic model. The desirability function was used todetermine the surface with a lower resistance to charge transfer and a higher current for the reduction of K3[Fe(CN)6]. Therefore, the optimized nanostructured surface promises to be a suitable structure for the developmentof a new electrochemical immunosensor.