Fabrication of SrTiO3 Layer on Pt Electrode for Label-Free Capacitive Biosensors

• Main Authors: Francesca Malvano, Luigi Maritato, Giovanni Carapella, Pasquale Orgiani, Roberto Pilloton, Marisa Di Matteo, Donatella Albanese
• Format: Article
• Language: English
• Published: MDPI AG 2018-03-01
• Series: Biosensors
• Subjects: biosensors; label-free; perovskite; strontium titanium oxide
• Online Access: http://www.mdpi.com/2079-6374/8/1/26

Due to their interesting ferroelectric, conductive and dielectric properties, in recent years, perovskite-structured materials have begun to attract increasing interest in the biosensing field. In this study, a strontium titanate perovskite layer (SrTiO3) has been synthesized on a platinum electrode and exploited for the development of an impedimetric label-free immunosensor for Escherichia coli O157:H7 detection. The electrochemical characterization of the perovskite-modified electrode during the construction of the immunosensor, as well as after the interaction with different E. coli O157:H7 concentrations, showed a reproducible decrease of the total capacitance of the system that was used for the analytical characterization of the immunosensor. Under optimized conditions, the capacitive immunosensor showed a linear relationship from to 1 to 7 log cfu/mL with a low detection limit of 1 log cfu/mL. Moreover, the atomic force microscopy (AFM) technique underlined the increase in roughness of the SrTiO3-modified electrode surface after antibody immobilization, as well as the effective presence of cells with the typical size of E. coli.