Labeless Immunosensor Assay for Fluoroquinolone Antibiotics Based Upon an AC Impedance Protocol

Abstract

This paper describes the construction of a labeless immunosensor for the
\nantibiotic ciprofloxacin and its interrogation using an AC impedance protocol.
\nCommercial screen-printed carbon electrodes were used as the basis for the
\nsensor. Polyaniline was electrodeposited onto the sensors and then utilized to
\nimmobilize a biotinylated antibody for ciprofloxacin using classical avidin-
\nbiotin interactions. Electrodes containing the antibodies were exposed to
\nsolutions of antigen and interrogated using an AC impedance protocol. The
\nfaradaic component of the impedance of the electrodes was found to increase with
\nincreasing concentration of antigen. Control samples containing a non-specific
\nIgG antibody were also studied and calibration curves obtained by subtraction of
\nthe responses for specific and non-specific antibody-based sensors, thereby
\neliminating the effects of non-specific adsorption of antigen.