Département de chimie moléculaire

This paper describes the construction of an impedimetric immunosensor for the label-free detection of ciprofloxacin, an antibiotic belonging to synthetic fluoroquinolones. A poly(pyrrole-N-hydroxysuccinimide) film was electrogenerated onto electrodes and then used for the reagentless covalent binding of a fluoroquinolone model bearing an amino group. The resulting electrodes were utilized to immobilize a layer of anticiprofloxacin antibody onto the polymer surface by immunoreaction. In presence of ciprofloxacin, the antibody was displaced in soln. inducing marked changes in the impedance of the sensor electrodes. These phenomena were detected and characterized by electrochem. impedance spectroscopy allowing the selective detection of extremely low ciprofloxacin concn., namely, 1 × 10-12 g mL-1 or 3 pmol L-1. Sensors exposed to ciprofloxacin showed a decrease in the sum of the interfacial resistances with the increase in ciprofloxacin concn. from 1 × 10-12 to 1 × 10-6 g mL-1. [on SciFinder(R)]