Département de chimie moléculaire

The authors demonstrate herein a newly developed photoelectrochem. immunosensor for the detn. of anti-cholera toxin antibody by using a photosensitive biotinylated polypyrrole film. The latter was generated by electro-oxidn. of a biotinylated tris(bipyridyl) ruthenium(II) complex bearing pyrrole groups. The photoexcitation of this modified electrode potentiostated at 0.5 V vs SCE, in the presence of an oxidative quencher, pentaaminechloro cobalt(III) chloride (15 mM), led to a cathodic photocurrent. As a result of the affinity interactions, a layer of biotinylated cholera toxin was firmly bound to the functionalized polypyrrole film via avidin bridges. The resulting modified electrodes were tested as immunosensors for the detection of the corresponding antibody from 0 to 200 $μ$g mL-1. The antibody concn. was measured through the decrease in photocurrent intensity resulting from its specific binding onto the polymeric coating, the detection limit being 0.5 $μ$g mL-1. [on SciFinder(R)]