Electrochemical Detection of DNA Sequences Based on Metalloporphyrins-Polypyrrole Towards a Multi-Detection Analysis

Abstract

A new polypyrrole bearing metalloporphyrins as electrochemical probes for the detection of DNA hybridization was designed. In this protocol, copolymers were synthesized from various pyrrole monomers, bearing either a metalloporphyrin as electrochemical probe or an activated ester for the immobilization of the DNA probe and they were characterized by FT-IR and SEM. Immobilization of the single strand nucleic acid probe was realized by covalent attachment to the formed copolymer, after reaction of the amino-terminated oligonucleotide with the activated ester functions. In the present work, the metalloporphyrin is a manganese porphyrin and the variations of the redox properties of the Mn2+/Mn3+ couple in the co-polypyrrole layer were analyzed after grafting of the DNA probe and hybridization reaction with the DNA target. The results showed a large variation of the electrochemical properties of the Mn2+/Mn3+ redox couple after DNA hybridization. This approach opens a new way towards the use of metalloporphyrins as electrochemical probes for DNA hybridization and towards the possibility of elaborating multidetection systems by varying the nature of the metal ion inserted into the porphyrin macrocycle.