RESUMO
The electrochemiluminescence (ECL) of a luminol derivate (ABEI) generated both by a carbon electrode and a polypyrrole-coated carbon electrode was examined. It was found that the polypyrrole film (ppy) did not inhibit the ECL. After that, ABEI anchored on a single stranded DNA target (ODNt) has been used for the ECL detection of the hybridization between a complementary single stranded DNA probe (ODNp) covalently linked to a polypyrrole support and the ODNt. The ECL detection has been performed using a DNA sensor having a low surface concentration of ODNp probes, constituted of a polypyrrole copolymer electrosynthesized from a pyrrole-ODNp/pyrrole monomer ratio of 1/20,000.
Assuntos
Luminol/análogos & derivados , Hibridização de Ácido Nucleico/métodos , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Eletroquímica/métodos , Eletrodos , Medições Luminescentes/métodos , Luminol/química , Membranas Artificiais , Polímeros , PirróisRESUMO
By gravimetric measurements using a quartz cristal microbalance (QCM), we have studied the immobilization of biotinylated glucose oxidase enzymes (B-GOx) bound through on an intermediate avidin layer to a biotinylated polypyrrole film. The aim is to assess the amount of B-GOx specifically anchored on the biotinylated polypyrrole/avidin assembly thank to the biotin/avidin interaction between avidin and B-GOx. Indeed the estimated amount from the QCM measurement corresponds to the specific recognition of avidin/B-GOx added to a non-specific recognition (adsorption) of B-GOx. In order to discriminate these two phenomena, we have carried out a study by QCM of the anchoring of B-GOx on an avidin layer linked by adsorption to a polypyrrole free from biotin units. From QCM measurements we have deduced for the biotinylated polypyrrole/avidin assembly that the amount of B-GOx bound via the biotin/avidin interaction and those due to the avidin adsorption process correspond to 3.9 pmol cm(-2) (1.3 equivalent of B-Gox monolayer) and 1.4 pmol cm(-2) (0.46 equivalent of B-GOx monolayer) respectively. These values have been corroborated by measurements of the enzymatic activity of GOx.
