Comparison by QCM and photometric enzymatic test of the biotin-avidin recognition on a biotinylated polypyrrole.
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.
Dupont-Filliard
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A
Laboratoire d'Electrochimie Moléculaire et Structures des Interfaces UMR 5819 (CNRS-CEA-Université J. Fourier), Département de Recherche Fondamentale sur la Matière Condensée/CEA-Grenoble, 17, avenue des Martyrs, 38054 Grenoble Cedex 9, France.
Billon
M
M
Guillerez
S
S
Bidan
G
G