Comparison by QCM and photometric enzymatic test of the biotin-avidin recognition on a biotinylated polypyrrole

摘要

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 assembly thank to the biotin/avidin interaction betwen avidine and B-GOx. Indeed the estimated amount from the QCM measurement corresponds to the specific recognition fo avidin/B-GOx added to 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 na avidin layer linked bya dsorption to a polypyrrole free from biotin units. From QCM meaurements 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 vaules have been corroborated by measurements of the enzymatic activity of GOx.