Cyclic voltammetric responses of horseradish peroxidase multilayers on electrodes.

The catalytic responses obtained with step-by-step neutravidin-biotin deposition of successive monolayers of HRP are analyzed by means of cyclic voltammetry. The theoretical tools that have been developed allowed full characterization of the multilayered HRP coatings by means of a combination between closed-form analysis of limiting behaviors and finite difference numerical computations. An analysis of the experiments in which the number of monolayers was extended to 16 allowed an approximate determination of the average thickness of each monolayer, pointing to a compact arrangement of neutravidin and biotinylated HRP. The piling up of so many monolayers on the electrode allowed an improvement of the catalytic current by a factor of ca. 10, leading to very good sensitivities in term of cosubstrate detection.