Development of a mediator-free peroxidase biosensor based on concanavalin a immobilizing horseradish peroxidase

A media-free horseradish peroxidase (HRP) biosensor has been developed. First, HRP was adsorbed by gold nanoparticles, then it was immobilized on the bare gold electrode surface by activated concanavalin A (Con A). The factors with respect to the size of the gold nanoparticles, the assembling layers, applied potential and pH influencing the performance of the biosensor were studied in detail. The optimum conditions were pH 7.0 and applied potential of -150 mV. The electrode provided a linear response to H,0, over a concentration range of 5.0 X 10(-6)similar to 1.2 x 10(-2) mol/L with a detection limit of 2.9 X 10(-6) mol/L. The system was applied to the analysis of samples, the results was satisfactory.