A new conductometric biosensor based on horseradish peroxidase immobilized on chitosan and chitosan/gold nanoparticle films

Abstract A new conductometric biosensor was developed and characterized; the biosensor was based on horseradish peroxidase that was deposited in chitosan and chitosan/AuNPs films. The biosensors were characterized by scanning electron microscopy and current-voltage curves. Current-voltage curves in biosensors showed that the electrical conductivity and bistability in biosensors can be modulated by horseradish peroxidase. Horseradish peroxidase catalyzed the reduction of H2 O2 to H2 O with the oxidation of the prosthetic group (Fe3+) in the enzyme to Fe4+=O. Conductometric signal in the biosensors increased with the gradual increase of H2 O2 concentration, and it was due to the H2 O2 reduction. Linear hydrogen peroxide detection was observed for a concentration between 0 and 15 mm. The results proved that these biosensors could have promising industrial applications, due to its rapid and sensitive H2 O2 detection.