Copper hexacyanoferrate nanoparticles modified electrodes: A versatile tool for biosensors

ANA PAULA BAIONI; MARCIO VIDOTTI; PABLO A. FIORITO; SUSANA I. CÓRDOBA DE TORRESI

JOURNAL OF ELECTROANALYTICAL CHEMISTRY - (Print)

ELSEVIER SCIENCE SA

Año: 2008 vol. 622 p. 219 - 224

1572-6657

Copper hexacyanoferrate nanoparticles of about 30 nm in size have been prepared by the sonochemical irradiation of a mixture of aqueous potassium ferricyanide and copper chloride solutions. The nanoparticles were immobilized onto fluorine doped tin oxide (FTO) electrodes by using the electrostatic deposition layer-by-layer technique (LbL), obtaining electroactive films with electrocatalytic properties towards H2O2 reduction, providing higher currents than those observed for electrodeposited bulk material, even in electrolytes containing View the MathML source, Na+ and K+. The nanoparticles assembly was used as mediator in a glucose biosensor by immobilizing glucose oxidase enzyme by both, cross-linking and LbL techniques. Sensitivities obtained were dependent on the immobilization method ranging from 1.23 μA mmol−1 L cm−2 for crosslinking to 0.47 μA mmol−1 L cm−2 for LbL; these values being of the same order than those obtained with electrodes where the amount of enzyme used is much higher. Moreover, the linear concentration range where the biosensors can operate was 10 times higher for electrodes prepared with the LbL immobilization method than with the conventional crosslinking one.