Electrocatalytic Activity of Other Nanoparticles

Other non-metal particles have also been described as possible catalysts in electroanal3Aical systems [13, 33]. For example, copper oxide nanoparticles (CuO-NPs) of 5 nm size were mixed with 

More recently, Prussian blue nanoparticles (PB-NPs) were found to catalyze the electrochemical reduction of H2O2 when immobilized in the form of layers on ITO electrodes [14]. The application of PB-NPs as catal3Aic labels for highly sensitive detection of DNA hybridization was also reported based on their catal3Aic effect toward H2O2 when embedded in polystyrene spheres and loaded onto a gold-disk electrode [45]. 

The induced catalysis by NPs is showing special interest in the DNA biosensing technology. The application of NPs as catalysts in DNA detection systems is related to the decrease of overpotentials of the involved redox species including also the catalyzed reduction of other metallic ions used in labeling-based h34)ridization sensing. Although the most exploited materials in catalysis are the metals 

Ag-NPs are not so commonly used as Au-NPs but nevertheless their cataljAic properties in electrochemical detection have also been exploited. For instance, they were reported as promoters for electron transfer between the graphite electrode and hemoglobin in a NO sensor system where they also act as a base to attach the hemoglobin onto a pyroljAic graphite electrode while preserving the hemoglobin natural conformation and therefore its reactivity [46], With respect to the application of silver catal)Aic properties on DNA hybridization detection, the published works refer mostly to its use in combination with Au-NPs by means of chemical or electrochemical silver deposition onto them [29]. 

The catalytic properties of nanoparticles used in protein detection can also be extended to DNA analysis. For example, the selective electrocatal3Aic reduction of silver ions onto the surface of Au-NP reported by our group and applied for protein detection can be extended to DNA analysis too [47]. The hydrogen catalysis reaction induced by Au-NPs [48] and applied even for cancer cells detection [20] is expected to bring advantages for DNA detection as well. 

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