We report on the development of an enzyme-amplified sandwich-type immunosensor based on a thin gold film sputtered on an anodic nanoporous niobium oxide (Au@Nb(2)O(5)) electrode. The electrocatalytic activity of enzymatically amplified electroactive species and a stable electrode consisting of Au@Nb(2)O(5) were used to obtain a powerful signal amplification of the electrochemical immunobiosenso...

An interference-free amperometric biosensor for the quantitative xanthine analysis is described. Xanthine was monitored through the electrochemical reduction of hydrogen peroxide (produced upon its enzyme-catalyzed oxidation) at a constant applied potential of -50 mV (vs. Ag/AgCl). The biosensor was designed on the basis of a graphite electrode modified with microquantities of platinum and pall...

An ultrasensitive DNA biosensor has been developed through in-situ labeling of electroactive melamine-Cu(2+) complex (Mel-Cu(2+)) on the end of hairpin-like probe using gold nanoparticles (AuNPs) as the signal amplification platform. The 3'-thiolated hairpin-like probe was first immobilized to the gold electrode surface by the Au-S bond. The AuNPs were then tethered on the free 5'-end of the im...

Quercetin interaction with dsDNA was investigated electrochemically using two types of DNA biosensor in order to evaluate the occurrence of DNA damage caused by oxidized quercetin. The results showed that quercetin binds to dsDNA where it can undergo oxidation. The radicals formed during quercetin oxidation cause breaks of the hydrogen bonds in the dsDNA finally giving rise to 8-oxoguanine sinc...

Electrochemical biosensors are widely recognized in biosensing devices due to the fact that gives a direct, reliable, and reproducible measurement within a short period. During bio-interaction process and the generation of electrons, it produces electrochemical signals which can be measured using an electrochemical detector. A formaldehyde biosensor was successfully developed by depositing an i...

A proximity-dependent surface hybridization strategy is employed for designing a "signal-on" electrochemical DNAzyme biosensor. By taking advantage of the high sensitivity of the PDSH strategy, and by realizing the enzymatic hydrolysis reaction in a homogenous system with a unimolecular design, the proposed biosensor shows a very high sensitivity to target molecules.