Photoelectrochemical immunosensor by a Ru-bipy label on a nanostructured TiO2 electrode

A newly developed photoelectrochemistry analytical methodology was applied to selective detection of the immunoreaction between anti human IgG and human IgG. The method is based on the principle of the dye-sensitized solar cell, using an NHS-ester derivative of ruthenium polypyridine as the signal indicator and nanoparticle TiO₂ as electrode material. After performing the affinity reaction, photoelectrochemical measurement showed that anodic photocurrent was turned on and off repeatedly by control of incidental visible-light, due to light absorption of the ruthenium compound immobilized on the electrode. Owing to its separate source for excitation (light) and detection (current) and the use of electronic detection, the photoelectrochemistry system is expected as a sensitive and low cost method for the detection of biological affinity interaction.