CdS/Au/TiO₂ nanowire composite as selective, sensitive and reliable immunosensors for detecting octachlorostyrene under visible light

We report on the synthesis of the CdS/Au/TiO2 nanowire photoelectrode (CdS/Au/TiO2 NWs) using the elec-trodeposition and pulse-electrical deposition methods. The characteristics of CdS/Au/TiO2 nanowires were investigated by scanning electron microscopy, transmission electron microscopy, and energy dispersive spec-troscopy. By fixing cross-linking anti-octachlorostyrene antibody onto the CdS/Au/TiO2 nanowire, the photo-electrochemical (PEC) immunosensor was fabricated for detecting octachlorostyrene (OCS) under visible light. This PEC sensor shows high stability, good sensitivity and selectivity for OCS of concentration from 10(-12) M to 5 x 10(-5 )M with a limit of detection (LOD) of 2.24 x 10(-12) M. The photocurrent response of device showed the linear dependence on logarithm of OCS concentration with a regression equation of (Io-I)/Io = 0.78665 + 0.06111 log COCS (where R-2 = 0.992) in the concentration range from 10(-12 )M to 10(-7) M. As a result, we suggest that the nanowire composite materials could be effectively used for fabricating PEC immunosensors to detect OCS in the water sample.