Photoelectrochemical immunoassay based on chemiluminescence as internal excited light source

The hybrids, N -aminobutyl- N -ethylisoluminol (ABEI), horseradish peroxidase (HRP) and cancer antigen 125   s antibody (Ab2) immobilized graphene oxide (GO), were prepared, which exhibited excellent chemiluminescence (CL) activity. The zinc oxide nanorods (ZNRs) grew on reduced graphene oxide (RGO) modified paper working electrode (ZNRs-RGO/PWE) via an in situ growth method. The deposition of CdS quantum dots (QDs) on ZNRs/RGO-PWE resulted in an enhanced excitation and photo-to-electric conversion efficiency. The ABEI-GO@HRP/Ab2CL system was employed as an internal excited light source. A photoelectrochemical (PEC) immunosensor based on CdS-sensitized ZNRs anchored RGO as the photoactive matrix and ABEI-GO@HRP/Ab2 as the CL labels was established for sensitive detection of cancer antigen 125 (CA 125). As a model, sandwich CA 125-antibody was taken as molecular reorganization elements on this sensor for the sensitive determination of CA 125 in the linear range from 5.0   ×   10 −4   U/mL to 500   U/mL with a detection limit of 2.0   ×   10 −4   U/mL. The specificity, reproducibility, and stability of this sensor were also investigated. This proposed method might be attractive for clinical and biomedical applications.