Hydrangea-like TiO₂/Bi₂MoO₆ porous nanoflowers triggering highly sensitive electrochemical immunosensing to tumor marker

Rapid and sensitive detection of carcinoembryonic antigen (CEA) is of great significance for cancer patients. Here, molybdenum (Mo) was doped into bismuth oxide (Bi₂O₃) by one-pot hydrothermal method forming porous tremella Bi₂MoO₆ nanocomposites with a larger specific surface area than the spherical structure. Then, a new kind of hydrangea-like TiO₂/Bi₂MoO₆ porous nanoflowers (NFs) was prepared by doping titanium into Bi₂MoO₆, where titanium dioxide (TiO₂) grew in situ on the surface of Bi₂MoO₆ nanoparticles (NPs). The hydrangea-like structure provides larger specific surface area, higher electron transfer ability and biocompatibility as well as more active sites conducive to the attachment of anti-carcinoembryonic antigen (anti-CEA) to TiO₂/Bi₂MoO₆ NFs. A novel label-free electrochemical immunosensor was then constructed for the quantitative detection of CEA using TiO₂/Bi₂MoO₆ NFs as sensing platform, showing a good linear relationship with CEA in the concentration range 1.0 pg/mL ~ 1.0 mg/mL and a detection limit of 0.125 pg/mL (S/N = 3). The results achieved with the designed immunosensor are comparable with many existing immunosensors used for the detection of CEA in real samples.