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 (Bi 2 O 3 ) by one-pot hydrothermal method forming porous tremella Bi 2 MoO 6 nanocomposites with a larger specific surface area than the spherical structure. Then, a new kind of hydrangea-like TiO 2 /Bi 2 MoO 6 porous nanoflowers (NFs) was prepared by doping titanium into Bi 2 MoO 6 , where titanium dioxide (TiO 2 ) grew in situ on the surface of Bi 2 MoO 6 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 TiO 2 /Bi 2 MoO 6 NFs. A novel label-free electrochemical immunosensor was then constructed for the quantitative detection of CEA using TiO 2 /Bi 2 MoO 6 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. Graphical abstract