Sandwich-type electrochemical immunosensing of CA125 by using nanoribbon-like Ti 3 C 2 T x MXenes and toluidine blue/UIO-66-NH 2 .

CA125 (carbohydrate antigen 125) is an important biomarker of ovarian cancer, so developing effective method for its detection is of great significance. In the present work, a novel sandwich-like electrochemical immunosensor (STEM) of CA125 was constructed by preparing nanoribbon-like Ti3 C2 Tx MXenes (Ti3 C2 Tx NR) to immobilize primary antibody (PAb) of CA125 and UIO-66-NH2 MOFs structure to immobilize second antibody (SAb) and electroactive toluidine blue (Tb) probe. In this designed STEM assay, the as-prepared Ti3 C2 Tx NR nanohybrid offers the advantages in large surface area and conductivity as carrier, and UIO-66-NH2 provided an ideal platform to accommodate SAb and a large number of Tb molecules as signal amplifier. In the presence of CA125, the peak currents of Tb from the formed STEM structure increase with the increase of CA125 level. After optimizing the related control conditions, a wide linear range (0.2-150.0 U mL-1 ) and a very low detection limit (0.05 U mL-1 ) of CA125 were achieved. It's thus expected the developed STEM strategy has important applications for the detection of CA125.