Fabrication of novel electrochemical immunosensor by mussel-inspired chemistry and surface-initiated PET-ATRP for the simultaneous detection of CEA and AFP

A functional electrochemical immunosensor was successfully designed for simultaneous and high sensitivity detection of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP). This electrochemical immunosensor was mainly designed by surface-initiated poly(glycidyl methacrylate) (PGMA) from multi-walled carbon nanotubes (MWCNTs) with the methodology of mussel-inspired chemistry (polydopamine, PDA) and metal-free photoinduced electron transfer-atom transfer radical polymerization (PET-ATRP). Controlled PGMA was initiated from MWCNTs, in which Br-functional PDA-modified MWCNTs and eosin Y (EY) were used as initiator and photocatalyst, respectively. The epoxy group of PGMA is reacted with ethylenediamine (EDA) by a ring-opening reaction, the amino and hydroxyl groups in the polymer chain provide numerous effective binding sites for carboxyl groups of signal molecules and capture antibodies, realizing highly sensitive electrochemical detection. Under optimized conditions, the obtained hybrid nanoprobes (Aq/PGMA-g-MWCNTs and Fc/PGMA-g-MWCNTs) were used as efficient electrochemical immunosensor to simultaneously detect CEA and AFP. It is worth noting that the electrochemical immunosensor performed a wide detection range and a low detection limit of CEA (163 fg/mL similar to 163 ng/mL, 56.1 fg/mL) and AFP (100 fg/mL similar to 100 ng/mL, 32.8 fg/mL), respectively. This high sensitivity and selectivity detection platform has a potential application in the simultaneous detection of more tumor markers.