An ultrasensitive electrochemiluminescence immunosensor for alpha-fetoprotein based on a poly(aniline-luminol)/graphene oxide nanocomposite

An ultrasensitive electrochemiluminescence (ECL) immunosensor for alpha-fetoprotein (AFP) detection based on a poly(aniline-luminol)/graphene oxide nanocomposite was developed. The nanocomposite, which was prepared using a fast and simple chemical oxidation strategy for the first time, showed excellent ECL performance. This outstanding ECL performance is due to the formation of poly(aniline-luminol) on the graphene oxide (GO) surface and the excellent electron-transfer properties of GO. Moreover, the poly(aniline-luminol)/graphene oxide nanocomposite has abundant amino groups at its surface, making it a good platform for biomacromolecule labeling. Using the nanocomposite, a novel ECL immunosensor for the determination of AFP was successfully developed. Anti-AFP was immobilized on the surface of a poly(aniline-luminol)/graphene oxide nanocomposite-modified electrode using a glutaraldehyde crosslinking method to form the ECL immunosensor. The AFP was then captured at the modified electrode surface through an antigen–antibody immunoreaction. When the AFP was captured by its antibody, the ECL intensity decreased. This ECL immunosensor for the detection of AFP exhibited a linear range of 1.7 × 10 −12 to 1.7 × 10 −8  mg mL −1 and a detection limit of 5 × 10 −13  mg mL −1 , indicating high sensitivity and linearity across a wide concentration range. Furthermore, the immunosensor was successfully applied to determine AFP in a real-world human serum sample. A new poly(aniline-luminol)/graphene oxide nanocomposite was prepared using a fast and simple strategy for the first time, and an ultrasensitive electrochemiluminescence (ECL) immunosensor for alpha-fetoprotein (AFP) detection based on this nanocomposite was developed