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. Graphical abstract 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.