An ultrasensitive fluorescent aptasensor for detection of cancer marker proteins based on graphene oxide-ssDNA

A novel biosensing platform was developed by integrating a new ssDNA aptamer and graphene oxide (GO) for highly sensitive and selective detection of liver cancer biomarkers (alpha-fetoprotein, AFP). The key concept of this biosensing platform is that the fluorescence of dye-modified ssDNA can be effectively quenched by GO after forming the hybrid structure of graphene oxide-ssDNA (GO-ssDNA). The AFP can selectively react with GO-ssDNA and lead to the decomposition of GO-ssDNA, which results in the recovery of fluorescence, and an increase in fluorescence intensity with the increasing concentration of AFP in the range of 0 to 300 pg mL^-1. The linear range was obtained from 1 to 150 pg mL^-1 and the detection limit was 0.909 pg mL^-1. Moreover, this biosensing platform can be applied to serum and cell imaging for the detection of AFP. The results show that the proposed biosensor has great potential application in AFP-related clinical diagnosis and research.