Epitaxial graphene immunosensor for human chorionic gonadotropin

Detection of binding of hCG with its graphene-bound antibody was monitored by measuring reduction of the channel current of the graphene biosensor. The sensitivity of the sensor device was investigated using varying concentrations of hCG, with changes in the channel resistance of the sensor observed upon exposure to hCG. The detection limit of the sensor was 0.62 ng/mL and the sensor showed a linear response to hCG in the range 0.62-5.62 ng/mL with a response of 142 Ω/ng/mL. At concentrations above 5.62 ng/mL the sensor begins to saturate.