▎ 摘　　要

The development of cost-efficient, sensitive and specificmethods to detectamyloid-beta 42 (A beta 42) biomarkers in cerebrospinal fluid and serum-samples is of considerable interest to enable early and reliable diagnosis of Alzheimer's disease as a precondition for future disease-modifying therapies. This paper presents a reduced graphene oxide field effect transistor (r-GO FET) for label free ultrasensitive detection of an A beta 42-biomarker with RNA aptamer. The channel in the device was formed by reduction of graphene oxide nanosheets by self-assembly process. As a result, the interaction between A beta 42 and RNA aptamer on the surface of r-GO channel caused a linear response in the shift of the gate voltage (V-TG) where the minimum conductivity occurs. The r-GO FET can detect the biomarker in range of 1ng/ml to 1pg/ml at pH 7.4 with high specificity. The developed r-GO FET is a low-cost, highly sensitive and selective method for detecting tiny concentrations of A beta 42, which would also enable measurements in serum-samples.