Graphene Field Effect Transistor Biosensors Based on Aptamer for Amyloid-β Detection

The development of cost-efficient, sensitive and specific methods to detect amyloid-beta 42 (Aβ 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 Aβ 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 Aβ 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 Aβ 42, which would also enable measurements in serum-samples.