Label-Free Aptamer-Based Immunoglobulin Sensors Using Graphene Field-Effect Transistors

Electrical detection of specific proteins was demonstrated using aptamer-modified graphene field-effect transistors (G-FETs). Immunoglobulin E (IgE) aptamers were immobilized onto the graphene surface with 1-pyrenebutanoic acid succinimidyl ester as a linker. From an atomic-force microscopy image, the height of the graphene channel was determined to be approximately 3 nm, indicating the successful functionalization of aptamers. The slope of the transport characteristics before and after aptamer functionalization did not change, indicating that the functionalization process was carried out without introducing defects. The aptamer-modified G-FET successfully detected only the target protein while the drain current of the bare G-FETs changed by various proteins. These results suggest that the binding of the non-target protein to the graphene channel surface was sufficiently suppressed. (C) 2011 The Japan Society of Applied Physics