title: Electrical graphene aptasensor for ultra-sensitive detection of anthrax toxin with amplified signal transduction.
abstract: Detection of the anthrax toxin, the protective antigen (PA), at the attomolar (aM) level is demonstrated by an electrical aptamer sensor based on a chemically derived graphene field-effect transistor (FET) platform. Higher affinity of the aptamer probes to PA in the aptamer-immobilized FET enables significant improvements in the limit of detection (LOD), dynamic range, and sensitivity compared to the antibody-immobilized FET. Transduction signal enhancement in the aptamer FET due to an increase in captured PA molecules results in a larger 30 mV/decade shift in the charge neutrality point (Vg,min ) as a sensitivity parameter, with the dynamic range of the PA concentration between 12 aM (LOD) and 120 fM. An additional signal enhancement is obtained by the secondary aptamer-conjugated gold nanoparticles (AuNPs-aptamer), which have a sandwich structure of aptamer/PA/aptamer-AuNPs, induce an increase in charge-doping in the graphene channel, resulting in a reduction of the LOD to 1.2 aM with a three-fold increase in the Vg,min shift.
authors.affiliation: Department of Chemistry, Hanyang University, Seoul 133-791, Korea.
authors.forename: Duck-Jin
authors.initials: DJ
authors.lastname: Kim
authors.forename: Hae-Chul
authors.initials: HC
authors.lastname: Park
authors.forename: Il Yung
authors.initials: IY
authors.lastname: Sohn
authors.forename: Jin-Heak
authors.initials: JH
authors.lastname: Jung
authors.forename: Ok Ja
authors.initials: OJ
authors.lastname: Yoon
authors.forename: Joon-Shik
authors.initials: JS
authors.lastname: Park
authors.forename: Moon-Young
authors.initials: MY
authors.lastname: Yoon
authors.forename: Nae-Eung
authors.initials: NE
authors.lastname: Lee
keywords: anthrax toxin; aptamers; biosensors; field-effect transistors; graphene