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Electrical Graphene Aptasensor for Ultra‐Sensitive Detection of Anthrax Toxin with Amplified Signal Transduction
Author(s) -
Kim DuckJin,
Park HaeChul,
Sohn Il Yung,
Jung JinHeak,
Yoon Ok Ja,
Park JoonShik,
Yoon MoonYoung,
Lee NaeEung
Publication year - 2013
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201203245
Subject(s) - aptamer , graphene , detection limit , biosensor , materials science , colloidal gold , nanotechnology , conjugated system , chemistry , nanoparticle , microbiology and biotechnology , chromatography , biology , polymer , composite material
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 (V g,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 V g,min shift.