title: Graphene-based liquid-gated field effect transistor for biosensing: Theory and experiments.
abstract: We present an experimental and theoretical characterization for reduced Graphene-Oxide (rGO) based FETs used for biosensing applications. The presented approach shows a complete result analysis and theoretically predictable electrical properties. The formulation was tested for the analysis of the device performance in the liquid gate mode of operation with variation of the ionic strength and pH-values of the electrolytes in contact with the FET. The dependence on the Debye length was confirmed experimentally and theoretically, utilizing the Debye length as a working parameter and thus defining the limits of applicability for the presented rGO-FETs. Furthermore, the FETs were tested for the sensing of biomolecules (bovine serum albumin (BSA) as reference) binding to gate-immobilized anti-BSA antibodies and analyzed using the Langmuir binding theory for the description of the equilibrium surface coverage as a function of the bulk (analyte) concentration. The obtained binding coefficients for BSA are found to be same as in results from literature, hence confirming the applicability of the devices. The FETs used in the experiments were fabricated using wet-chemically synthesized graphene, displaying high electron and hole mobility (µ) and provide the strong sensitivity also for low potential changes (by change of pH, ion concentration, or molecule adsorption). The binding coefficient for BSA-anti-BSA interaction shows a behavior corresponding to the Langmuir adsorption theory with a Limit of Detection (LOD) in the picomolar concentration range. The presented approach shows high reproducibility and sensitivity and a good agreement of the experimental results with the calculated data.
authors: Center for Electrochemical Surface Technology (CEST), Viktor-Kaplan Strasse 2, 2700 Wiener Neustadt, Austria. Electronic address: Rozman.Ciril.fl@ait.ac.at.
authors: Ciril
authors: C
authors: Reiner-Rozman
authors: AIT Austrian Institute of Technology, Donau City Strasse 1, 1220 Vienna, Austria. Electronic address: Melanie.Larisika@ait.ac.at.
authors: Melanie
authors: M
authors: Larisika
authors: AIT Austrian Institute of Technology, Donau City Strasse 1, 1220 Vienna, Austria; Center for Electrochemical Surface Technology (CEST), Viktor-Kaplan Strasse 2, 2700 Wiener Neustadt, Austria. Electronic address: C.Nowak@ait.ac.at.
authors: Christoph
authors: C
authors: Nowak
authors: AIT Austrian Institute of Technology, Donau City Strasse 1, 1220 Vienna, Austria. Electronic address: Wolfgang.Knoll@ait.ac.at.
authors: Wolfgang
authors: W
authors: Knoll
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003198:Computer Simulation; D003217:Conductometry / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D056656:Lab-On-A-Chip Devices; D008956:Models, Chemical; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000032:analysis / Q000737:chemistry*; D014173:Transistors, Electronic
chemical_list: D012710:Serum Albumin, Bovine; D006108:Graphite
keywords: Biosensing; FET; Liquid-gate; Solid–liquid-interface; Theoretical simulation; rGO graphene