(Invited) Electrical Detection of Biomolecules Using Graphene-Based Devices

Abstract

Label-free electrical monitoring of biorecognition events provides a promising platform, which is simpler, less expensive and requires less energy. Rapid testing of different proteins is required in various applications, including clinical diagnostics, environmental testing, food analysis, bioterrorism detection technologies, etc. Graphene, a single honeycomb-like sheet of carbon atoms, have been intensively investigated in most recent owing to its extraordinary high mobility even at room temperature [1]. Since graphene has a perfect two-dimensional structure, electrical characteristics in graphene devices are very sensitive for modulation of surface potentials in graphene channels. In this study, we have demonstrated highly sensitive electrical detection of biological molecules based on graphene devices.A monolayer graphene was obtained by mechanical cleavage of graphite or CVD-based graphene on SiO2 films. Graphene devices were fabricated by conventional lithography and lift-off method. A silicone rubber was placed on the graphene devices so that the graphene channel was immersed in a buffer solution. An Ag/AgCl reference electrode was used as the top-gated electrode to minimize environmental effects.Solution-gated graphene devices showed good transfer characteristics in buffer solution [2]. To selectively detect targets, receptors were modified on graphene channels [3-7]. For highly sensitive detection of biomolecules, small receptors such as aptamer or antigen-binding fragment (Fab) were utilized. Atomic force microscopy images revealed that receptors were successfully immobilized on the graphene channel. The receptor-modified graphene devices showed electrical detection of targets with concentration from few hundred pM to several hundred nM. Moreover, for development of highly sensitive influenza-virus sensors, glycan-modified graphene devices were also fabricated. The biological molecules were detected with high sensitivity based on graphene devices. When a different kind of receptor is functionalized on each graphene channel in the graphene-device array, many kinds of biomolecules can be electrically detected simultaneously. Therefore, the graphene-device array can be useful for the fabrication of multiplex hand-held chemical and biological sensors for home medical care. K. Novoselov, A. Geim, S. Morozov, D. Jiang, Y. Zhang, S. Dubonos, I. Grigorieva and A. Firsov, Science 306, 666 (2004). Y. Ohno, K. Maehashi, and K. Matsumoto, Biosens. Bioelectron. 26 , 1727 (2010). Y. Ohno, K. Maehashi, Y. Yamashiro, and K. Matsumoto, Nano Lett. 9, 3318 (2009). K. Maehashi, Y. Sofue, S. Okamoto, Y. Ohno, K. Inoue and K. Matsumoto, Sensors and Actuators B 187, 45 (2013). Y. Ohno, K. Maehashi, and K. Matsumoto, J. Am. Chem. Soc. 132, 18012 (2010). S. Okamoto, Y. Ohno, K. Maehashi, K. Inoue, and K. Matsumoto, Jpn. J. Appl. Phys. 51, 06FD08 (2012). N. B. M. Zaifuddin, S. Okamoto, T. Ikuta, Y. Ohno, K. Maehashi, M. Miyake, P. Greenwood, K. B. K. Teo, and K. Matsumoto, Jpn. J. Appl. Phys. 52, 06GK04 (2013).