Edge promoted ultrasensitive electrochemical detection of organic bio-molecules on epitaxial graphene nanowalls.

Pradip Kumar Roy, Abhijit Ganguly, Wei-Hsun Yang, Chien-Ting Wu, Jih-Shang Hwang, Yian Tai, Kuei-Hsien Chen, Li-Chyong Chen, Surojit Chattopadhyay

Journal: Biosensors & bioelectronics 2016;70():137-44

PMID: 25801954

Full Text on Elsevier Science View on PubMed

Abstract

We report the simultaneous electrochemical detection of dopamine (DA), uric acid (UA) and ascorbic acid (AA) on three dimensional (3D) unmodified 'as-grown' epitaxial graphene nanowall arrays (EGNWs). The 3D few layer EGNWs, unlike the 2D planar graphene, offers an abundance of vertically oriented nano-graphitic-edges that exhibit fast electron-transfer kinetics and high electroactive surface area to geometrical area (EAA/GA≈134%), as evident from the Fe(CN)6(3-/4-) redox kinetic study. The hexagonal sp(2)-C domains, on the basal plane of the EGNWs, facilitate efficient adsorption via spontaneous π-π interaction with the aromatic rings in DA and UA. Such affinity together with the fast electron kinetics enables simultaneous and unambiguous identification of individual AA, DA and UA from their mixture. The unique edge dominant EGNWs result in an unprecedented low limit of detection (experimental) of 0.033 nM and highest sensitivity of 476.2 µA/µM/cm(2), for UA, which are orders of magnitude higher than comparable existing reports. A reaction kinetics based modeling of the edge-oriented 3D EGNW system is proposed to illustrate the superior electro-activity for bio-sensing applications.

Address: Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan.; Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan; Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan.; Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.; Nano Device Materials Characterization Division, National Nano Device Laboratories, Hsinchu, Taiwan.; Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung, Taiwan.; Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan; Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan. Electronic address: [email protected].; Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan. Electronic address: [email protected].; Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan; Biophotonics and Molecular Imaging Research Centre, National Yang Ming University, Taipei, Taiwan. Electronic address: [email protected].

DOI: 10.1016/j.bios.2015.03.027

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MeSH Terms: Biopolymers, Complex Mixtures, Conductometry, Equipment Design, Equipment Failure Analysis, Graphite, Immunoassay, Microchemistry, Nanoparticles, Organic Chemicals, Reproducibility of Results, Sensitivity and Specificity