BioChip J. (2014) 8(2): 129-136 DOI 10.1007/s13206-014-8208-x Abstract We report the development of a novel non- enzymatic glucose sensor based on single-walled car- bon nanotube film electrodes coated with iridium nano- particles (IrNPs-SWCNT). The SWCNT film electrode was first loaded with iridium nanoparticles (IrNPs) by an easily controllable chronocoulometry technique. The SWCNT film electrode coated with IrNPs was characterized by field emission scanning electron mi- croscopy and electrochemical techniques like cyclic voltammetry (CV) and amperometry. There was no cur- rent response for glucose oxidation in neutral and aci- dic media, but a couple of oxidative and reductive peaks were observed when the IrNPs-SWCNT electrode was scanned in alkaline media, showing the strong electro- catalytic activity toward glucose oxidation. Ampero- metric measurements showed a high sensitivity of 63 μAcm -2 mM -1 and a detection limit of 17 μM; further, the measurements showed a linear range of 0.59-14 mM. To improve the selectivity of the electrode, the prepared IrNPs-SWCNT film electrode was coated using a 1.0% Nafion aqueous solution. When the elec- trodes were exposed to interfering substances such as uric acid and ascorbic acid, there were no significant signals observed from these substances, indicating that Nafion is an effective permselective polymer barrier. The sensitivity of the Nafion-coated electrode was 23 μAcm -2 mM -1 and the detection limit was 47 μM. In addition, the electro-catalytic activity of the Nafion- coated electrode was still stable after 50 cycles in the presence of a 3.0 mM glucose solution as measured by CV. Keywords: Electrocatalysis, Iridium nanoparticles, Car- bon nanotubes, Electrochemical deposition, Glucose Introduction The study of the electro-catalytic oxidation of sugars for the development of high performance glucose sen- sors, which have many clinical and industrial applica- tions, is of great interest 1,2 . There are two main appro- aches for electrochemical glucose sensing: enzymatic and non-enzymatic 3 . The fabrication of enzymatic glu- cose sensors is based on the immobilization of enzymes onto the surface of a conducting electrode. Although enzyme-based glucose sensors offer good selectivity and high sensitivity due to the specificity of the enzy- mes, they suffer from thermal and chemical instabilit- ies associated with the intrinsic nature of enzymes. Additionally, the complexity involved in enzyme im- mobilization techniques further limits the applications of enzyme-based sensors. In contrast to enzyme-assist- ed glucose oxidation, the direct oxidation of glucose by non-enzymatic sensors avoids the problems assoc- iated with enzyme immobilization and has other advan- tages such as stability, simplicity, reproducibility, and elimination of oxygen-dependent limitations 4 . Nanoparticles (NPs) possess appealing electrical, optical, magnetic, and catalytic properties that cannot be achieved at the bulk level 5-8 . NPs have been used as functional materials in electrochemistry. The modi- fication of a conducting electrode with NPs leads to four major advantages: high effective surface area, Original Article Decoration of Carbon Nanotube Films with Iridium Nanoparticles and Their Electrochemical Characterization Muhammad Irfan 1 , Xuan-Hung Pham 1 , Kwi Nam Han 1 , Cheng Ai Li 1 , Myung Hyo Hong 1 & Gi Hun Seong 1, * Received: 12 March 2014 / Accepted: 15 May 2014 / Published online: 20 June 2014 � The Korean BioChip Society and Springer 2014 1 Department of Bionano Engineering, Hanyang University, Ansan 425-791, Korea *Correspondence and requests for materials should be addressed to G.H. Seong ( ghseong@hanyang.ac.kr)