Copyright © 2014 American Scientific Publishers All rights reserved Printed in the United States of America Article Journal of Nanoscience and Nanotechnology Vol. 14, 1–12, 2014 www.aspbs.com/jnn Simple Electro-Assisted Immobilization of Ciprofloxacin on Carbon Nanotube Modified Electrodes: Its Selective Hydrogen Peroxide Electrocatalysis Sundaram Sornambikai and Annamalai Senthil Kumar ∗ Environmental and Analytical Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632014, India Ciprofloxacin (Cf) is a synthetic fourth generation fluoroquinolone class antibiotic used for the treat- ment of gram-positive, gram-negative and mycobacterium species infections. Electrochemical char- acteristic of the Cf antibiotic on carbon nanotube modified glassy carbon electrode (GCE/CNT) in pH 7 phosphate buffer solution has been investigated. Electrochemically oxidized radical byproduct of the Cf drug, which is formed as intermediate, gets immobilized on the GCE/CNT (GCE/Cf@CNT) and showed stable and well defined surface confined redox peak at - 0.220 V versus Ag/AgCl. Control electrochemical experiment with unmodified GCE failed to show any such immobilization and redox features. Physicochemical characterizations of the Cf@CNT by transmission electron microscope, scanning electron microscope, infrared spectroscopy, UV-Vis and gas chromatogra- phy coupled mass spectroscopic analyses of Cf@CNT collectively revealed presence of native form of the Cf antibiotic molecule onto the CNT. The interaction between the Cf molecule and the CNT tubes are revealed from the decreased intensity in the Raman spectrum. The GCE/Cf@CNT showed excellent electrocatalytic response to hydrogen peroxide reduction reaction in pH 7 phos- phate buffer solution. Amperometric i –t analysis for the detection of H 2 O 2 showed a current linearity plot upto [H 2 O 2 ] = 200 M at an applied potential - 0.1 V versus Ag/AgCl with a current sensitivity value 678 A mM -1 cm -2 . No interferences were noticed with ascorbic acid, uric acid, cysteine and nitrite. The present study can be highly helpful to understand the interaction between the Cf and H 2 O 2 in physiological systems and for the removal of Cf from the antibiotic polluted water samples especially in the aquaculture and agricultural systems. Keywords: Ciprofloxacin, Immobilization, Carbon Nanotube Hybrids, Electro-Catalysis, Hydrogen Peroxide. 1. INTRODUCTION The immobilization of antibiotic on nanomaterials and their enhanced physical properties such as sustained drug release, stabilization of active form of the drug, well defined electron-transfer behavior and enhanced microbi- ological function gained tremendous attention in recent years. 1–4 Recently, matrices such as carbon nanotubes (CNT), 5–10 core shell silica, certain polymers and gold nanoparticles were found to be efficient biocompati- ble nanomaterials those have engrossed great interest in nanobiotechnology. These matrices possess generic transporting ability of the porous material and wide range of functional properties. 1–3 Some of available ∗ Author to whom correspondence should be addressed. references for the preparation and applications of hybrid- antibiotic materials are; amoxicillin (AMX) immobilized carbon nanotubes for enhanced antimicrobial activity, 4 ciprofloxacin (Cf) antibiotic incorporated-silica nanoshell for enhanced antibacterial action against E.coli DH5x and L.lactis MG 1363, 11 Cf doped electropolymerised polypyr- role outer shell layer with poly(3,4-ethylenedioxythioene) poly(styrenesulfonate) inner core fibre for electrical con- trolled release of Cf, 12 13 Cf capped gold nanoparti- cle (Cf@Au) 14 and in situ precipitation of calcium phosphate and Cf crystals during the chitosan hydro- gel formation 15 for drug delivery application, gentamycin antibiotic loaded silica-hydroxyapatite matrix through poly(lactide-co-glucolide) scaffold microspheres for drug delivery in bone replacement, 16 Hydroxyapatite-Alginate J. Nanosci. Nanotechnol. 2014, Vol. 14, No. xx 1533-4880/2014/14/001/012 doi:10.1166/jnn.2014.9358 1