Electrochemical Sensing Platform Based on Single-Walled Carbon Nanotubes (SWCNTs)/Gold Nanoparticles (AuNps) Nanocomposite Antonella Curulli & Chiara Bianchini & Daniela Zane Published online: 15 October 2011 # Springer Science+Business Media, LLC 2011 Abstract In this paper, the electrochemical characterization and the application of a single-walled carbon nanotubes (SWCNTs)/gold nanoparticles (AuNps) nanocomposite- modified glassy carbon (GC) electrode for the preparation of electrochemical sensing platform are proposed. Inorganic electroactive compounds (i.e., probe molecules, potassium ferricyanide K 3 Fe(CN) 6 and hexaammine ruthenium(III) chloride [Ru(NH 3 ) 6 ]Cl 3 ) and molecules of biological interest such as dopamine (DA), catechol, and serotonin were employed to study their electrochemical responses at SWCNTs/AuNps/GC electrode and to compare them with those of GC bare electrode and of GC-modified electrode with SWCNTs or AuNps. The electrochemical behavior of DA, catechol, and serotonin is also investigated at two different pH values (pH 4.00 and 7.00). By comparing their electrochemical responses at SWCNTs/AuNps/GC elec- trode with those at conventional GC electrode, we observed different amplifications of the electrochemical signal ranging from 56% (pH 7.00) to 35% (pH 4.00) for catechol, from 73% (pH 7.00) to 35% (pH 4.00) for DA, and from 452% (pH 4.00) to 703% (pH 7.00) for serotonin; so, the nanocomposite resulted a promising material for a sensing platform. Keywords Nanomaterials . Gold nanoparticles . Carbon nanotubes . Nanocomposite . Sensing platform Introduction Transition metals such as gold, platinum, silver, copper, and nickel exhibit their high catalytic activity for many chemical reactions. With an ease of miniaturization to nanoscale dimensions, nanoparticles have been used in various chemical/biochemical sensing platform and in electrocatalysis [1]. Indeed, the electrochemical behavior and the applications of nanoparticles have witnessed a significant growth in the last years, especially because of their simple synthesis procedures [2–4], using various reducing agents coupled with a metal salt. Especially, gold nanoparticles (AuNps) represent excel- lent biocompatibility and display unique structural, elec- tronic and catalytic properties which have made them a very attractive material for sensing and electrocatalysis [1]. As is well known, AuNps exhibiting excellent cata- lytic activity have received considerable attention due to their high surface area-to-volume ratio and their interface- dominated properties, which significantly differ from their bulk counterparts [1]. This interest in the catalytic properties of AuNps has increased rapidly and AuNps- modified electrochemical interfaces have been widely used as enhancing for the development of electrochemical sensors [1]. Since the discovery of carbon nanotubes (CNTs) [5], several unique properties of these exciting materials have been reported [6]. Among a plethora of diversified A. Curulli (*) : D. Zane ISMN CNR Istituto per lo Studio dei Materiali Nanostrutturati Consiglio Nazionale delle Ricerche, Via del Castro Laurenziano 7, 00161 Rome, Italy e-mail: antonella.curulli@ismn.cnr.it A. Curulli e-mail: antonella.curulli@uniroma1.it C. Bianchini Dipartimento Ingegneria Materiali e Ambiente Facoltà di Ingegneria, Università di Roma Sapienza, Via del Castro Laurenziano 7, 00161 Rome, Italy Electrocatal (2012) 3:30–38 DOI 10.1007/s12678-011-0073-y