Materials Science and Engineering B 169 (2010) 169–173 Contents lists available at ScienceDirect Materials Science and Engineering B journal homepage: www.elsevier.com/locate/mseb Electrochemical investigation of biomolecular interactions between platinum derivatives and DNA by carbon nanotubes modified sensors Ece Yapasan a,b , Ayfer Caliskan b , Hakan Karadeniz b , Arzum Erdem b,∗ a Izmir Institute of Technology, Faculty of Science, Chemistry Department, 35430 Urla, Izmir, Turkey b Ege University, Faculty of Pharmacy, Analytical Chemistry Department, 35100 Bornova, Izmir, Turkey article info Article history: Received 2 June 2009 Received in revised form 12 October 2009 Accepted 16 October 2009 Keywords: Carbon nanotubes DNA interactions Electrochemical impedance spectroscopy Differential pulse voltammetry cis-Diamminedichloroplatinum(II) Oxaliplatin abstract The biomolecular interactions of platinum derivatives widely used as anticancer drugs: cis- diamminedichloroplatinum(II) and oxaliplatin with calf thymus double-stranded DNA were studied using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) in combination with single-walled carbon nanotubes modified graphite electrode (SWCNTs-GE) and unmodified graphite electrode (bare GE). The performance of these biomolecular interactions were explored at the electrode surface by monitoring the changes at guanine oxidation signal in terms of optimum interaction times by comparing the results of SWCNTs-GE with bare one. The features of these electrochemical sensors based on carbon nanotubes for monitoring of biomolecular interactions were discussed and compared with the earlier conventional ones. © 2009 Elsevier B.V. All rights reserved. 1. Introduction During early sixties, many electrochemical approaches have been developed for analyzing or quantification of nucleic acids and its interactions [1–13]. Various types of affinity biosen- sors as “Genosensor” for nucleic acid recognition processes have been rapidly developed incorporating different nanoma- terials for the detection of specific nucleic acid sequences related with genetic and infectious diseases. Immediate appli- cations will include direct quantification of DNA samples for use in sequencing or polymerase chain reactions, or pharma- ceutical testing and quality control. Detection of biomolecular interaction of some anticancer drugs (Epirubicin, Mitoxantrone, Echinomycin, Daunomycin, etc.), several kinds of carcinogens (Benzo[a]pyrene, etc.) and toxins (Microcystin, etc.) with DNA is the major branch of electrochemical biosensors. Variety of tech- niques have been used to detect interaction of cancer drugs with DNA [3–5]. Nanotechnology has a key importance for the development of challenging tools, including biosensor technologies. Carbon nanotubes were discovered in 1991 by Lijima [14]. They are large macromolecules that are unique for their size, shape, and remark- able physical properties. Their intriguing structures have sparked ∗ Corresponding author. Tel.: +90 232 343 4000x5131; fax: +90 232 388 5258. E-mail addresses: arzum.erdem@ege.edu.tr, arzume@hotmail.com (A. Erdem). much excitement in the recent years and a large amount of research has been dedicated to their understanding. The nanotubes have a very broad range of electronic, thermal, and structural proper- ties that change depending on the different kinds of nanotube. To make things more interesting, besides having a single cylindrical wall (SWNTs), the nanotubes can have multiple walls (MWNTs) cylinders inside the other cylinders. The investigations at chemistry side based on DNA–drug inter- actions may provide new compounds, that could be tested for an effect on a biochemical target, and also used as promising hybridization indicator in combination with DNA hybridization biosensors based on nanomaterials, which will further become DNA microchip systems [6,12,13,15]. Recent advancements in the development of biosensors with the advances in nanotechnology provide novel tools to develop new techniques for monitoring biomolecular recognition events at the solid surfaces, or in the solution phase. Typical applications include environmental monitoring and control, DNA diagnosis, and chem- ical measurements in the agriculture, food and drug industries [6,12,13,15–24]. Electrochemical detection of nucleic acids related to the specific gene for the breast cancer BRCA1 mutation provided the enhanced signals contrast to bare one by using MWNT modi- fied glassy carbon electrode [25]. A sensitive and low cost detection of specific DNA hybridization at the surface of MWCNT modified disposable graphite electrode was performed employing a simple electrochemical protocol by Erdem et al. [6]. In another work of our group, the application of MWCNT-screen printed electrodes was 0921-5107/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.mseb.2009.10.024