Nanostructured platform for the detection of Neisseria gonorrhoeae using electrochemical impedance spectroscopy and differential pulse voltammetry Renu Singh, Zimple Matharu, Avanish Kumar Srivastava, Seema Sood, Rajinder Kumar Gupta & Bansi Dhar Malhotra Microchimica Acta An International Journal on Analytical Micro- and Nanochemistry ISSN 0026-3672 Volume 177 Combined 1-2 Microchim Acta (2012) 177:201-210 DOI 10.1007/s00604-012-0765-x
1 23
Your article is protected by copyright and all rights are held exclusively by SpringerVerlag. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your work, please use the accepted author’s version for posting to your own website or your institution’s repository. You may further deposit the accepted author’s version on a funder’s repository at a funder’s request, provided it is not made publicly available until 12 months after publication.
1 23
Author's personal copy Microchim Acta (2012) 177:201–210 DOI 10.1007/s00604-012-0765-x
ORIGINAL PAPER
Nanostructured platform for the detection of Neisseria gonorrhoeae using electrochemical impedance spectroscopy and differential pulse voltammetry Renu Singh & Zimple Matharu & Avanish Kumar Srivastava & Seema Sood & Rajinder Kumar Gupta & Bansi Dhar Malhotra
Received: 12 October 2011 / Accepted: 9 January 2012 / Published online: 15 February 2012 # Springer-Verlag 2012
Abstract We report on a nanocomposite based genosensor for the detection of Neisseria gonorrhoeae, a bacterium causing the sexually transmitted disease gonorrhoea. Aminolabeled probe DNA was covalently immobilized on electrochemically prepared polyaniline and iron oxide (PANI-Fe3O4) nanocomposite film on an indium tin oxide (ITO) electrode. Scanning electron microscopy, transmission electron microscopy, electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) techniques have been employed to characterize surface of the modified electrode. The genosensor has detection limits of 1 ×10-15 M and 1×10-17 M, respectively, using the EIS and DPV techniques. Electronic supplementary material The online version of this article (doi:10.1007/s00604-012-0765-x) contains supplementary material, which is available to authorized users. R. Singh : Z. Matharu : A. K. Srivastava : B. D. Malhotra Department of Science & Technology Centre on Biomolecular Electronics, Biomedical Instrumentation Section, National Physical Laboratory (Council of Scientific & Industrial Research), Dr. K.S. Krishnan Marg, New Delhi 110012, India S. Sood Department of Microbiology, All India Institute of Medical Sciences, New Delhi 110002, India R. Singh : R. K. Gupta School of Biotechnology, Guru Gobind Singh Indraprastha University, Kashmere Gate, Delhi 110006, India B. D. Malhotra (*) Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042, India e-mail:
[email protected]
This biosensor can discriminate a complementary sequence from a single-base mismatch and from non-complementary DNA, and has been utilized for detection of DNA extracted from N. gonorrhoeae culture, and from patient samples with N. gonorrhoeae. It is found to exhibit good specificity for N. gonorrhoeae species and shows no response towards nongonorrhoeae type of Neisseria species (NgNs) and other gram-negative bacterias (GNBs). The affinity constant for hybridization calculated using the Langmuir adsorption isotherm model is found to be 3.39×108 M-1. Keywords Neisseria gonorrhoeae . Sexually transmitted disease . Polyaniline-Fe3O4 nanocomposite . Electrochemical DNA sensor . Impedance spectroscopy
Introduction There is increased interest towards tailoring of the micro and nanostructured materials for fabrication of advanced micro and nanobiodevices [1]. In this context, conducting polymers (CPs) are an excellent choice because of their robustness, flexibility, cost-effectiveness, ease-of-synthesis and fast electron transferring properties due to their conjugated structure [2]. Among the various CPs, polyaniline (PANI) is one of the most extensively studied CP due to its electrical conductivity, thermal and environmental stability, ease-of-preparation and electrochemical properties [3–8]. In spite of these interesting characteristics, PANI has found limited biosensing applications till date since it is not electrochemically active in neutral solution, and exhibits redox characteristics only in an acidic medium (pH
