Direct DNA Immobilization onto a Carbon Nanotube Modified Electrode: Study on the Influence of pH and Ionic Strength

Document Type : Research Paper


1 Biotechnology Division, Department of Molecular and Cell Biology, Faculty of Chemistry, University of Kashan, Kashan, Iran

2 Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, Iran



Over the past years, DNA biosensors have been developed to analyze DNA interaction and damage that have important applications in biotechnological researches. The immobilization of DNA onto a substrate is one key step for construction of DNA electrochemical biosensors. In this report, a direct approach has been described for immobilization of single strand DNA onto carboxylic acid-functionalized carbon nanotubes modified glassy carbon electrode. To do this, we first modified the glassy carbon electrode surface with MWCNT-COOH. The immersion of MWCNT-COOH/GCE in ss-DNA probe solution, with different pH and ionic strength, was followed by suitable interaction between amine group of ss-DNA bases and carboxylic groups of MWCNT-COOH. This interaction leads to successful ss-DNA immobilization on MWCNT-COOH that was confirmed by cyclic voltammetry, electrochemical impedance spectroscopy and atomic force microscopy. Immobilization of ss-DNA on the modified electrode increased the charge transfer resistant but decreased the peak current of redox probe ([Fe(CN)6]3-/4-). The result of cyclic voltammograms implicates that enhancements in the DNA immobilization are possible by adroit choice of low pH and high ionic strength. The standard free-energy of adsorption (ΔG°ads) was calculated from electrochemical impedance spectroscopy data (-47.75 kJ mol-1) and was confirmed covalent bond formation. atomic force microscopy topographic images demonstrate increased surface roughness after ss-DNA immobilization. Results offer a simple, rapid and low-cost of DNA immobilization strategy can be opportunities to design of novel nucleic acid biosensors.


1. Malhotra BD, Singhal R, Chaubey A, Sharma SK, Kumar A., Recent trends in biosensors. Curr. Appl. Phys. 2005; 5(2): 92–97.
2. Sassolas A, Leca-Bouvier BD, Blum LJ., DNA biosensors and microarrays. Chem. Rev. 2008; 108(1): 109–139.
3. Odenthal KJ, Gooding JJ., An introduction to electrochemical DNA biosensors. Analyst. 2007; 132(7): 603–610.
4. Mashhadizadeh M. H., Pourtaghavi Talemi R., A new methodology for electrostatic immobilization of a non-labeled single strand DNA onto a self-assembled diazonium modified gold electrode and detection of its hybridization by differential pulse voltammetry. Talanta. 2013; 103: 344–348.
5. Ge C, Liao J, Yu W, Gu N., Electric potential control of DNA immobilization on gold electrode. Biosens. Bioelectron. 2003; 18(1): 53–58.
6. Lin X, Jiang X, Lu L., DNA deposition on carbon electrodes under controlled dc potentials. Biosens. Bioelectron. 2005; 20(9): 1709–1717.
7. Wang F, Xu Y, Wang L, Lu K, Ye B., Immobilization of DNA on a glassy carbon electrode based on Langmuir – Blodgett technique : application to the detection of epinephrine. J Solid State Electrochem. 2012; 16(6): 2127–2133.
8. Bonanni A, Pividori MI, Valle MD., Application of the avidin-biotin interaction to immobilize DNA in the development of electrochemical impedance genosensors. Anal. Bioanal. Chem. 2007; 389(3): 851–861.
9. Fuentes M, Mateo C, García L, Tercero JC, Guisán JM, Fernández-Lafuente R., Directed covalent immobilization of aminated DNA probes on aminated plates. Biomacromolecules. 2004; 5(3): 883–888.
10. Marie R, Schmid S, Johansson A, Ejsing L, Nordström M, Häfliger D., Immobilisation of DNA to polymerised SU-8 photoresist. Biosens. Bioelectron. 2006; 21(7): 1327–1332.
11. Kannoujia DK, Ali S, Nahar P., Single-step covalent immobilization of oligonucleotides onto solid surface. Anal. Methods. 2010; 2(3): 212–216.
12. Ulianas A, Heng LY, Abu Hanifah S, Ling TL., An electrochemical DNA microbiosensor based on succinimide-modified acrylic microspheres. Sensors. 2012; 12(5): 5445–5460.
13. Pividori MI, Merkoçi A, Alegret S., Electrochemical genosensor design: immobilisation of oligonucleotides onto transducer surfaces and detection methods. Biosens. Bioelectron. 2000; 15(5): 291–303.
14. Zhu C, Yang G, Li H, Du D, Lin Y., Electrochemical sensors and biosensors based on nanomaterials and nanostructures. Anal. Chem. 2015; 87(1): 230–249.
15. Balasubramanian K, Burghard M., Biosensors based on carbon nanotubes. Anal. Bioanal. Chem. 2006; 385(3): 452–468.
16. Wang J., Carbon-nanotube based electrochemical biosensors: A review. Electroanalysis. 2005; 17(1): 7–14.
17. Mahar B, Laslau C, Yip R, Sun Y., Development of carbon nanotube-based sensors — A review. IEEE Sens. J. 2007; 7(2): 266–284.
18. Vashist SK, Zheng D, Al-Rubeaan K, Luong JHT, Sheu FS., Advances in carbon nanotube based electrochemical sensors for bioanalytical applications. Biotechnol. Adv. Elsevier Inc. 2011; 29(2): 169–188.
19. Daniel S, Rao TP, Rao KS, Rani SU, Naidu GRK, Lee HY., A review of DNA functionalized/grafted carbon nanotubes and their characterization. Sens. Actuat B-Chem. 2007; 122(2): 672–82.
20. Cai H, Cao X, Jiang Y, He P, Fang Y., Carbon nanotube-enhanced electrochemical DNA biosensor for DNA hybridization detection. Anal. Bioanal. Chem. 2003; 375(2): 287–293.
21. Zhou LY, Zhang XY, Wang GL, Jiao XX, Luo HQ, Li NB., A simple and label-free electrochemical biosensor for DNA detection based on the super-sandwich assay. Analyst. 2012; 137(21): 5071–5075.
22. Zhang X, Servos MR, Liu J., Fast pH-assisted functionalization of silver nanoparticles with monothiolated DNA. Chem. Commun. 2012; 48(81): 10114–10116.
23. Zhang X, Servos MR, Liu J., Instantaneous and quantitative functionalization of gold nanoparticles with thiolated DNA using a pH-assisted and surfactant-free route. J. Am. Chem. Soc. 2012; 134(17): 7266–7269.
24. Vandeventer PE, Lin JS, Zwang TJ, Nadim A, Johal MS, Niemz A., Multiphasic DNA adsorption to silica surfaces under varying buffer, pH, and ionic strength conditions. J. Phys. Chem. B. 2012; 116(19):5661–5670.
25. Gao ZF, Gao JB, Zhou LY, Zhang Y, Si JC, Luo HQ., Rapid assembly of ssDNA on gold electrode surfaces at low pH and high salt concentration conditions. RSC Adv. 2013; 3(30): 12334–12340.
26. Karimi S, Ghourchian H, Rahimi P, Rafiee-Pour HA., , A nanocomposite based biosensor for cholesterol determination. Anal. Methods. 2012; 4(10): 3225–3231.
27. Perez LD, Zuluaga MA, Kyu T, Mark JE, Lopez BL., Preparation, characterization, and physical properties of multiwall carbon nanotube/elastomer composites. Polym. Eng. Sci. 2009; 49(5): 866–874.
28. Baykal A, Senel M, Unal B, Karaoğlu E, Sözeri H, Toprak MS., Acid functionalized multiwall carbon nanotube/magnetite (MWCNT)-COOH/Fe3O4 hybrid: synthesis, characterization and conductivity evaluation. J. Inorg. Organomet. Polym. 2013; 23(3): 726–735.
29. Luo H, Shi Z, Li N, Gu Z, Zhuang Q., Investigation of the electrochemical and electrocatalytic behavior of single-wall carbon nanotube film on a glassy carbon electrode. Anal. chem. 2001; 73(5): 915–920.
30. Wang HS, Ju HX, Chen HY., Voltammetric behavior and detection of DNA at electrochemically pretreated glassy carbon electrode. Electroanalysis. 2001; 13(13): 1105–1109.
31. Luo H, Li S, Guo ZX, He N, Dai L., Redox couple of DNA on multiwalled carbon nanotube modified electrode. Electroanalysis. 2009;21(14): 1641–1645.
32. Bandarenka AS., Exploring the interfaces between metal electrodes and aqueous electrolytes with electrochemical impedance spectroscopy. Analyst. 2013; 138(19): 5540–5554.
33. Mohan S, Nigam P, Prakash R., A label-free genosensor for BRCA1 related sequence based on impedance spectroscopy. Analyst. 2010; 135(11): 2887–2893.
34. Randviir EP, Banks CE., Electrochemical impedance spectroscopy : an overview of bioanalytical applications. Anal. Methods. 2013; 5(5): 1098–1115.
35. Cheng MS, Chee-Seng T., Novel biosensing methodologies for ultrasensitive detection of viruses. Analyst. 2013; 138(21): 6219–6229.
36. Bard AJ, Faulkner LR., (2001), Electrochemical methods: fundamentals and applications. 2nd ed. New York: Wiley.
37. Ardila JA, Oliveira GG, Medeiros RA, Fatibello-Filho O., Square-wave adsorptive stripping voltammetric determination of nanomolar levels of bezafibrate using a glassy carbon electrode modified with multi-walled carbon nanotubes within a dihexadecyl hydrogen phosphate film. Analyst. 2014; 139(7): 1762–1768.
38. Shamsi MH, Kraatz HB., The effects of oligonucleotide overhangs on the surface hybridization in DNA films: an impedance study. Analyst. 2011; 136(15):3107–3112.
39. Cheng Y, Korolev N, Nordenskiöld L., Similarities and differences in interaction of K+ and Na+ with condensed ordered DNA. A molecular dynamics computer simulation study. Nucleic Acids Res. 2006;34(2):686–696.
40. Li Z, Niu T, Zhang Z, Feng G, Bi S., Effect of monovalent cations (Li+, Na+, K+, Cs+) on self-assembly of thiol-modified double-stranded and single-stranded DNA on gold electrode. Analyst. 2012; 137(7):1680–1691.
41. Doneux T, De Rache A, Triffaux E, Meunier A, Steichen M, Buess-Herman C., Optimization of the probe coverage in DNA biosensors by a one-step coadsorption procedure. ChemElectroChem. 2014; 1(1): 147–157.
42. Behpour M, Ghoreishi SM, Soltani N, Salavati-Niasari M, Hamadanian M, Gandomi A., Electrochemical and theoretical investigation on the corrosion inhibition of mild steel by thiosalicylaldehyde derivatives in hydrochloric acid solution. Corros. Sci. 2008; 50(8): 2172–2181.
43. Behpour M, Mohammadi N., Investigation of inhibition properties of aromatic thiol self-assembled monolayer for corrosion protection. Corros. Sci. 2012; 65:331–339.
44. Rouillat MH, Dugas V, Martin JR, Phaner-Goutorbe M., Characterization of DNA chips on the molecular scale before and after hybridization with an atomic force microscope. Appl. Surf. Sci. 2005; 252(5):1765–1771.
45. Li S, He P, Dong J, Guo Z, Dai L., DNA-directed self-assembling of carbon nanotubes. J. Am. Chem. Soc. 2005; 127(1):14–15.
46. Lallemand D, Rouillat MH, Dugas V, Chevolot Y, Souteyrand E, Phaner-Goutorbe M., AFM characterization of ss-DNA probes immobilization : a sequence effect on surface organization. J. Phy. Conf. Ser. 2007; 61(1):658–662.
47. Sánchez-pomales G, Rivera-vélez NE, Cabrera CR., (2007), DNA-mediated self-assembly of carbon nanotubes on gold. J. Phy. Conf. Ser. 2007; 61(1):1017–1021.
48. Majumder A, Khazaee M, Opitz J, Beyer E, Baraban L, Cuniberti G., Bio-functionalization of multi-walled carbon nanotubes. Phys. Chem. Chem. Phys. 2013; 15(40):17158–17164.