The role of DNA in PANI–DNA hybrid: Template and dopant

doi:10.1016/j.polymer.2009.07.024

Polymer

Volume 50, Issue 19, 10 September 2009, Pages 4529-4534

https://doi.org/10.1016/j.polymer.2009.07.024 Get rights and content

Abstract

We exposed a novel method by using DNA as the dopant as well as template at the same time to prepare PANI–DNA hybrid micro/nanowires with conductivity as high as ∼10⁻² S cm⁻¹. The high conductivity is due to the co-doping function of DNA with HCl produced by FeCl₃. It is found that the morphology and conductivity of the PANI–DNA hybrids are affected by the [DNA]/[AN] ratio due to the co-operation and competition of DAN's dopant and template function, and the role of DNA in PANI–DNA hybrid varies with the changing of [DNA/[AN] ratios.

Graphical abstract

Introduction

Bio-molecule templates give new opportunities to construct novel nano-materials with special features [1], [2], [3]. Among those bio-templates, deoxyribonucleic acid (DNA) has recently received great attention because its special self-recognition and self-assembly properties offer unique advantages for design and synthesis of multifunctional bio-active molecular complex [4], [5], [6]. In addition, micro/nanostructures of conducting polymers, such as polyaniline (PANI) or polypyrrole (PPy), have also drawn great interests due to their unique chemical and physical properties [7], [8], [9], [10], [11] including controllable chemical and electrical properties by simply changing the oxidation and proton state, facile and low cost of preparation, and excellent environmental stability. These unique properties lead to the wide applications of conducting polymers in micro/nano-materials [12], [13], [14] and devices, such as light-emitting diodes [15], [16], transistors [17], chemical and biosensors [18], [19], solar cells [20], electrochromic devices [21] and memory devices [22]. It is therefore reasonable to be expecting that combination of the reversible doping/de-doping feature of conducting polymers with molecular-recognition and self-assembly characteristic of DNA [23], [24] might expose wide applications in molecular electronic device and quantum functional materials [25]. So far, a series of articles on nanostructured hybrids of conducting polymers with DNA have been reported. For instance, Y.F. Ma and co-workers [26] reported a strategy for the fabrication of conducting polymer nanowires on thermally oxidized Si surface by using DNA as the hard-template. Nagarajan et al. [27] used DNA as the hard-template to prepare water-soluble PANI–DNA complexes, in which PANI was wrapped around the DNA and it can reversibly control the secondary structure of DNA from the native form to an over-wound polymorph by simply changing the redox state of PANI. Moreover, a hybrid of poly(o-methoxy-aniline) with DNA, which has a needle-like morphology and conductivity of ca. 10⁻⁷ S cm⁻¹, has been reported by Dawn et al. [24] Except for PANI–DNA complexes, PPy–DNA hybrids have also been reported [28]. As to our best knowledge, DNA in the previous papers mainly was used as the hard-template and the conductivity of the resultant nanostructured hybrid was quite poor [24], [26]. Consequently, exploring new function of DNA for enhancing conductivity of the conducting polymer hybrids with DNA is urgently necessary.

As Scheme 1 shows [28], DNA molecule has phosphate groups which can act as the dopant of PANIs due to their proton doping mechanism [7], suggesting that the doping function of DNA might be imposed. Recently, Wan et al. [29], [30], [31] reported a simplified template-free method (STFM) to prepare PANI nanotubes with 20–30 nm in diameter and PANI derivatives with hollow microspheres in shape by using FeCl₃ as both oxidant and dopant in the absence of acidic dopant and hard-template. This STFM is the simplest approach to prepare PANI nanostructures at the current time because only aniline monomer and oxidant are required.

Herein, we report a novel approach to prepare self-assembly microwires of PANI–DNA hybrid with conductivity as high as 1.3 × 10⁻² S cm⁻¹ by using DNA as dopant as well as hard- and soft-template. Interestingly, these hybrid microwires are constructed by the nanofibers with about 20–30 nm in diameter. Moreover, the morphology and conductivity of the hybrid are greatly affected by the mass ratio of DNA to aniline. The role of DNA as dopant and template is discussed based on the molecular characterizations, as measured by FTIR and UV–vis spectrum, X-ray photoelectron spectroscopy (XPS), synchronous energy dispersive X-ray (EDX) and X-ray diffraction (XRD), as well as the conductivity measured by a four-probe method.

Section snippets

Materials

Deoxyribonucleic acid (DNA) from salmon test was purchased from Sigma Chemical Co., USA (D-1626, type III, sodium salt). All the experiments involving DNA were performed under sterilized conditions. Before each reaction, DNA was firstly dissolved in the water under magnetic stirring to form a homogeneous and transparent aqueous solution. Aniline (A.R., Beijing Mashi Fine Chem. Co.) was distilled under reduced pressure and kept refrigerated under nitrogen prior to use. Other reagents, such as

Results and discussion

Fig. 1 shows SEM images of PANI and the PANI–DNA hybrids synthesized at different mass ratios of DNA to aniline, which are represented as [DNA]/[AN] ratios. As shown in Fig. 1a, the PANI, which was synthesized in the absence of DNA, is fibril morphology in shape with 20–30 nm in diameter and about 200 nm in length that is consistent with the previous results [29]. At a lower [DNA]/[AN] ratio (e.g. 0.011), the PANI–DNA is composed of nanofibers with about 30–50 nm in diameter and ∼100 nm in length (

Conclusion

In summary, we expose a novel method by using DNA as the dopant as well as hard- and soft-template to prepare PANI–DNA hybrid micro/nanowires with conductivity as high as ∼10⁻² S cm⁻¹. Both the morphology and conductivity of the PANI–DNA hybrids are affected by the [DNA]/[AN] ratios. It is proved that the change of conductivity with the [DNA]/[AN] ratios results from the competition of DNA and HCl as the co-dopant. On the other hand, the co-operation and competition of DAN as the soft- and

Acknowledgements

This project was supported by The National Nature Sciences Foundation of China (No. 50533030) and The Beijing Nova Programme (2007B010), and we would like to thank Prof. Wei Yen at the Centre for Advanced Polymers and Materials Chemistry, Department of Chemistry, Drexel University, Philadelphia, USA for providing DNA samples.

References (45)

J. Luo et al.
Polymer
(2007)
E. Komarova et al.
Biosens Bioelectron
(2005)
E.T. Kang et al.
Prog Polym Sci
(1998)
J. Stejskal et al.
Synth Met
(1998)
R. Gasparac et al.
Nano Lett
(2004)
N. Ma et al.
J Am Chem Soc
(2006)
A.T. Krummel et al.
J Phys Chem B
(2008)
Y. Masanori et al.
Polymer
(2008)
K. Ramanathan et al.
J Am Chem Soc
(2005)
S. Nayak et al.
Angew Chem Int Ed
(2005)

A.G. MacDiarmid

Angew Chem Int Ed

(2001)

X.H. Chen et al.

J. Nanosci Nanotechnol

(2006)

Y. Li et al.

J Phys Chem B

(2005)

T.S. Lawrence et al.

J Phys Chem A

(2000)

L.D. Qin et al.

Science

(2005)

D.J. Lipomi et al.

Nano Lett

(2008)

Y. Berdichevsky et al.

Adv Mater

(2006)

C.D. Müller et al.

Nature

(2003)

W. Ma et al.

Adv Mater

(2005)

A.M. Jeffrey et al.

J Polym Sci Part B Polym Phys

(2003)

M.M. Ayad et al.

Polym Adv Technol

(2008)

M. Aoife et al.

Electroanalysis

(2005)

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The role of DNA in PANI–DNA hybrid: Template and dopant

Abstract

Graphical abstract

Introduction

Section snippets

Materials

Results and discussion

Conclusion

Acknowledgements

Polymer

Biosens Bioelectron

Prog Polym Sci

Synth Met

Nano Lett

J Am Chem Soc

J Phys Chem B

Polymer

J Am Chem Soc

Angew Chem Int Ed

Angew Chem Int Ed

J. Nanosci Nanotechnol

J Phys Chem B

J Phys Chem A

Science

Nano Lett

Adv Mater

Nature

Adv Mater

J Polym Sci Part B Polym Phys

Polym Adv Technol

Electroanalysis