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Carbon composite micro- and nano-tubes-based electrodes for detection of nucleic acids.

Prasek J, Huska D, Jasek O, Zajickova L, Trnkova L, Adam V, Kizek R, Hubalek J - Nanoscale Res Lett (2011)

Bottom Line: MWCNTs were successfully prepared by using plasma enhanced chemical vapour deposition.Carbon composite electrode prepared from a mixture of glassy and spherical carbon powder and MWCNTs had the highest sensitivity to nucleic acids.Other interesting result is the fact that we were able to distinguish signals for all bases using this electrode.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microelectronics, Brno University of Technology, Technicka 10, CZ-61600 Brno, Czech Republic. hubalek@feec.vutbr.cz.

ABSTRACT
The first aim of this study was to fabricate vertically aligned multiwalled carbon nanotubes (MWCNTs). MWCNTs were successfully prepared by using plasma enhanced chemical vapour deposition. Further, three carbon composite electrodes with different content of carbon particles with various shapes and sizes were prepared and tested on measuring of nucleic acids. The dependences of adenine peak height on the concentration of nucleic acid sample were measured. Carbon composite electrode prepared from a mixture of glassy and spherical carbon powder and MWCNTs had the highest sensitivity to nucleic acids. Other interesting result is the fact that we were able to distinguish signals for all bases using this electrode.

No MeSH data available.


Related in: MedlinePlus

Cyclic voltammetry. The dependences of adenine peak height on ln of scan rates (50, 100, 200, 400, 600 and 800 mV/s) measured at (A) microcarbon, (B) nanocarbon and (C) nanocarbon II. In insets: dependencies of adenine peak potentials on ln of scan rate. Square wave voltammetry. SW voltammograms of (D) single strand oligonucleotide influenza (13 μg/mL), and (E) double strand genomic DNA (15 μg/mL). In insets: signals of all nucleic acid bases after baseline correction and smoothing of raw data.
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Figure 2: Cyclic voltammetry. The dependences of adenine peak height on ln of scan rates (50, 100, 200, 400, 600 and 800 mV/s) measured at (A) microcarbon, (B) nanocarbon and (C) nanocarbon II. In insets: dependencies of adenine peak potentials on ln of scan rate. Square wave voltammetry. SW voltammograms of (D) single strand oligonucleotide influenza (13 μg/mL), and (E) double strand genomic DNA (15 μg/mL). In insets: signals of all nucleic acid bases after baseline correction and smoothing of raw data.

Mentions: Further, three carbon composite electrodes with different content of carbon particles with various shapes and sizes were prepared and tested on measuring of nucleic acids. The first carbon composite electrode (called as "microcarbon") was made of 90% "glassy carbon powder," where the particles are from glassy carbon material and they have spherical shape 2 μm (w/w, Sigma-Aldrich, USA) and 10% mineral oil (m/w, Sigma-Aldrich; free of DNase, RNase, and protease). The second one (called as "nanocarbon") was made of 60% "glassy carbon powder" (w/w, Sigma-Aldrich), 30% powdered cylinder carbon nanotubes (w/w, Sigma-Aldrich) and 10% mineral oil (w/w, Sigma-Aldrich). The third one was made of (called as "nanocarbon II") 60% "glassy carbon powder" (w/w, Sigma-Aldrich), 30% above prepared MWCNTs and 10% mineral oil. These prepared materials were housed in a teflon body having a 2.5-mm-diameter disk surface. Before measurements, the electrode surface was renewed by polishing with a soft filter paper in preparation for measurement [9-11], which was carried out in the presence of 0.2 M acetate buffer (5.0). The prepared carbon composite electrodes were used in the following experiments, in which genomic DNA isolated from salmon (genomic salmon DNA) and oligonucleotide single strand from influenza (ODN influenza; 5'-CAG TCG CAA GGA CTA ATC TGT TTG-3') were analysed. Carbon and/or graphite are of particular interest but its voltammetric response is complex as a result of its heterogeneous surface structure, where it exhibits both edge and basal plane sites and, depending upon how the graphite is aligned, the electrode may be predominantly basal or edge plane in character [12]. Numerous authors have been utilizing carbon nanotubes for the electro-oxidation of DNA [13]. The edge plane sites on graphite are generally accepted to exhibit far greater rates of electron transfer as compared to the basal plane sites. Further, the adsorption of species on the graphite surfaces also differs at the two sites [14]. Therefore, the versatility of the electrode was tested. Cyclic voltammetry was used for the detection of two nucleic acids' samples mentioned above and the basic electrochemical behaviour of nucleic acids at the surface of the above prepared carbon composite electrodes were studied. It is known that that cytosine, adenine, thymine and guanine give signals at carbon electrodes [15-17]. We found that both the nucleic acid samples gave all four signals corresponding to single bases at the tested electrodes. Adenine gave the highest signal; however, the sequence of height of the other bases measured on the electrodes differed. Guanine was the second-most electroactive bases at nanocarbon electrode followed by thymine and cytosine as well as at nanocarbon II electrode, but the height of cytosine was higher compared with thymine. At the surface of microcarbon electrode, the height of bases decreased in the following order thymine, guanine and cytosine. These changes can be associated with different surfaces and its affinity to single bases, which can subsequently influence the redox processes. To study the behaviour of bases on the surface of the electrodes, the dependences of adenine peak height on scan rate (50, 100, 200, 400, 600 and 800 mV/s) were determined. The logarithmic dependences are shown in Figure 2A-C for microcarbon, nanocarbon and nanocarbon II electrodes, respectively. It clearly follows from the results obtained that ODN influenza gave higher signal compared with genomic salmon DNA except ODN influenza signal measured under 50 mV/s at nanocarbon II. If we compared the sharpness of the dependencies, then the sharpest were those measured at nanocarbon II electrode followed by nanocarbon electrode and microcarbon electrode. Moreover, the dependencies of adenine peak potentials on scan rate were determined and are shown in insets in Figure 2A-C for microcarbon, nanocarbon and nanocarbon II electrodes, respectively (R2 higher than 0.998). Based on both the logarithmic and linear dependencies, we found that the redox electrode process at all electrodes was diffusion-limited. Moreover, based on the Randles-Sevcik equation for a reversible and diffusion-controllable process, we estimated that the reaction exhibited nearly heterogeneous one-electron transfer. Moreover, the dependences of adenine peak height on concentration of nucleic acid sample were measured. The dependences were strictly linear for both nucleic acid samples with R2 higher than 0.996. The slope of the obtained curves enhanced as follows: nanocarbon II > nanocarbon > microcarbon. It clearly follows from the results obtained that carbon composite electrode prepared from the mixture of glassy and spherical carbon powder and MWCNTs had the highest sensitivity to nucleic acids. Based on these results, nanocarbon II electrodes were further utilized for detection of both the nucleic acids' samples (25 μg/mL) using square wave voltammetry (not shown). We were interested in the issue whether we could detect signals of all bases due to such high sensitivity. Both the nucleic acids samples (15 μg/mL) were detected, and all purine and pyrimidine bases signals were observed (Figure 2D, E, for ODN influenza and genomic salmon DNA, respectively); peak potential about G = 0.8 V; A = 1.05, T = 1.25 and C = 1.35 V. Signals of the genomic DNA were higher (approx. 30%) in comparison with the oligonucleotide. Another interesting result is the fact that we were able to clearly distinguish signals for all bases by using baseline correction and smoothing (insets in Figure 2D, E).


Carbon composite micro- and nano-tubes-based electrodes for detection of nucleic acids.

Prasek J, Huska D, Jasek O, Zajickova L, Trnkova L, Adam V, Kizek R, Hubalek J - Nanoscale Res Lett (2011)

Cyclic voltammetry. The dependences of adenine peak height on ln of scan rates (50, 100, 200, 400, 600 and 800 mV/s) measured at (A) microcarbon, (B) nanocarbon and (C) nanocarbon II. In insets: dependencies of adenine peak potentials on ln of scan rate. Square wave voltammetry. SW voltammograms of (D) single strand oligonucleotide influenza (13 μg/mL), and (E) double strand genomic DNA (15 μg/mL). In insets: signals of all nucleic acid bases after baseline correction and smoothing of raw data.
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Related In: Results  -  Collection

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Show All Figures
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Figure 2: Cyclic voltammetry. The dependences of adenine peak height on ln of scan rates (50, 100, 200, 400, 600 and 800 mV/s) measured at (A) microcarbon, (B) nanocarbon and (C) nanocarbon II. In insets: dependencies of adenine peak potentials on ln of scan rate. Square wave voltammetry. SW voltammograms of (D) single strand oligonucleotide influenza (13 μg/mL), and (E) double strand genomic DNA (15 μg/mL). In insets: signals of all nucleic acid bases after baseline correction and smoothing of raw data.
Mentions: Further, three carbon composite electrodes with different content of carbon particles with various shapes and sizes were prepared and tested on measuring of nucleic acids. The first carbon composite electrode (called as "microcarbon") was made of 90% "glassy carbon powder," where the particles are from glassy carbon material and they have spherical shape 2 μm (w/w, Sigma-Aldrich, USA) and 10% mineral oil (m/w, Sigma-Aldrich; free of DNase, RNase, and protease). The second one (called as "nanocarbon") was made of 60% "glassy carbon powder" (w/w, Sigma-Aldrich), 30% powdered cylinder carbon nanotubes (w/w, Sigma-Aldrich) and 10% mineral oil (w/w, Sigma-Aldrich). The third one was made of (called as "nanocarbon II") 60% "glassy carbon powder" (w/w, Sigma-Aldrich), 30% above prepared MWCNTs and 10% mineral oil. These prepared materials were housed in a teflon body having a 2.5-mm-diameter disk surface. Before measurements, the electrode surface was renewed by polishing with a soft filter paper in preparation for measurement [9-11], which was carried out in the presence of 0.2 M acetate buffer (5.0). The prepared carbon composite electrodes were used in the following experiments, in which genomic DNA isolated from salmon (genomic salmon DNA) and oligonucleotide single strand from influenza (ODN influenza; 5'-CAG TCG CAA GGA CTA ATC TGT TTG-3') were analysed. Carbon and/or graphite are of particular interest but its voltammetric response is complex as a result of its heterogeneous surface structure, where it exhibits both edge and basal plane sites and, depending upon how the graphite is aligned, the electrode may be predominantly basal or edge plane in character [12]. Numerous authors have been utilizing carbon nanotubes for the electro-oxidation of DNA [13]. The edge plane sites on graphite are generally accepted to exhibit far greater rates of electron transfer as compared to the basal plane sites. Further, the adsorption of species on the graphite surfaces also differs at the two sites [14]. Therefore, the versatility of the electrode was tested. Cyclic voltammetry was used for the detection of two nucleic acids' samples mentioned above and the basic electrochemical behaviour of nucleic acids at the surface of the above prepared carbon composite electrodes were studied. It is known that that cytosine, adenine, thymine and guanine give signals at carbon electrodes [15-17]. We found that both the nucleic acid samples gave all four signals corresponding to single bases at the tested electrodes. Adenine gave the highest signal; however, the sequence of height of the other bases measured on the electrodes differed. Guanine was the second-most electroactive bases at nanocarbon electrode followed by thymine and cytosine as well as at nanocarbon II electrode, but the height of cytosine was higher compared with thymine. At the surface of microcarbon electrode, the height of bases decreased in the following order thymine, guanine and cytosine. These changes can be associated with different surfaces and its affinity to single bases, which can subsequently influence the redox processes. To study the behaviour of bases on the surface of the electrodes, the dependences of adenine peak height on scan rate (50, 100, 200, 400, 600 and 800 mV/s) were determined. The logarithmic dependences are shown in Figure 2A-C for microcarbon, nanocarbon and nanocarbon II electrodes, respectively. It clearly follows from the results obtained that ODN influenza gave higher signal compared with genomic salmon DNA except ODN influenza signal measured under 50 mV/s at nanocarbon II. If we compared the sharpness of the dependencies, then the sharpest were those measured at nanocarbon II electrode followed by nanocarbon electrode and microcarbon electrode. Moreover, the dependencies of adenine peak potentials on scan rate were determined and are shown in insets in Figure 2A-C for microcarbon, nanocarbon and nanocarbon II electrodes, respectively (R2 higher than 0.998). Based on both the logarithmic and linear dependencies, we found that the redox electrode process at all electrodes was diffusion-limited. Moreover, based on the Randles-Sevcik equation for a reversible and diffusion-controllable process, we estimated that the reaction exhibited nearly heterogeneous one-electron transfer. Moreover, the dependences of adenine peak height on concentration of nucleic acid sample were measured. The dependences were strictly linear for both nucleic acid samples with R2 higher than 0.996. The slope of the obtained curves enhanced as follows: nanocarbon II > nanocarbon > microcarbon. It clearly follows from the results obtained that carbon composite electrode prepared from the mixture of glassy and spherical carbon powder and MWCNTs had the highest sensitivity to nucleic acids. Based on these results, nanocarbon II electrodes were further utilized for detection of both the nucleic acids' samples (25 μg/mL) using square wave voltammetry (not shown). We were interested in the issue whether we could detect signals of all bases due to such high sensitivity. Both the nucleic acids samples (15 μg/mL) were detected, and all purine and pyrimidine bases signals were observed (Figure 2D, E, for ODN influenza and genomic salmon DNA, respectively); peak potential about G = 0.8 V; A = 1.05, T = 1.25 and C = 1.35 V. Signals of the genomic DNA were higher (approx. 30%) in comparison with the oligonucleotide. Another interesting result is the fact that we were able to clearly distinguish signals for all bases by using baseline correction and smoothing (insets in Figure 2D, E).

Bottom Line: MWCNTs were successfully prepared by using plasma enhanced chemical vapour deposition.Carbon composite electrode prepared from a mixture of glassy and spherical carbon powder and MWCNTs had the highest sensitivity to nucleic acids.Other interesting result is the fact that we were able to distinguish signals for all bases using this electrode.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microelectronics, Brno University of Technology, Technicka 10, CZ-61600 Brno, Czech Republic. hubalek@feec.vutbr.cz.

ABSTRACT
The first aim of this study was to fabricate vertically aligned multiwalled carbon nanotubes (MWCNTs). MWCNTs were successfully prepared by using plasma enhanced chemical vapour deposition. Further, three carbon composite electrodes with different content of carbon particles with various shapes and sizes were prepared and tested on measuring of nucleic acids. The dependences of adenine peak height on the concentration of nucleic acid sample were measured. Carbon composite electrode prepared from a mixture of glassy and spherical carbon powder and MWCNTs had the highest sensitivity to nucleic acids. Other interesting result is the fact that we were able to distinguish signals for all bases using this electrode.

No MeSH data available.


Related in: MedlinePlus