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The amplification effect of functionalized gold nanoparticles on the binding of anticancer drug dacarbazine to DNA and DNA bases
Applied Surface Science 255 (2008) 577–580
Contents lists available at ScienceDirect
Applied Surface Science journal homepage: www.elsevier.com/locate/apsusc
The amplification effect of functionalized gold nanoparticles on the binding of anticancer drug dacarbazine to DNA and DNA bases Qin Shen, Xuemei Wang *, Degang Fu State Key Lab of Bioelectronics (Chien-Shiung Wu Laboratory), Southeast University, Nanjing 210096, China
A R T I C L E I N F O
A B S T R A C T
Article history:
The promising application of functionalized gold nanoparticles to amplify the performance of biosensors and relevant biomolecular recognition processes has been explored in this paper. Our observations illustrate the apparent enhancement effect of the gold nanoparticles on the electrochemical response of the anticancer drug dacarbazine (DTIC) binding to DNA and DNA bases, indicating that these functionalized gold nanoparticles could readily facilitate the specific interactions between DTIC and DNA/DNA bases. This raises the potential valuable applications of these biocompatible nanoparticles in the promising biosensors and biomedical engineering. ß 2008 Elsevier B.V. All rights reserved.
Available online 27 June 2008 PACS: 82.47.Rs 82.80.Fk 81.16.Dn Keywords: Functionalized gold nanoparticles Dacarbazine Electrochemistry DNA recognition
1. Introduction The specific interaction between different kinds of anticancer drugs and DNA is an important fundamental issue in the fields of biochemistry, medicine and molecular biology. The application of nanomaterials in the biosensors and biomolecular recognition has attracted more and more attention because the assembling of nano-architectured materials on the relevant bio-target surface and interface could efficiently amplify the performance of target biorecognition processes. With unique properties such as large surface area, pore structure, embedded effect and size effect, some nanoparticles are recognized to have potential applications in bioelectronics and optics, genomics, proteomics, and other biomedical and bioengineering areas [1–3]. As a typical biocompatible nanomaterial, gold nanoparticles have attracted continuing and intensive research focus and have been widely used in biomedical engineering and other biological processes including biomedical imaging and biosensors [4–6]. Some biological applications of gold nanoparticles have focused on their use as probes for the detection of oligonucleotides [7–9]. The discovery that the particles bound protein without altering their
* Corresponding author. Tel.: +86 25 83792177; fax: +86 25 83792177. E-mail address: [email protected] (X. Wang). 0169-4332/$ – see front matter ß 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2008.06.132
activity paved the way for their use in hand-held immunodiagnostics and in histopathology [10]. More recently gold nanoparticles have been assembled into scaffolds for use in deoxyribonucleic acid (DNA) diagnostics [11–13]. Dacarbazine [5-(3, 3-dimethy-1-triazenyl) imidazole-4-carboxamide; DTIC] is a commonly used anticancer drug. The electrochemical properties and the DNA binding behavior of DTIC have been investigated in previous reports [14,15]. On the basis of these observations, in this study, the performance of relevant electrochemical biosensors based on some functionalized gold nanoparticles has been explored and further applied to amplify the biorecognition of the anticancer drug dacarbazine (DTIC) to DNA/ DNA bases. Our studies indicate that the functionalized gold nanoparticles could efficiently enhance the amplification performance of the related biorecognition and facilitate the specific interaction between DTIC and DNA/DNA bases. 2. Experimental 2.1. Regents All reagents used were of analytical grade. Adenine (A), Thymine (T), Guanine (G), Cytosine (C), CT-DNA were purchased from Sigma Co., while DTIC was obtained from Nanjing pharmacy factory (analytical grade). DTIC stock solutions were freshly
578
Q. Shen et al. / Applied Surface Science 255 (2008) 577–580
prepared and stored in the dark at 4 8C. Cell and voltammetric flasks were protected from light by means of aluminum foil to avoid DTIC photodecomposition. Buffer solutions were prepared in phosphate buffered saline (PBS, 0.1 M, pH 7.2) with ultrapure water (Milli-Q). Gold nanoparticles (AuNPs) used in this study were initially functionalized with 3-mercaptopropionic acid, as the thiol groups react to form covalent bonds with the Au surface. Then the functionalized AuNPs were prepared by the ligand exchange reaction between triphenyl phosphide (PPh3)-stabilized precursor nanoparticles and mercaptopropionic acid (MPA), which is similar to the previous report [16]. TEM characterization of the functionalized gold nanoparticles indicates an average diameter of 5 nm. 2.2. Electrochemical study Cyclic voltammetric (CV) studies were performed on CHI660b electrochemical workstation to detect the electrochemical behavior of DTIC. All measurements were carried out in phosphate buffered saline (PBS, 0.1 M, pH 7.2) at ambient temperature (20 2 8C) in a three-component electrochemical cell consisting of glassy carbon electrode (GCE) as the working electrode, a saturated calomel electrode as the reference electrode and a Pt electrode as the counter electrode. 3. Results and discussion 3.1. Electrochemical study on the amplified biorecognition of DTIC based on functionalized gold nanoparticles As described previously, the functionalized gold nanoparticles were initially prepared and then applied to amplify the performance of the biomolecular recognition process. The relevant biorecognition of DTIC based on functionalized gold nanoparticles has been explored by the electrochemical study in this work. Fig. 1 shows typical CV curves of DTIC in the absence and presence of functionalized gold nanoparticles. It is noted that considerable enhancement of the electrochemical response of DTIC has been observed in the presence of the functionalized gold nanoparticles. Scheme 1 illustrates the possible process for the amplified biorecognition of DTIC based on the functionalized
Fig. 1. CV study of DTIC (2.7 10 6 M) in the absence (a) and presence of different concentration of functionalized gold nanoparticles. (b) 2.0 10 9 M; (c) 4.0 10 9 M. Scan rate: 100 mV/s. Inset: Plot of the relationship between the peak current of DTIC (2.7 10 6 M) and the different concentrations of functionalized gold nanoparticles in PBS (0.1 M, pH 7.2).
Scheme 1. Scheme of the electrochemical detection of the amplified biorecognition of DTIC based on the functionalized gold nanoparticles.
gold nanoparticles. The rationale behind this is that these functionalized gold nanoparticles were stabilized by PPh3 with negative charge, while the oxidized DTIC is positively charged due to the existence of amide on the DTIC [17]. Thus, DTIC could be easily self-assembled onto the surface of functionalized gold nanoparticles through electrostatic interaction. That would readily lead to much more DTIC molecules approaching the surface of the glassy carbon electrode upon application of the external redox potentials. The inset in Fig. 1 illustrates the relationship between peak current of DTIC and concentration of functionalized gold nanoparticles. With the concentration of gold nanoparticles up to 3.0 10 9 M, the peak current of the electrochemical response of DTIC does not increase any more. So the concentration of 3.0 10 9 M is adopted in the following studies. 3.2. Influence of functionalized gold nanoparticles on the interaction of DTIC with DNA/DNA bases Based on the studies above, the performance of the relevant electrochemical biosensors based on some functionalized gold nanoparticles has been further applied to amplify the biorecognition of the anticancer drug DTIC for DNA/DNA bases. As shown in
Fig. 2. CV study of DTIC (2.7 10 6 M) binding to Adenine (A) (8.2 10 5 M) in the absence (b and c) and presence (a and d) of functionalized gold nanoparticles (3.0 10 9 M). (a) DTIC in the presence of gold nanoparticles, (b) DTIC alone, (c) DTIC and A, (d) DTIC and A in the presence of gold nanoparticles. Scan rate: 100 mV/s.
Q. Shen et al. / Applied Surface Science 255 (2008) 577–580
579
Fig. 3. CV study of DTIC (2.7 10 6 M) binding to Guanine (G) (8.2 10 5 M) in the absence (b and c) and presence (a and d) of functionalized gold nanoparticles (3.0 10 9 M). (a) DTIC in the presence of gold nanoparticles, (b) DTIC alone, (c) DTIC and G, and (d) DTIC and G in the presence of gold nanoparticles. Scan rate: 100 mV/s.
Fig. 4. CV study of DTIC (2.7 10 6 M) binding to DNA (2.0 10 5 M) in the absence (b and c) and presence (a and d) of functionalized gold nanoparticles (3.0 10 9 M). (a) DTIC in the presence of gold nanoparticles, (b) DTIC alone, (c) DTIC and DNA, and (d) DTIC and DNA in the presence of gold nanoparticles. Scan rate: 100 mV/s.
the following electrochemical study, our observations indicate that the presence of these gold nanoparticles can obviously increase the binding affinity of DTIC to DNA or DNA bases, thus a much bigger decrease of the peak current of the electrochemical response of DTIC was observed than that in the absence of gold nanoparticles under the identical experimental conditions. Fig. 2 illustrates the typical CV study of DTIC binding to adenine (A) in the absence and presence of relevant gold nanoparticles. It is noted that a remarkable enhancement effect on the binding affinity of DTIC to base A appears in the presence of these nanoparticles. More significant change of peak current is observed upon addition of functionalized gold nanoparticles. The electrochemical behavior of DTIC binding to other DNA bases has been also explored and the similar remarkable enhancement effect also was found for base guanine (G) and thymine (T) (as shown in Table A.1 in Appendix A). Fig. 3 shows a typical example of the CV study of DTIC binding to base guanine (G), which demonstrates the considerable enhancement of the binding affinity in the presence of functionalized gold nanoparticles under identical experimental conditions. However, the presence of gold nanoparticles has less effect on the interaction of DTIC with cytosine (C). It is noted that in the absence of gold nanoparticles, the DTIC peak current decreased by 29.2% when binding to base C, while in the presence of functionalized gold nanoparticles, the decrease of its peak current is 36.5% under the identical experimental conditions. Meanwhile, the efficient amplification performance of the relevant electrochemical biorecognition of DNA based on functionalized gold nanoparticles has been consistently observed in our studies. Fig. 4 shows typical CV curves of DTIC binding to DNA, which demonstrates that considerable decrease of the peak current of the electrochemical response occurs in the presence of functionalized gold nanoparticles. Therefore, based on the above
observations, our studies indicate that the functionalized gold nanoparticles could efficiently enhance the related biorecognition and facilitate the specific interaction between DTIC and DNA/DNA bases. The different binding behavior of DTIC in the presence of different DNA/DNA bases may be attributed to the specific orientation or interaction of the relevant biomolecules on the surface of functionalized gold nanoparticles, and the assembling of the respective biomolecules on the nano-architectured surface or interface could efficiently amplify the performance of target biorecognition process, which could thus remarkably facilitate the binding of DTIC to DNA or DNA bases. 4. Conclusions In summary, functionalized gold nanoparticles were prepared and utilized to facilitate the specific interactions between anticancer drug DTIC and DNA or DNA bases. The results indicate that the assembling of biomolecules on the nanoarchitectured particles could efficiently amplify the performance of electrochemical biosensors and target biorecognition process and thus the relevant gold nanoparticles could be used as a nice nano-interface to enhance the detection sensitivity for biomolecular recognition of some antitumor drugs like DTIC. This may raise the potential valuable applications of these gold nanoparticles in the relative biomedical and bioengineering areas. Acknowledgements This work was supported by NSFC (20675014, 90713023) and Ministry of Science & Technology of China (2007AA022007).
Appendix A
Table A.1 The amplification effect of functionalized gold nanoparticles on the binding behavior of DTIC (2.7 10
6
M) to different DNA bases
DTIC peak current variety/percentage
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
Without gold nanoparticles With gold nanoparticles (3.0 10
34.7 50.1
14.7 41.1
29.2 36.5
19.4 41.7
9
M)
580
Q. Shen et al. / Applied Surface Science 255 (2008) 577–580
References [1] S. Park, A.A. Lazarides, C.A. Mirkin, Angew. Chem. 112 (2000) 4003. [2] T. You, O. Niwa, M. Tomita, S. Hirono, Anal. Chem. 75 (2003) 2080. [3] X.X. He, K. Wang, W.H. Tan, B. Liu, X. Lin, C.M. He, D. Li, S.S. Huang, J. Li, J. Am. Chem. Soc. 125 (2003) 7168. [4] M.C. Daniel, D. Astruc, Chem. Rev. 104 (2004) 293. [5] T.A. Taton, C.A. Mirkin, R.L. Letsinger, Science 289 (2000) 1757. [6] W. Joseph, P. Ronen, X. Danke, Langmuir 17 (2001) 5739. [7] A.B. Steel, T.M. Herne, M.J. Tarlov, Anal. Chem. 70 (1998) 4670. [8] H. Lin, D.M. Micheal, R.N. Sheila, J. Am Chem. Soc. 122 (2000) 9071.
[9] [10] [11] [12] [13] [14] [15] [16] [17]
H. Cai, Y.Q. Wang, Y.Z. Fang, Anal. Chim. Acta 469 (2002) 165. F. Paciotti, G.I. Kingston, Lawrence Tamarkin, Drug Dev. Res. 67 (2006) 47. T.C. Shad, D.G. Georganopoulou, C.A. Mirkin, Clin. Chim. Acta 363 (2006) 120. J.J. Storhoff, S.S. Marla, P. Bao, Biosens. Bioelectron. 19 (2004) 875. Y.P. Bao, M. Huber, T.F. Wei, S.S. Marla, J.J. Storhoff, U.R. Muller, Nucl. Acids Res. 33 (2005) e15. M. Song, R.Y. Zhang, X.M. Wang, Mater. Lett. 60 (2006) 2143. R.Y. Zhang, X.M. Wang, S.J. Gong, Electrochem. Solid State Lett. 7 (2004) J27. G.H. Woehrle, L.O. Brown, J.E. Hutchison, J. Am. Chem. Soc. 127 (2005) 2172. A.J. Miranda Ordieres, A. Costa Garcia, P. Tunon Blanco, Anal. Chim. Acta 202 (1987) 141.
Contents lists available at ScienceDirect
Applied Surface Science journal homepage: www.elsevier.com/locate/apsusc
The amplification effect of functionalized gold nanoparticles on the binding of anticancer drug dacarbazine to DNA and DNA bases Qin Shen, Xuemei Wang *, Degang Fu State Key Lab of Bioelectronics (Chien-Shiung Wu Laboratory), Southeast University, Nanjing 210096, China
A R T I C L E I N F O
A B S T R A C T
Article history:
The promising application of functionalized gold nanoparticles to amplify the performance of biosensors and relevant biomolecular recognition processes has been explored in this paper. Our observations illustrate the apparent enhancement effect of the gold nanoparticles on the electrochemical response of the anticancer drug dacarbazine (DTIC) binding to DNA and DNA bases, indicating that these functionalized gold nanoparticles could readily facilitate the specific interactions between DTIC and DNA/DNA bases. This raises the potential valuable applications of these biocompatible nanoparticles in the promising biosensors and biomedical engineering. ß 2008 Elsevier B.V. All rights reserved.
Available online 27 June 2008 PACS: 82.47.Rs 82.80.Fk 81.16.Dn Keywords: Functionalized gold nanoparticles Dacarbazine Electrochemistry DNA recognition
1. Introduction The specific interaction between different kinds of anticancer drugs and DNA is an important fundamental issue in the fields of biochemistry, medicine and molecular biology. The application of nanomaterials in the biosensors and biomolecular recognition has attracted more and more attention because the assembling of nano-architectured materials on the relevant bio-target surface and interface could efficiently amplify the performance of target biorecognition processes. With unique properties such as large surface area, pore structure, embedded effect and size effect, some nanoparticles are recognized to have potential applications in bioelectronics and optics, genomics, proteomics, and other biomedical and bioengineering areas [1–3]. As a typical biocompatible nanomaterial, gold nanoparticles have attracted continuing and intensive research focus and have been widely used in biomedical engineering and other biological processes including biomedical imaging and biosensors [4–6]. Some biological applications of gold nanoparticles have focused on their use as probes for the detection of oligonucleotides [7–9]. The discovery that the particles bound protein without altering their
* Corresponding author. Tel.: +86 25 83792177; fax: +86 25 83792177. E-mail address: [email protected] (X. Wang). 0169-4332/$ – see front matter ß 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2008.06.132
activity paved the way for their use in hand-held immunodiagnostics and in histopathology [10]. More recently gold nanoparticles have been assembled into scaffolds for use in deoxyribonucleic acid (DNA) diagnostics [11–13]. Dacarbazine [5-(3, 3-dimethy-1-triazenyl) imidazole-4-carboxamide; DTIC] is a commonly used anticancer drug. The electrochemical properties and the DNA binding behavior of DTIC have been investigated in previous reports [14,15]. On the basis of these observations, in this study, the performance of relevant electrochemical biosensors based on some functionalized gold nanoparticles has been explored and further applied to amplify the biorecognition of the anticancer drug dacarbazine (DTIC) to DNA/ DNA bases. Our studies indicate that the functionalized gold nanoparticles could efficiently enhance the amplification performance of the related biorecognition and facilitate the specific interaction between DTIC and DNA/DNA bases. 2. Experimental 2.1. Regents All reagents used were of analytical grade. Adenine (A), Thymine (T), Guanine (G), Cytosine (C), CT-DNA were purchased from Sigma Co., while DTIC was obtained from Nanjing pharmacy factory (analytical grade). DTIC stock solutions were freshly
578
Q. Shen et al. / Applied Surface Science 255 (2008) 577–580
prepared and stored in the dark at 4 8C. Cell and voltammetric flasks were protected from light by means of aluminum foil to avoid DTIC photodecomposition. Buffer solutions were prepared in phosphate buffered saline (PBS, 0.1 M, pH 7.2) with ultrapure water (Milli-Q). Gold nanoparticles (AuNPs) used in this study were initially functionalized with 3-mercaptopropionic acid, as the thiol groups react to form covalent bonds with the Au surface. Then the functionalized AuNPs were prepared by the ligand exchange reaction between triphenyl phosphide (PPh3)-stabilized precursor nanoparticles and mercaptopropionic acid (MPA), which is similar to the previous report [16]. TEM characterization of the functionalized gold nanoparticles indicates an average diameter of 5 nm. 2.2. Electrochemical study Cyclic voltammetric (CV) studies were performed on CHI660b electrochemical workstation to detect the electrochemical behavior of DTIC. All measurements were carried out in phosphate buffered saline (PBS, 0.1 M, pH 7.2) at ambient temperature (20 2 8C) in a three-component electrochemical cell consisting of glassy carbon electrode (GCE) as the working electrode, a saturated calomel electrode as the reference electrode and a Pt electrode as the counter electrode. 3. Results and discussion 3.1. Electrochemical study on the amplified biorecognition of DTIC based on functionalized gold nanoparticles As described previously, the functionalized gold nanoparticles were initially prepared and then applied to amplify the performance of the biomolecular recognition process. The relevant biorecognition of DTIC based on functionalized gold nanoparticles has been explored by the electrochemical study in this work. Fig. 1 shows typical CV curves of DTIC in the absence and presence of functionalized gold nanoparticles. It is noted that considerable enhancement of the electrochemical response of DTIC has been observed in the presence of the functionalized gold nanoparticles. Scheme 1 illustrates the possible process for the amplified biorecognition of DTIC based on the functionalized
Fig. 1. CV study of DTIC (2.7 10 6 M) in the absence (a) and presence of different concentration of functionalized gold nanoparticles. (b) 2.0 10 9 M; (c) 4.0 10 9 M. Scan rate: 100 mV/s. Inset: Plot of the relationship between the peak current of DTIC (2.7 10 6 M) and the different concentrations of functionalized gold nanoparticles in PBS (0.1 M, pH 7.2).
Scheme 1. Scheme of the electrochemical detection of the amplified biorecognition of DTIC based on the functionalized gold nanoparticles.
gold nanoparticles. The rationale behind this is that these functionalized gold nanoparticles were stabilized by PPh3 with negative charge, while the oxidized DTIC is positively charged due to the existence of amide on the DTIC [17]. Thus, DTIC could be easily self-assembled onto the surface of functionalized gold nanoparticles through electrostatic interaction. That would readily lead to much more DTIC molecules approaching the surface of the glassy carbon electrode upon application of the external redox potentials. The inset in Fig. 1 illustrates the relationship between peak current of DTIC and concentration of functionalized gold nanoparticles. With the concentration of gold nanoparticles up to 3.0 10 9 M, the peak current of the electrochemical response of DTIC does not increase any more. So the concentration of 3.0 10 9 M is adopted in the following studies. 3.2. Influence of functionalized gold nanoparticles on the interaction of DTIC with DNA/DNA bases Based on the studies above, the performance of the relevant electrochemical biosensors based on some functionalized gold nanoparticles has been further applied to amplify the biorecognition of the anticancer drug DTIC for DNA/DNA bases. As shown in
Fig. 2. CV study of DTIC (2.7 10 6 M) binding to Adenine (A) (8.2 10 5 M) in the absence (b and c) and presence (a and d) of functionalized gold nanoparticles (3.0 10 9 M). (a) DTIC in the presence of gold nanoparticles, (b) DTIC alone, (c) DTIC and A, (d) DTIC and A in the presence of gold nanoparticles. Scan rate: 100 mV/s.
Q. Shen et al. / Applied Surface Science 255 (2008) 577–580
579
Fig. 3. CV study of DTIC (2.7 10 6 M) binding to Guanine (G) (8.2 10 5 M) in the absence (b and c) and presence (a and d) of functionalized gold nanoparticles (3.0 10 9 M). (a) DTIC in the presence of gold nanoparticles, (b) DTIC alone, (c) DTIC and G, and (d) DTIC and G in the presence of gold nanoparticles. Scan rate: 100 mV/s.
Fig. 4. CV study of DTIC (2.7 10 6 M) binding to DNA (2.0 10 5 M) in the absence (b and c) and presence (a and d) of functionalized gold nanoparticles (3.0 10 9 M). (a) DTIC in the presence of gold nanoparticles, (b) DTIC alone, (c) DTIC and DNA, and (d) DTIC and DNA in the presence of gold nanoparticles. Scan rate: 100 mV/s.
the following electrochemical study, our observations indicate that the presence of these gold nanoparticles can obviously increase the binding affinity of DTIC to DNA or DNA bases, thus a much bigger decrease of the peak current of the electrochemical response of DTIC was observed than that in the absence of gold nanoparticles under the identical experimental conditions. Fig. 2 illustrates the typical CV study of DTIC binding to adenine (A) in the absence and presence of relevant gold nanoparticles. It is noted that a remarkable enhancement effect on the binding affinity of DTIC to base A appears in the presence of these nanoparticles. More significant change of peak current is observed upon addition of functionalized gold nanoparticles. The electrochemical behavior of DTIC binding to other DNA bases has been also explored and the similar remarkable enhancement effect also was found for base guanine (G) and thymine (T) (as shown in Table A.1 in Appendix A). Fig. 3 shows a typical example of the CV study of DTIC binding to base guanine (G), which demonstrates the considerable enhancement of the binding affinity in the presence of functionalized gold nanoparticles under identical experimental conditions. However, the presence of gold nanoparticles has less effect on the interaction of DTIC with cytosine (C). It is noted that in the absence of gold nanoparticles, the DTIC peak current decreased by 29.2% when binding to base C, while in the presence of functionalized gold nanoparticles, the decrease of its peak current is 36.5% under the identical experimental conditions. Meanwhile, the efficient amplification performance of the relevant electrochemical biorecognition of DNA based on functionalized gold nanoparticles has been consistently observed in our studies. Fig. 4 shows typical CV curves of DTIC binding to DNA, which demonstrates that considerable decrease of the peak current of the electrochemical response occurs in the presence of functionalized gold nanoparticles. Therefore, based on the above
observations, our studies indicate that the functionalized gold nanoparticles could efficiently enhance the related biorecognition and facilitate the specific interaction between DTIC and DNA/DNA bases. The different binding behavior of DTIC in the presence of different DNA/DNA bases may be attributed to the specific orientation or interaction of the relevant biomolecules on the surface of functionalized gold nanoparticles, and the assembling of the respective biomolecules on the nano-architectured surface or interface could efficiently amplify the performance of target biorecognition process, which could thus remarkably facilitate the binding of DTIC to DNA or DNA bases. 4. Conclusions In summary, functionalized gold nanoparticles were prepared and utilized to facilitate the specific interactions between anticancer drug DTIC and DNA or DNA bases. The results indicate that the assembling of biomolecules on the nanoarchitectured particles could efficiently amplify the performance of electrochemical biosensors and target biorecognition process and thus the relevant gold nanoparticles could be used as a nice nano-interface to enhance the detection sensitivity for biomolecular recognition of some antitumor drugs like DTIC. This may raise the potential valuable applications of these gold nanoparticles in the relative biomedical and bioengineering areas. Acknowledgements This work was supported by NSFC (20675014, 90713023) and Ministry of Science & Technology of China (2007AA022007).
Appendix A
Table A.1 The amplification effect of functionalized gold nanoparticles on the binding behavior of DTIC (2.7 10
6
M) to different DNA bases
DTIC peak current variety/percentage
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
Without gold nanoparticles With gold nanoparticles (3.0 10
34.7 50.1
14.7 41.1
29.2 36.5
19.4 41.7
9
M)
580
Q. Shen et al. / Applied Surface Science 255 (2008) 577–580
References [1] S. Park, A.A. Lazarides, C.A. Mirkin, Angew. Chem. 112 (2000) 4003. [2] T. You, O. Niwa, M. Tomita, S. Hirono, Anal. Chem. 75 (2003) 2080. [3] X.X. He, K. Wang, W.H. Tan, B. Liu, X. Lin, C.M. He, D. Li, S.S. Huang, J. Li, J. Am. Chem. Soc. 125 (2003) 7168. [4] M.C. Daniel, D. Astruc, Chem. Rev. 104 (2004) 293. [5] T.A. Taton, C.A. Mirkin, R.L. Letsinger, Science 289 (2000) 1757. [6] W. Joseph, P. Ronen, X. Danke, Langmuir 17 (2001) 5739. [7] A.B. Steel, T.M. Herne, M.J. Tarlov, Anal. Chem. 70 (1998) 4670. [8] H. Lin, D.M. Micheal, R.N. Sheila, J. Am Chem. Soc. 122 (2000) 9071.
[9] [10] [11] [12] [13] [14] [15] [16] [17]
H. Cai, Y.Q. Wang, Y.Z. Fang, Anal. Chim. Acta 469 (2002) 165. F. Paciotti, G.I. Kingston, Lawrence Tamarkin, Drug Dev. Res. 67 (2006) 47. T.C. Shad, D.G. Georganopoulou, C.A. Mirkin, Clin. Chim. Acta 363 (2006) 120. J.J. Storhoff, S.S. Marla, P. Bao, Biosens. Bioelectron. 19 (2004) 875. Y.P. Bao, M. Huber, T.F. Wei, S.S. Marla, J.J. Storhoff, U.R. Muller, Nucl. Acids Res. 33 (2005) e15. M. Song, R.Y. Zhang, X.M. Wang, Mater. Lett. 60 (2006) 2143. R.Y. Zhang, X.M. Wang, S.J. Gong, Electrochem. Solid State Lett. 7 (2004) J27. G.H. Woehrle, L.O. Brown, J.E. Hutchison, J. Am. Chem. Soc. 127 (2005) 2172. A.J. Miranda Ordieres, A. Costa Garcia, P. Tunon Blanco, Anal. Chim. Acta 202 (1987) 141.