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Nanomedicine: Nanotechnology, Biology, and Medicine xx (2015) xxx – xxx nanomedjournal.com
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Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection Hsin-Neng Wang, PhD a, b , Andrew M. Fales, BS a, b , Tuan Vo-Dinh, PhD a, b, c,⁎
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Department of Biomedical Engineering, Duke University, Durham, NC, USA b Fitzpatrick Institute for Photonics, Duke University, Durham, NC, USA c Department of Chemistry, Duke University, Durham, NC, USA Received 9 July 2014; accepted 17 December 2014
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Abstract
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Developing a simple and efficient nucleic acid detection technology is essential for clinical diagnostics. Here, we describe a new conceptually simple and selective “turn on” plasmonics-based nanobiosensor, which integrates non-enzymatic DNA strand-displacement hybridization for specific nucleic acid target identification with surface-enhanced Raman scattering (SERS) detection. This SERS nanobiosensor is a target label-free, and rapid nanoparticle-based biosensing system using a homogeneous assay format that offers a simple and efficient tool for nucleic acid diagnostics. Our results showed that the nanobiosensor provided a limit of detection of ~ 0.1 nM (200 amol) in the current bioassay system, and exhibited high specificity for single nucleotide mismatch discrimination. © 2015 Published by Elsevier Inc.
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Key words: Surface-enhanced Raman scattering (SERS); Nanobiosensor; Nucleic acid detection
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Background
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The detection of nucleic acids is critical for many applications ranging from medical diagnostics, environmental and food safety monitoring, to homeland security. For medical applications, nucleic acid biomarkers, such as DNA, mRNA and microRNA, have long been considered as valuable diagnostic indicators to monitor the presence and progression of various diseases. Therefore, much effort has been devoted to develop sensitive, selective and practical methods for detection of nucleic acid biomarkers. With recent advances in nanotechnology, various approaches have been developed to detect nucleic acids using plasmonics-active metallic (e.g. silver and gold) nanoparticles or nanostructured substrates for surface-enhanced Raman scattering
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The authors report no conflict of interest. This work was sponsored by the Defense Advanced Research Projects Agency (HR0011-13-2-0003) and the Duke University Exploratory Research Funds. The content of this article does not necessarily reflect the position of the policy of the Government, and no official endorsement should be inferred. ⁎Corresponding author at: Department of Biomedical Engineering, Duke University, Durham, NC, USA. E-mail address: [email protected] (T. Vo-Dinh).
(SERS) detection. 1-7 However, to generate a strong SERS signal or to identify specific target sequences, many of existing methods require either multiple incubation/washing steps or target labeling, thus increasing the assay complexity. Over the past years, we have developed a variety of SERS plasmonic platforms for chemical and biological sensing. 8-11 In this work, we describe a new plasmonics-based homogeneous nanobiosensor with “OFF-to-ON” SERS signal switch upon nucleic acid target identification and capture (Figure 1, A). We first implemented the SERS nanobiosensor using silver-coated gold nanostars (AuNS@Ag) as the SERS-active platforms (Figure 1, B). 12,13 AuNS@Ag is a new hybrid bimetallic nanostar-based platform that exhibits superior resonant SERS properties. We have recently demonstrated that AuNS@Ag provides over an order of magnitude of signal enhancement compared to uncoated gold nanostrars (AuNS). 13 As shown in Figure 1, A, the “stem-loop” DNA probe, having a Raman label at one end, is immobilized onto a nanostar via a metal-thiol bond. A single-stranded DNA serving as a “placeholder” strand is partially hybridized to the stem-loop probe via a placeholder-binding region, keeping the label away from the nanostar surface. In this configuration (i.e. in the absence of a target), the probe is “open” with low SERS intensity (‘Off’ status) as the plasmon field enhancement decreases
http://dx.doi.org/10.1016/j.nano.2014.12.012 1549-9634/© 2015 Published by Elsevier Inc. Please cite this article as: Wang H.-N., et al., Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection. Nanomedicine: NBM 2015;xx:1-4, http://dx.doi.org/10.1016/j.nano.2014.12.012
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Figure 2. (A) SERS spectra of the nanobiosensor in the presence or absence of target DNA. (B) Evaluation of the response time of the nanobiosensor.
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significantly with increasing distance from the surface. Upon exposure to a target sequence, the placeholder strand leaves the nanostar surface following a non-enzymatic strand-displacement process 14,15: the target first binds to the toehold region (i.e. an overhang region of the probe-placeholder conjugate) (Intermediate I) and begins displacing the DNA probe from the placeholder via branch migration (Intermediate II), and finally releases the placeholder from the nanoparticle system. This allows the stem-loop structure to “close” and moves the Raman label onto the plasmonics-active surface of the nanostar yielding a strong SERS signal (‘On’ status).
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As a proof of concept, the human radical S-adenosyl methionine domain containing 2 (RSAD2) gene, known to be a host-response biomarker for infections diseases, 16,17 was used as the model system to demonstrate feasibility of this SERS nanobiosensor. In this study, the AuNS seeds and AuNS@Ag
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The feasibility of using the SERS nanobiosensor for nucleic acid detection is demonstrated in Figure 2, A. In the presence of 1 μM target DNA (curve c), the SERS intensity was significantly increased indicating that the hybridization between targets and placeholders enabled the formation of the stem-loop structure of the nanobiosensor, thereby moving the SERS dye onto the nanostar surface and turning the SERS signal “On”. The success of the detection using the nanobiosensor was further confirmed by an alternative fluorescence quenching and recovery experiment (Figure S1). To evaluate the effective reaction time of the nanobiosensor, the “Off” nanobiosensor was incubated with 1 μM complementary targets at 37 °C in PBS followed by the SERS measurements at different time points. Figure 2, B shows that the nanobiosensor can be effectively turned on in 10 min, and the signal was further slightly increased by extending the reaction time to 1 h.
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Figure 1. (A) Detection scheme of the SERS nanobiosensor. (B) TEM images of the synthesized AuNS seeds and AuNS@Ag.
were prepared according to our previous reports. 12,13 Further details regarding DNA probe sequences, nanobiosensor synthesis and assay procedure can be found in the Supplementary Materials.
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Discussion
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The novel nanobiosensor developed in this study provides a simple and efficient nucleic acid assay system. As a proof of concept, we first designed the placeholder with a moderate, 8-base toehold containing equal numbers of G/C and A/T bases. According to a previous study, 18 the kinetics of strand displacement can be modulated by changing the length or the sequence composition (i.e. G/C content) of toeholds. Thus, the effective reaction time for turning on the SERS signal will depend on the toeholds used, e.g. using a strong toehold with a higher G/C content would result in a faster reaction rate. For quantitative analysis, a logarithmic fit to the data was obtained. With over 50 nM of target DNA, the SERS signal is expected to reach a plateau. However, as shown in the inset of Figure 3, a linear trend line was fitted to the data between 0 to 5 nM with a slope (s = 376.47) and a residual standard deviation (σ = 28.87). The limit of detection (LOD) (3σ/s) for target DNA
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The possibility for quantitative analysis was demonstrated by using a small sample volume (2 μL). Figure 3 illustrates that the SERS intensity at the 557 cm − 1 Raman peak increases with increasing the amount of target DNA confirming that more Raman labels were being moved close to the nanostar surface. We next evaluated the detection specificity using the perfectly matched target and sequences having one, two or three-base mismatches. Figure 4, A shows that the SERS intensity at 557 cm − 1 decreases with increasing numbers of mismatched bases. In the case of one-base mismatch, the SERS intensity is about 30% less than the perfectly matched target. To further demonstrate the capability of our system to discriminate single nucleotide differences, the nanobiosensor was tested in solutions with different ionic strength at 37 °C for 1 h. As shown in Figure 4, B, the SERS signal of the nanobiosensor treated with one-base mismatched sequences decreases with decreasing the NaCl concentration in the reaction buffer.
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Figure 3. Evaluation of the detection sensitivity of the nanobiosensor.
Figure 4. (A) Evaluation of the detection specificity of the nanobiosensor. (B) Evaluation of the single-mismatch discrimination in solutions with different ionic strength.
was determined to be ~ 0.1 nM in the current bioassay system. It is noteworthy that our analysis used very small amounts of samples (2 μL). As a result, the absolute LOD is only 200 amol. The specificity of detection is critical for many clinical applications, such as single-nucleotide polymorphism (SNP) identification or microRNA detection. It was found that reducing the ionic strength of the media could further improve the detection specificity. This is due to the fact that the mismatched target-placeholder duplex (i.e. Intermediate II) is thermodynamically unstable in low ionic strength solutions compared to the perfectly matched duplex (Table S1). Note that during the experimental process, we did not observe the aggregation of the PEG-stabilized nanobiosensor when changing the salt concentration of the buffer (Figure S2). Moreover, the reported nanobiosensor showed an excellent reproducibility with an average relative standard deviation (RSD) less than 5%. In conclusion, we have demonstrated, for the first time, the proof of concept of using the novel “OFF-to-ON” SERS nanobiosensor to detect nucleic acid targets. The nanobiosensor is a target label-free homogeneous assay as it does not require labeling targets and post-hybridization washing steps, making the procedure simple and rapid.
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Appendix A. Supplementary data
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Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.nano.2014.12.012.
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References
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1. Cao YC, Jin R, Mirkin CA. Nanoparticles with Raman spectroscopic fingerprints for DNA and RNA detection. Science 2002;297(5586):1536-40. 2. Fabris L, Dante M, Braun G, Lee SJ, Reich NO, Moskovits M, et al. A heterogeneous PNA-based SERS method for DNA detection. J Am Chem Soc 2007;129(19):6086-7. 3. Faulds K, Jarvis R, Smith WE, Graham D, Goodacre R. Multiplexed detection of six labelled oligonucleotides using surface enhanced resonance Raman scattering (SERRS). Analyst 2008;133(11):1505-12. 4. Kang T, Yoo SM, Yoon I, Lee SY, Kim B. Patterned multiplex pathogen DNA detection by Au particle-on-wire SERS sensor. Nano Lett 2010;10(4):1189-93. 5. Dougan JA, MacRae D, Graham D, Faulds K. DNA detection using enzymatic signal production and SERS. Chem Commun 2011;47(16):4649-51. 6. Li JM, Wei C, Ma WF, An Q, Guo J, Hu J, et al. Multiplexed SERS detection of DNA targets in a sandwich-hybridization assay using SERSencoded core–shell nanospheres. J Mater Chem 2012;22(24):12100-6. 7. Bantz KC, Meyer AF, Wittenberg NJ, Im H, Kurtuluş Ö, Lee SH, et al. Recent progress in SERS biosensing. Phys Chem Chem Phys 2011;13(24):11551-67.
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8. Vo-Dinh T, Yan F, Wabuyele MB. Surface-enhanced Raman scattering for medical diagnostics and biological imaging. J Raman Spectrosc 2005;36(6-7):640-7. 9. Wang HN, Vo-Dinh T. Multiplex detection of breast cancer biomarkers using plasmonic molecular sentinel nanoprobes. Nanotechnology 2009;20(6):065101. 10. Vo-Dinh T, Dhawan A, Norton SJ, Khoury CG, Wang HN, Misra V, et al. Plasmonic nanoparticles and nanowires: design, fabrication and application in sensing. J Phys Chem C 2010;114(16):7480-8. 11. Wang HN, Vo-Dinh T. Plasmonic coupling interference (PCI) nanoprobes for nucleic acid detection. Small 2011;7(21):3067-74. 12. Fales AM, Yuan H, Vo-Dinh T. Silica-coated gold nanostars for combined surface-enhanced Raman scattering (SERS) detection and singlet-oxygen generation: a potential nanoplatform for theranostics. Langmuir 2011;27(19):12186-90. 13. Fales AM, Yuan H, Vo-Dinh T. Development of hybrid silver-coated gold nanostars for nonaggregated surface-enhanced Raman scattering. J Phys Chem C 2014;118(7):3708-15. 14. Bath J, Turberfield AJ. DNA nanomachines. Nat Nanotechnol 2007;2(5):275-84. 15. Zhang DY, Seelig G. Dynamic DNA nanotechnology using stranddisplacement reactions. Nat Chem 2011;3(2):103-13. 16. Zaas AK, Chen M, Varkey J, Veldman T, Hero III AO, Lucas J, et al. Gene expression signatures diagnose influenza and other symptomatic respiratory viral infections in humans. Cell Host Microbe 2009;6(3):207-17. 17. Zaas AK, Burke T, Chen M, McClain M, Nicholson B, Veldman T, et al. A host-based RT-PCR gene expression signature to identify acute respiratory viral infection. Sci Transl Med 2013;5(203):203ra126. 18. Zhang DY, Winfree E. Control of DNA strand displacement kinetics using toehold exchange. J Am Chem Soc 2009;131(47):17303-14.
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Nanomedicine: Nanotechnology, Biology, and Medicine xx (2015) xxx – xxx nanomedjournal.com
Graphical Abstract
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Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection
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Hsin-Neng Wang, PhD a,b, Andrew M. Fales, BS a,b, Tuan Vo-Dinh, PhD a,b,c,⁎
Nanomedicine: Nanotechnology, Biology, and Medicine xxx (2015) xxx – xxx
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Department of Biomedical Engineering, Duke University, Durham, NC, USA Fitzpatrick Institute for Photonics, Duke University, Durham, NC, USA Department of Chemistry, Duke University, Durham, NC, USA
A new “turn on” plasmonics-based nanobiosensor for nucleic acid detection has been developed. This nanobiosensor integrating non-enzymatic DNA strand-displacement hybridization for specific target identification with surface-enhanced Raman scattering (SERS) detection is a target label-free and homogeneous nanoparticle-based biosensing system.
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Nanomedicine: Nanotechnology, Biology, and Medicine xx (2015) xxx – xxx nanomedjournal.com
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Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection Hsin-Neng Wang, PhD a, b , Andrew M. Fales, BS a, b , Tuan Vo-Dinh, PhD a, b, c,⁎
3Q1
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Department of Biomedical Engineering, Duke University, Durham, NC, USA b Fitzpatrick Institute for Photonics, Duke University, Durham, NC, USA c Department of Chemistry, Duke University, Durham, NC, USA Received 9 July 2014; accepted 17 December 2014
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Developing a simple and efficient nucleic acid detection technology is essential for clinical diagnostics. Here, we describe a new conceptually simple and selective “turn on” plasmonics-based nanobiosensor, which integrates non-enzymatic DNA strand-displacement hybridization for specific nucleic acid target identification with surface-enhanced Raman scattering (SERS) detection. This SERS nanobiosensor is a target label-free, and rapid nanoparticle-based biosensing system using a homogeneous assay format that offers a simple and efficient tool for nucleic acid diagnostics. Our results showed that the nanobiosensor provided a limit of detection of ~ 0.1 nM (200 amol) in the current bioassay system, and exhibited high specificity for single nucleotide mismatch discrimination. © 2015 Published by Elsevier Inc.
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Key words: Surface-enhanced Raman scattering (SERS); Nanobiosensor; Nucleic acid detection
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Background
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The detection of nucleic acids is critical for many applications ranging from medical diagnostics, environmental and food safety monitoring, to homeland security. For medical applications, nucleic acid biomarkers, such as DNA, mRNA and microRNA, have long been considered as valuable diagnostic indicators to monitor the presence and progression of various diseases. Therefore, much effort has been devoted to develop sensitive, selective and practical methods for detection of nucleic acid biomarkers. With recent advances in nanotechnology, various approaches have been developed to detect nucleic acids using plasmonics-active metallic (e.g. silver and gold) nanoparticles or nanostructured substrates for surface-enhanced Raman scattering
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The authors report no conflict of interest. This work was sponsored by the Defense Advanced Research Projects Agency (HR0011-13-2-0003) and the Duke University Exploratory Research Funds. The content of this article does not necessarily reflect the position of the policy of the Government, and no official endorsement should be inferred. ⁎Corresponding author at: Department of Biomedical Engineering, Duke University, Durham, NC, USA. E-mail address: [email protected] (T. Vo-Dinh).
(SERS) detection. 1-7 However, to generate a strong SERS signal or to identify specific target sequences, many of existing methods require either multiple incubation/washing steps or target labeling, thus increasing the assay complexity. Over the past years, we have developed a variety of SERS plasmonic platforms for chemical and biological sensing. 8-11 In this work, we describe a new plasmonics-based homogeneous nanobiosensor with “OFF-to-ON” SERS signal switch upon nucleic acid target identification and capture (Figure 1, A). We first implemented the SERS nanobiosensor using silver-coated gold nanostars (AuNS@Ag) as the SERS-active platforms (Figure 1, B). 12,13 AuNS@Ag is a new hybrid bimetallic nanostar-based platform that exhibits superior resonant SERS properties. We have recently demonstrated that AuNS@Ag provides over an order of magnitude of signal enhancement compared to uncoated gold nanostrars (AuNS). 13 As shown in Figure 1, A, the “stem-loop” DNA probe, having a Raman label at one end, is immobilized onto a nanostar via a metal-thiol bond. A single-stranded DNA serving as a “placeholder” strand is partially hybridized to the stem-loop probe via a placeholder-binding region, keeping the label away from the nanostar surface. In this configuration (i.e. in the absence of a target), the probe is “open” with low SERS intensity (‘Off’ status) as the plasmon field enhancement decreases
http://dx.doi.org/10.1016/j.nano.2014.12.012 1549-9634/© 2015 Published by Elsevier Inc. Please cite this article as: Wang H.-N., et al., Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection. Nanomedicine: NBM 2015;xx:1-4, http://dx.doi.org/10.1016/j.nano.2014.12.012
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Figure 2. (A) SERS spectra of the nanobiosensor in the presence or absence of target DNA. (B) Evaluation of the response time of the nanobiosensor.
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significantly with increasing distance from the surface. Upon exposure to a target sequence, the placeholder strand leaves the nanostar surface following a non-enzymatic strand-displacement process 14,15: the target first binds to the toehold region (i.e. an overhang region of the probe-placeholder conjugate) (Intermediate I) and begins displacing the DNA probe from the placeholder via branch migration (Intermediate II), and finally releases the placeholder from the nanoparticle system. This allows the stem-loop structure to “close” and moves the Raman label onto the plasmonics-active surface of the nanostar yielding a strong SERS signal (‘On’ status).
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As a proof of concept, the human radical S-adenosyl methionine domain containing 2 (RSAD2) gene, known to be a host-response biomarker for infections diseases, 16,17 was used as the model system to demonstrate feasibility of this SERS nanobiosensor. In this study, the AuNS seeds and AuNS@Ag
69 70 71 72
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Results
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The feasibility of using the SERS nanobiosensor for nucleic acid detection is demonstrated in Figure 2, A. In the presence of 1 μM target DNA (curve c), the SERS intensity was significantly increased indicating that the hybridization between targets and placeholders enabled the formation of the stem-loop structure of the nanobiosensor, thereby moving the SERS dye onto the nanostar surface and turning the SERS signal “On”. The success of the detection using the nanobiosensor was further confirmed by an alternative fluorescence quenching and recovery experiment (Figure S1). To evaluate the effective reaction time of the nanobiosensor, the “Off” nanobiosensor was incubated with 1 μM complementary targets at 37 °C in PBS followed by the SERS measurements at different time points. Figure 2, B shows that the nanobiosensor can be effectively turned on in 10 min, and the signal was further slightly increased by extending the reaction time to 1 h.
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Figure 1. (A) Detection scheme of the SERS nanobiosensor. (B) TEM images of the synthesized AuNS seeds and AuNS@Ag.
were prepared according to our previous reports. 12,13 Further details regarding DNA probe sequences, nanobiosensor synthesis and assay procedure can be found in the Supplementary Materials.
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Discussion
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The novel nanobiosensor developed in this study provides a simple and efficient nucleic acid assay system. As a proof of concept, we first designed the placeholder with a moderate, 8-base toehold containing equal numbers of G/C and A/T bases. According to a previous study, 18 the kinetics of strand displacement can be modulated by changing the length or the sequence composition (i.e. G/C content) of toeholds. Thus, the effective reaction time for turning on the SERS signal will depend on the toeholds used, e.g. using a strong toehold with a higher G/C content would result in a faster reaction rate. For quantitative analysis, a logarithmic fit to the data was obtained. With over 50 nM of target DNA, the SERS signal is expected to reach a plateau. However, as shown in the inset of Figure 3, a linear trend line was fitted to the data between 0 to 5 nM with a slope (s = 376.47) and a residual standard deviation (σ = 28.87). The limit of detection (LOD) (3σ/s) for target DNA
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The possibility for quantitative analysis was demonstrated by using a small sample volume (2 μL). Figure 3 illustrates that the SERS intensity at the 557 cm − 1 Raman peak increases with increasing the amount of target DNA confirming that more Raman labels were being moved close to the nanostar surface. We next evaluated the detection specificity using the perfectly matched target and sequences having one, two or three-base mismatches. Figure 4, A shows that the SERS intensity at 557 cm − 1 decreases with increasing numbers of mismatched bases. In the case of one-base mismatch, the SERS intensity is about 30% less than the perfectly matched target. To further demonstrate the capability of our system to discriminate single nucleotide differences, the nanobiosensor was tested in solutions with different ionic strength at 37 °C for 1 h. As shown in Figure 4, B, the SERS signal of the nanobiosensor treated with one-base mismatched sequences decreases with decreasing the NaCl concentration in the reaction buffer.
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Figure 3. Evaluation of the detection sensitivity of the nanobiosensor.
Figure 4. (A) Evaluation of the detection specificity of the nanobiosensor. (B) Evaluation of the single-mismatch discrimination in solutions with different ionic strength.
was determined to be ~ 0.1 nM in the current bioassay system. It is noteworthy that our analysis used very small amounts of samples (2 μL). As a result, the absolute LOD is only 200 amol. The specificity of detection is critical for many clinical applications, such as single-nucleotide polymorphism (SNP) identification or microRNA detection. It was found that reducing the ionic strength of the media could further improve the detection specificity. This is due to the fact that the mismatched target-placeholder duplex (i.e. Intermediate II) is thermodynamically unstable in low ionic strength solutions compared to the perfectly matched duplex (Table S1). Note that during the experimental process, we did not observe the aggregation of the PEG-stabilized nanobiosensor when changing the salt concentration of the buffer (Figure S2). Moreover, the reported nanobiosensor showed an excellent reproducibility with an average relative standard deviation (RSD) less than 5%. In conclusion, we have demonstrated, for the first time, the proof of concept of using the novel “OFF-to-ON” SERS nanobiosensor to detect nucleic acid targets. The nanobiosensor is a target label-free homogeneous assay as it does not require labeling targets and post-hybridization washing steps, making the procedure simple and rapid.
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Appendix A. Supplementary data
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Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.nano.2014.12.012.
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References
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1. Cao YC, Jin R, Mirkin CA. Nanoparticles with Raman spectroscopic fingerprints for DNA and RNA detection. Science 2002;297(5586):1536-40. 2. Fabris L, Dante M, Braun G, Lee SJ, Reich NO, Moskovits M, et al. A heterogeneous PNA-based SERS method for DNA detection. J Am Chem Soc 2007;129(19):6086-7. 3. Faulds K, Jarvis R, Smith WE, Graham D, Goodacre R. Multiplexed detection of six labelled oligonucleotides using surface enhanced resonance Raman scattering (SERRS). Analyst 2008;133(11):1505-12. 4. Kang T, Yoo SM, Yoon I, Lee SY, Kim B. Patterned multiplex pathogen DNA detection by Au particle-on-wire SERS sensor. Nano Lett 2010;10(4):1189-93. 5. Dougan JA, MacRae D, Graham D, Faulds K. DNA detection using enzymatic signal production and SERS. Chem Commun 2011;47(16):4649-51. 6. Li JM, Wei C, Ma WF, An Q, Guo J, Hu J, et al. Multiplexed SERS detection of DNA targets in a sandwich-hybridization assay using SERSencoded core–shell nanospheres. J Mater Chem 2012;22(24):12100-6. 7. Bantz KC, Meyer AF, Wittenberg NJ, Im H, Kurtuluş Ö, Lee SH, et al. Recent progress in SERS biosensing. Phys Chem Chem Phys 2011;13(24):11551-67.
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8. Vo-Dinh T, Yan F, Wabuyele MB. Surface-enhanced Raman scattering for medical diagnostics and biological imaging. J Raman Spectrosc 2005;36(6-7):640-7. 9. Wang HN, Vo-Dinh T. Multiplex detection of breast cancer biomarkers using plasmonic molecular sentinel nanoprobes. Nanotechnology 2009;20(6):065101. 10. Vo-Dinh T, Dhawan A, Norton SJ, Khoury CG, Wang HN, Misra V, et al. Plasmonic nanoparticles and nanowires: design, fabrication and application in sensing. J Phys Chem C 2010;114(16):7480-8. 11. Wang HN, Vo-Dinh T. Plasmonic coupling interference (PCI) nanoprobes for nucleic acid detection. Small 2011;7(21):3067-74. 12. Fales AM, Yuan H, Vo-Dinh T. Silica-coated gold nanostars for combined surface-enhanced Raman scattering (SERS) detection and singlet-oxygen generation: a potential nanoplatform for theranostics. Langmuir 2011;27(19):12186-90. 13. Fales AM, Yuan H, Vo-Dinh T. Development of hybrid silver-coated gold nanostars for nonaggregated surface-enhanced Raman scattering. J Phys Chem C 2014;118(7):3708-15. 14. Bath J, Turberfield AJ. DNA nanomachines. Nat Nanotechnol 2007;2(5):275-84. 15. Zhang DY, Seelig G. Dynamic DNA nanotechnology using stranddisplacement reactions. Nat Chem 2011;3(2):103-13. 16. Zaas AK, Chen M, Varkey J, Veldman T, Hero III AO, Lucas J, et al. Gene expression signatures diagnose influenza and other symptomatic respiratory viral infections in humans. Cell Host Microbe 2009;6(3):207-17. 17. Zaas AK, Burke T, Chen M, McClain M, Nicholson B, Veldman T, et al. A host-based RT-PCR gene expression signature to identify acute respiratory viral infection. Sci Transl Med 2013;5(203):203ra126. 18. Zhang DY, Winfree E. Control of DNA strand displacement kinetics using toehold exchange. J Am Chem Soc 2009;131(47):17303-14.
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Nanomedicine: Nanotechnology, Biology, and Medicine xx (2015) xxx – xxx nanomedjournal.com
Graphical Abstract
2 5 6
Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection
7 8
Hsin-Neng Wang, PhD a,b, Andrew M. Fales, BS a,b, Tuan Vo-Dinh, PhD a,b,c,⁎
Nanomedicine: Nanotechnology, Biology, and Medicine xxx (2015) xxx – xxx
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Department of Biomedical Engineering, Duke University, Durham, NC, USA Fitzpatrick Institute for Photonics, Duke University, Durham, NC, USA Department of Chemistry, Duke University, Durham, NC, USA
A new “turn on” plasmonics-based nanobiosensor for nucleic acid detection has been developed. This nanobiosensor integrating non-enzymatic DNA strand-displacement hybridization for specific target identification with surface-enhanced Raman scattering (SERS) detection is a target label-free and homogeneous nanoparticle-based biosensing system.
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