Au-Modified Monolayer MoS2 Sensor for DNA Detection - The Journal

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Au-Modified Monolayer MoS Sensor for DNA Detection Ke Jin, Liming Xie, Yu Tian, and Dameng Liu J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.6b01193 • Publication Date (Web): 03 May 2016 Downloaded from http://pubs.acs.org on May 9, 2016

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The Journal of Physical Chemistry

Au-Modified Monolayer MoS2 Sensor for DNA Detection Ke Jin1), Liming Xie2), Yu Tian1), Dameng Liu1)*, 1) State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, People's Republic of China

2) Key Laboratory of Standardization, and Measurement for Nanotechnology of Chinese Academy of Sciences,

CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, PR

China

Email: [email protected]

Telephone number：+86-10-62797646

ACS Paragon Plus Environment


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Abstract Recently, molybdenum disulfide (MoS2) has attracted considerable attention in the field of biomolecular detection owing to its large surface area and remarkable optoelectronic properties. Here, we report on a novel Au-modified monolayer MoS2 sensor that allows rapid, sensitive and selective detection of DNA molecules. The Au-thiol bond can effectively enhance the DNA adsorption on MoS2. With the increasing concentration of DNA solution, the photoluminescence peak shows a prominent blueshift induced by the decrease of dielectric constant around MoS2. The monolayer MoS2 nanosheet exhibits different photoluminescence properties toward single-strained DNA versus double-strained DNA. Thus, the complementary target DNA could be distinguished from mismatched DNA through the photoluminescence spectra of MoS2. The density functional theory calculation of MoS2/DNA systems was performed to explore the detection mechanism. This work could promote the research of novel sensing platform by coupling nanomaterials with biomolecular recognition events.


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1. Introduction With the rapid progress of graphene research, other two-dimensional (2D) layered materials have also attracted considerable attention due to their unique structure and remarkable physical properties.1-4 Unlike nonexistence of band gap in graphene5, 6, 2D transition metal dichalcogenide (TMD) monolayers exhibit outstanding optical and electronic properties and then have stimulated extensive studies.3,

4

For example,

MoS2 and MoSe2 monolayers have strong photoluminescence (PL) emission that is caused by the transition from indirect bandgap in bulk material to direct bandgap in single layer form.7, 8 Since their atomically thin nature, the optical and electronic properties of MoS2 monolayers would change with the surrounding environment.9. It is sensitive to particle adsorption, which acts as a dopant and then tunes the photoluminescence intensity of MoS2.10 Moreover, monolayer MoS2 flakes have large surface area making them suitable to adsorb biomolecules.11 Therefore, MoS2 monolayers could be used as a sensing platform to detect DNA nucleoside sequences through PL measurements.

Biomolecular detection plays an important role in the fields of disease diagnostics, industrial and environmental monitoring, and biomolecular analysis,12, 13 which has motivated significant interest in developing rapid, sensitive and selective detection of DNA and other small biomolecules.14, 15 Then, the optical and electrical detection methods based on the fluorescent or electrochemical labels have been widely used， which involve more complicated and high-cost procedures comparing with label-free



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detection.11 Recently, nanomaterials have been used as novel biosensors due to their unique optical, electronic, and catalytic properties.15-20 Zhu et al.16 reported that a single-layer MoS2 nanosheet possesses high fluorescence quenching ability and could be employed as a fluorogenic nanoprobe for the detection of DNA and small molecules. Huang et al.21 developed a novel microfluidic biosensor based on single-layered MoS2 nanosheets for the ultrasensitive and visual detection of DNA. Loan et al.11 fabricated graphene/MoS2 heterostructure films to label-free and selectively detect DNA hybridization through measuring the change of PL peak intensity. Though high sensitivity and selectivity can be achieved by existing methods, it is also necessary to explore a simple and direct approach for the rapid detection of DNA molecules.

In this paper, we report that an Au-modified monolayer MoS2 film provides a rapid and sensitive sensing platform for the detection of DNA hybridization based on the PL spectroscopy measurement. A30-thiol-Au-MoS2 system, including a monolayer MoS2, Au nanoparticles and thiol modified A30, is built as a sensor to perform this test. We selected single-stranded A30 as a probe to detect the complementary target DNA T30 according to the Watson-Crick base-pairing rules. The A30 probes were modified with thiol (-SH) in order to bond with the Au nanoparticles on MoS2 surface and thus enhanced the adsorbance. The PL peak position of Au-modified MoS2 sensor would display an entirely different shift tendency with increasing solution concentration when probe DNAs were mixed with the complementary DNAs and mismatched


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DNAs. Therefore, we could distinguish T30 chains from C30 chains through analyzing the PL spectra of MoS2. This detection method is simple and can be finished within a few minutes.

2. Experimental and Theoretical Methods Preparation of DNA solutions. All the DNA oligonucleotides used in this study were synthesized and purified by Beijing SBS Genetech Co., Ltd. (China). The single-strain sequence of these oligonucleotides are presented below: A30: 5’-AAA-AAA-AAA-AAA-AAA-AAA-AAA-AAA-AAA-AAA-3’ A30-SH: 5’-AAA-AAA-AAA-AAA-AAA-AAA-AAA-AAA-AAA-AAA-SH-3’ C30: 5’-CCC-CCC-CCC-CCC-CCC-CCC-CCC-CCC-CCC-CCC-3’ C30-SH: 5’-CCC-CCC-CCC-CCC-CCC-CCC-CCC-CCC-CCC-CCC-SH-3’ T30: 5’-TTT-TTT-TTT-TTT-TTT-TTT-TTT-TTT-TTT-TTT-3’ The assigned concentrations of DNA solutions were prepared by dissolving and diluting them with 1×TE buffer (10mM Tris-HCl, lmM EDTA, pH 8.0), which was purchased from Beijing Solarbio Science & Technology Co., Ltd. (China). PL and Raman scattering spectroscopy measurements. They were carried out at room temperature using a Jobin-Yvon HR800 system with laser excitation wavelength of 532 nm and a spectral resolution of ~0.6cm-1. The laser power was less than 0.4mW to avoid heating the samples. Density functional theory (DFT) Calculation. All calculations are performed with the plane-wave pseudopotential code CASTEP. PBE-style generalized gradient



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approximation is used for exchanged-correlation energy with the standard ultra-soft pseudopotential provided in the package. The van der Walls correction is introduced in the Grimme’s scheme22-24. DNA chain T3 is used instead of T30 due to the limitation of DFT computational cost. An 8x8 MoS2 supercell is used as substrate for DNA. Only Γ point is used for reciprocal space integration. The geometry is relaxed until the residual force is smaller than 0.02eV/Å.

3. Results and Discussion

Figure 1 Schematic illustration of the DNA detection method using the A30-thiol-Au-MoS2 system.

Figure

1

depicts

the

schematic

for

the

DNA detection

process

using

A30-thiol-Au-MoS2 system. Based on the large-area flat surface, MoS2 could adsorb single-stranded A30 probe via the van der Waals force between the nucleobases and the basal plane of MoS216, 21. In order to enhance the adsorbance of A30 probes by means of Au-thiol bond, the Au nanoparticles were deposited on MoS2 monolayers and the A30 probes were modified with thiol at their 3’ termini, which we denote as


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A30-SH. Then, we performed the PL spectrum measurement of A30-Au-modified MoS2 monolayers covered by different concentrations of DNA solutions. The change of dielectric environment induced by DNA adsorption could modulate the band-gap energy of MoS225, resulting in peak position shift of monolayer MoS2 PL spectroscopy. Therefore, the A30-SH-Au-MoS2 system is expected to provide a new method of DNA detection.

In our experiments, single-layer MoS2 films were mechanically exfoliated from bulk MoS2 crystals (SPI Supplies) by Scotch tape and were then deposited onto the Si substrates with a 300nm thick SiO2.26, 27 The thickness of MoS2 samples were firstly identified through the optical contrast by optical microscopy, as shown in Figure 2(a). Then, the number of layers was accurately determined by atomic force microscope (AFM)27, 28. The height of monolayer MoS2 on SiO2 substrate is about ~0.8nm, as shown in Figure 2(b). Figure 2(c) displays the two characteristic peaks including E2g1 (~386cm-1) and A1g (~404cm-1) in the Raman spectrum of pristine MoS2 film corresponding to Figure 2(a). The frequency difference between two Raman active modes is about 18cm-1, confirming that it is MoS2 monolayer.4, 29 To self-assemble the Au nanoparticles on MoS2, the samples were immersed in Au colloidal solution for 6– 8 h with a 1V external electrical field.30, 31 The colloidal Au nanoparticles with an average size of 20nm were synthesized by Frens' method32 and the scanning electron microscope（SEM）images were displayed in Figure 2(d). The PL spectra of pristine MoS2 monolayer film in Figure 2(e) shows one prominent narrow peak at 1.84eV (674nm) and one board peak at 1.97eV (629nm), which respectively correspond to the



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A1 and B1 direct exciton transition at K point of Brillouin zone induced by the spin-orbital splitting of the valence band.8 The narrow peak showed a tiny blueshift after the Au nanoparticles was deposited on monolayer MoS2 film, which attributed to the fact that the Au nanoparticle acted as a p-type dopant in the MoS2 layer.10

Figure 2 (a) Optical microscopy image of a pristine MoS2 monolayer. (b) AFM image and (c) Raman spectrum of the pristine MoS2 monolayer. (d) SEM images of the MoS2 monolayer after Au nanoparticles self-assembly. (e) PL spectra of the MoS2 monolayer before and after Au nanoparticles self-assembly.


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Figure 3 The PL spectra of Au-modified monolayer MoS2 in the presence of different concentrations of (a) A30-SH, (b) C30-SH DNA solution. The PL peak position offset of Au-modified monolayer MoS2 in the presence of different concentrations of (c) thiol-modified, (d) non-modified DNA solution.

After obtaining the Au-modified monolayer MoS2, we performed the PL measurements in the presence of different concentrations of A30-SH and C30-SH DNA solution, respectively. PL spectra of MoS2 monolayers with different solution surroundings are shown in Figure 3(a) and 3(b), the PL emission peak of MoS2 displays a prominent blueshift with increasing the concentration of DNA solution. We also conducted the same experiments with non-modified DNA solution and the results were summarized in Figure 3(d). As we can see, the PL peak position of MoS2 shows



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no prominent shift with increasing DNA solution concentration. It indicates that the non-modified DNA adsorbance of Au-modified MoS2 surface is limited and easy saturation. According to Figure 3(c) and 3(d), the PL peak position of MoS2 continually blue shifts with increasing thiol-modified DNA solution concentration and the offset increases about one order of magnitude compared with non-modified DNA solution. This demonstrates that the DNA adsorbance of MoS2 surface could be significantly enhanced through the bond formation between Au and thiol. In addition, as shown in Figure 3(d), the order of PL peak position offsets of MoS2 covered by different DNA solution is A>T>C, which is in accordance with the theoretical calculation using first principles DFT with vdW-DF method.33 The result indicates that DNA A30 has the strongest binding energy with MoS2. Therefore, we finally choose A30-SH as a probe to detect other DNA nucleosides based on the Au-modified monolayer MoS2 sensing platform.


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Figure 4 The PL spectra of Au-modified monolayer MoS2 in the presence of different concentrations of (a) A30-SH/T30, (b) A30-SH/C30 DNA solution. (c) The PL peak position offset of Au-modified monolayer MoS2 in the presence of different concentrations of A30-SH/T30 and A30-SH/C30 DNA solution. (d) The PL peak position offset of A30-SH-Au-MoS2 system when A30-SH probes hybridized with T30 and C30 at different solution concentrations.

Then, we detected the PL spectroscopy of the MoS2 sensor after A30-SH probes hybridized with the complementary target DNA T30 and mismatched DNA C30 at various concentrations for 5 min. As shown in Figure 4(a), when the target T30s are bonded to the probe A30s forming double-stranded DNAs, there is no pronounced PL peak position shift of MoS2 as a function of DNA concentration. This result implies that the double-stranded DNAs nearly have no influence on the band-gap energy of



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MoS2. By contrast, when the mismatched DNA C30 solution is used for hybridization, the PL emission peak of MoS2 exhibits an obvious blueshift trend with the increasing DNA concentration as shown in Figure 4(b) and 4(c), which is similar with that of A30-SH in Figure 3(c). In order to explicitly reveal the change of MoS2 PL spectrum when A30-SH probes hybridized with T30 and C30 at different solution concentrations, the PL peak position offset in comparison to that of original A30-SH are shown in Figure 4(d). According to the different shift tendency, we could distinguish between target T30 and mismatched C30 through the PL spectra of MoS2.


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Figure 5 Atomic structure of (a) single-stranded DNA (A) (ssDNA), (b) double-stranded DNA (T+A) (dsDNA), (c) MoS2/ssDNA system and (d) MoS2/dsDNA system.

In order to study its adsorption mechanism of the DNA-SH-Au-MoS2 system, we performed DFT calculation of the MoS2/DNA systems. It is shown that the double-strained DNA (T+A) (dsDNA) has weak interaction with MoS2. The distance for the double DNA chain is 2Å longer than single-strained pure A DNA (ssDNA), as shown in Figure 5(c), 5(d). The adsorption energy of dsDNA is less than 0.05eV while that of ssDNA is larger than 0.2eV. Therefore the dielectric screening effects of the MoS2 are different for double string and single string DNA chains. The weak interaction of dsDNA weakens the dielectric screening from the ssDNA case and leads to a redshift in PL spectrum. The similar effects have been observed and explained in carbon nanotube (CNT) surrounded by DNA chains before.25 We observed the similar trend and the same order of magnitude of redshift in MoS2 as in CNT both surrounded by DNA. It is well known that chirality control has been hindering the CNT application. The chemical vapor deposition (CVD) grown CNT could not have a good uniform chirality and thus hard to give a uniform PL spectrum. MoS2, on the contrary, has a perfect PL peak no matter from exfoliated or from CVD grown samples. Therefore MoS2-based sensor should be much more easier to fabricate and calibrate than CNT-based sensor.



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Figure 6 Schematic illustration for the (a) single-stranded DNA (A) (ssDNA) and (b) double-stranded DNA (T+A) (dsDNA) adsorbed on Au-modified MoS2 surface.

The aforementioned results and discussions prove that the detection of DNA molecules with the photoluminescence from the Au-modified monolayer MoS2 sensor is feasible. In order to further explain the detection mechanism, Figure 6(a) and 6(b) depict the schematic illustration of the adsorbed ssDNA and dsDNA on MoS2 surface. According to the DFT calculation results, the ssDNA could absolutely bind to the surface of MoS2 and modulate the dielectric environment of MoS2. As the ssDNA is hybridized with its complementary DNA, the interaction between the formed dsDNA and MoS2 is so weak that it would be far away from the surface of MoS2, resulting in the dielectric environment transforming from DNA to water. By analogy with the research of carbon nanotubes,25,

34

the exciton binding energy of MoS2 scales as

E ∝ m / ε 2 , where m is the effective mass and ε is the dielectric constant around the

MoS2. With this scaling, the emission energy for a DNA covered MoS2 is then

E = Am

1

εi2

(1)


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Approximating the dielectric constant of the ssDNA or dsDNA covered MoS2 using an effective medium gives

ε i = α iε DNA + (1 − α i )ε water

(2)

Here, ε DNA and ε water are the dielectric constants of DNA (4.0)25 and water (80.2), α i is the ratio of surface area covered by DNA per total area, which decreases in transforming from the ssDNA to dsDNA, and A is the empirical parameters. Then the change in emission energy of MoS2 covered from ssDNA to dsDNA is

∆E = Am(

1

ε dsDNA

2

−

1

ε ssDNA 2

)

(3)

Eq. (3) indicates that the dsDNA adsorption on MoS2 results in a larger dielectric constant surrounding of MoS2 in comparison with ssDNA and thus decreases its emission energy, which is the reason of redshift and in agreement with the experimental results. In addition, according to Eq. (1) and Eq. (2), the emission energy shows a blueshift with the increasing concentration of solution, which is caused by the decrease of dielectric constant around MoS2 and corresponding to the experimental results of probe and mismatched ssDNA.

4. Conclusions In conclusion, we have devised a DNA-SH-Au-MoS2 sensing system and the photoluminescence characteristics of Au-modified monolayer MoS2 are used for rapid and selective detection of DNA nucleoside chains. The DNA adsorption on MoS2 was enhanced about one order of magnitude by means of the Au-SH interaction. The single-stranded A30-SH is selected as a probe to detect other DNA nucleosides due to



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its strongest binding energy with MoS2. When the probe is hybridized with its complementary DNAs forming dsDNAs, the PL emission peak of MoS2 displays a ~0.08eV redshift, which results from the modification of dielectric environment. The first principles DFT calculations of MoS2/DNA systems are performed to clear its mechanism. The results show that the dsDNA has a weak interaction with MoS2 and thus weakens the dielectric screening from the ssDNA case. We also calculate the change of emission energy for MoS2 covered from ssDNA to dsDNA based on energy scaling formula, which is in agreement with the redshift experimental results. Compared to other nanomaterials such as carbon nanotube, MoS2-based sensor can be much more easier to fabricate and calibrate. In addition, the testing process could be finished within a few minutes, which provides a simple and rapid method for DNA detection. We believe that the emerging 2D nanomaterials would have widespread applications in the field of biological detection.

Acknowledgements This work is supported by the National Natural Science Foundation of China (No. 51575298, 51527901,51105222), and Beijing Research Program (No. 100322002).

Reference (1). Novoselov KS; Castro Neto AH. Two-Dimensional Crystals-Based Heterostructures: Materials with Tailored Properties. Physica Scripta. 2012;T146:014006. (2). Xu M; Liang T; Shi M; Chen H. Graphene-Like Two-Dimensional Materials. Chemical Reviews. 2013;113(5):3766-98. (3). Wang QH; Kalantar-Zadeh K; Kis A, Coleman JN; Strano MS. Electronics and Optoelectronics of Two-Dimensional Transition Metal Dichalcogenides. Nature Nanotechnology. 2012;7(11):699-712.


Page 16 of 26

Page 17 of 26

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(4). Zhang X; Qiao XF; Shi W; Wu JB; Jiang DS; Tan PH. Phonon and Raman Scattering of Two-Dimensional Transition Metal Dichalcogenides from Monolayer, Multilayer to Bulk Material. Chem Soc Rev. 2015;44(9):2757-85. (5). Tsurumi J; Saito Y; Verma P. Evaluation of the Interlayer Interactions of Few Layers of Graphene. Chemical Physics Letters. 2013;557:114-7. (6). Dashora A; Ahuja U; Venugopalan K. Electronic and Optical Properties of MoS2 (0001) Thin Films: Feasibility for Solar Cells. Computational Materials Science. 2013;69:216-21. (7). Tongay S; Zhou J; Ataca C; Lo K; Matthews TS; Li J, et al. Thermally Driven Crossover from Indirect toward

Direct

Bandgap

in

2D

Semiconductors:

MoSe2

versus

MoS2.

Nano

Letters.

2012;12(11):5576-80. (8). Splendiani A; Sun L; Zhang Y; Li T; Kim J; Chim C-Y, et al. Emerging Photoluminescence in Monolayer MoS2. Nano Letters. 2010;10(4):1271-5. (9). Mao N; Chen Y; Liu D; Zhang J; Xie L. Solvatochromic Effect on the Photoluminescence of MoS2 Monolayers. Small. 2013;9(8):1312-5. (10). Singha SS; Nandi D; Singha A. Tuning the Photoluminescence and Ultrasensitive Trace Detection Properties of Few-Layer MoS2 by Decoration with Gold Nanoparticles. RSC Adv. 2015;5(31):24188-93. (11). Loan PT; Zhang W; Lin CT; Wei KH; Li LJ; Chen CH. Graphene/MoS2 Heterostructures for Ultrasensitive Detection of DNA Hybridisation. Advanced Materials. 2014;26(28):4838-44. (12). Heller MJ. DNA Microarray Technology: Devices, Systems, and Applications. Annual Review of Biomedical Engineering. 2002;4:129-53. (13). McGlennen RC. Miniaturization Technologies for Molecular Diagnostics. Clinical Chemistry. 2001;47(3):393-402. (14). Li F; Huang Y; Yang Q; Zhong Z; Li D; Wang L, et al. A Graphene-Enhanced Molecular Beacon for Homogeneous DNA Detection. Nanoscale. 2010;2(6):1021-6. (15). He S; Song B; Li D; Zhu C; Qi W; Wen Y, et al. A Graphene Nanoprobe for Rapid, Sensitive, and Multicolor Fluorescent DNA Analysis. Advanced Functional Materials. 2010;20(3):453-9. (16). Zhu C; Zeng Z; Li H; Li F; Fan C; Zhang H. Single-Layer MoS2-Based Nanoprobes for Homogeneous Detection of Biomolecules. Journal of the American Chemical Society. 2013;135(16):5998-6001. (17). Min SK; Kim WY; Cho Y; Kim KS. Fast DNA Sequencing with a Graphene-Based Nanochannel Device. Nature Nanotechnology. 2011;6(3):162-5. (18). Thomas S; Rajan AC; Rezapour MR; Kim KS. In Search of a Two-Dimensional Material for DNA Sequencing. The Journal of Physical Chemistry C. 2014;118(20):10855-8. (19). Huang J; Ye L; Gao X; Li H; Xu J; Li Z. Molybdenum Disulfide-Based Amplified Fluorescence DNA Detection Using Hybridization Chain Reactions. J Mater Chem B. 2015;3(11):2395-401. (20). Rajan AC; Rezapour MR; Yun J; Cho Y; Cho WJ; Min SK, et al. Two Dimensional Molecular Electronics Spectroscopy for Molecular Fingerprinting, DNA Sequencing, and Cancerous DNA Recognition. ACS Nano. 2014;8(2):1827-33. (21). Huang Y; Shi Y; Yang HY; Ai Y. A Novel Single-Layered MoS2 Nanosheet Based Microfluidic Biosensor for Ultrasensitive Detection of DNA. Nanoscale. 2015;7(6):2245-9. (22). Grimme S. Accurate Description of van der Waals Complexes by Density Functional Theory Including Empirical Corrections. Journal of Computational Chemistry. 2004;25(12):1463-73. (23). Grimme S. Semiempirical GGA-Type Density Functional Constructed with a Long-Range Dispersion Correction. Journal of Computational Chemistry. 2006;27(15):1787-99. (24).Korth M; Grimme S. “Mindless” DFT Benchmarking. Journal of Chemical Theory and Computation.



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Page 18 of 26

2009;5(4):993-1003. (25). Heller DA; Jeng ES; Yeung T-K; Martinez BM; Moll AE; Gastala JB, et al. Optical Detection of DNA Conformational Polymorphism on Single-Walled Carbon Nanotubes. Science. 2006;311(5760):508-11. (26). Novoselov KS; Jiang D; Schedin F; Booth TJ; Khotkevich VV; Morozov SV, et al. Two-Dimensional Atomic Crystals. Proceedings of the National Academy of Sciences of the United States of America. 2005;102(30):10451-3. (27). Li H; Zhang Q; Yap CCR; Tay BK; Edwin THT; Olivier A, et al. From Bulk to Monolayer MoS2: Evolution of Raman Scattering. Advanced Functional Materials. 2012;22(7):1385-90. (28). Chakraborty B; Matte HSSR; Sood AK; Rao CNR. Layer-Dependent Resonant Raman Scattering of a Few Layer MoS2. Journal of Raman Spectroscopy. 2013;44(1):92-6. (29). Plechinger G; Heydrich S; Eroms J; Weiss D; Schüller C; Korn T. Raman Spectroscopy of the Interlayer Shear Mode in Few-Layer MoS2 Flakes. Applied Physics Letters. 2012;101(10):101906. (30). Tian R-h; Rao TN; Einaga Y; Zhi J-f. Construction of Two-Dimensional Arrays Gold Nanoparticles Monolayer

onto

Boron-Doped

Diamond

Electrode

Surfaces.

Chemistry

of

Materials.

2006;18(4):939-45. (31). Grabar KC; Freeman RG; Hommer MB; Natan MJ. Preparation and Characterization of Au Colloid Monolayers. Analytical Chemistry. 1995;67(4):735-43. (32). Frens G. Controlled Nucleation for the Regulation of the Particle Size in Monodisperse Gold Suspensions. Nature Physical Science. 1973;241:20-2. (33). Vovusha H; Sanyal B. Adsorption of Nucleobases on 2D Transition-Metal Dichalcogenides and Graphene Sheet: A First Principles Density Functional Theory Study. RSC Adv. 2015;5(83):67427-34. (34). Perebeinos V; Tersoff J; Avouris P. Scaling of Excitons in Carbon Nanotubes. Phys Rev Lett. 2004;92(25 Pt 1):257402.


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Figure 1 Schematic illustration of the DNA detection method using the A30-thiol-Au-MoS2 system. 293x88mm (150 x 150 DPI)


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Figure 2 (a) Optical microscopy image of a pristine MoS2 monolayer. (b) AFM image and (c) Raman spectrum of the pristine MoS2 monolayer. (d) SEM images of the MoS2 monolayer after Au nanoparticles self-assembly. (e) PL spectra of the MoS2 monolayer before and after Au nanoparticles self-assembly. 289x160mm (150 x 150 DPI)



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Figure 3 The PL spectra of Au-modified monolayer MoS2 in the presence of different concentrations of (a) A30-SH, (b) C30-SH DNA solution. The PL peak position offset of Au-modified monolayer MoS2 in the presence of different concentrations of (c) thiol-modified, (d) non-modified DNA solution. 221x167mm (150 x 150 DPI)


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Figure 4 The PL spectra of Au-modified monolayer MoS2 in the presence of different concentrations of (a) A30-SH/T30, (b) A30-SH/C30 DNA solution. (c) The PL peak position offset of Au-modified monolayer MoS2 in the presence of different concentrations of A30-SH/T30 and A30-SH/C30 DNA solution. (d) The PL peak position offset of A30-SH-Au-MoS2 system when A30-SH probes hybridized with T30 and C30 at diffferent solution concentrations. 237x162mm (150 x 150 DPI)



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Figure 5 Atomic structure of (a) single-stranded DNA (A) (ssDNA), (b) double-stranded DNA (T+A) (dsDNA), (c) MoS2/ssDNA system and (d) MoS2/dsDNA system. 246x232mm (150 x 150 DPI)


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Figure 6 Schematic illustration for the (a) single-stranded DNA (A) (ssDNA) and (b) double-stranded DNA (T+A) (dsDNA) adsorbed on Au-modified MoS2 surface. 255x96mm (150 x 150 DPI)



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Table of Contents (TOC) Image 303x160mm (150 x 150 DPI)


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Au-Modified Monolayer MoS2 Sensor for DNA Detection - The Journal

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