Raman spectral study of metal–cytosine complexes: A density functional theoretical (DFT) approach

Shuan-jiang, Liu; Zheng, Guimei; Li, Jianxin

doi:10.1016/j.saa.2011.05.049

Cited by 19 publications

(19 citation statements)

References 55 publications

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“…To extend the potential of these SERS targets explored by probing bio-organic molecules, we have also investigated the SERS spectrum of a nucleobase such as a cytosine. 45,46 To characterize the nucleobase, different density of Ag NPs decorated vertically aligned Si NWs have been utilized. Figure 12 presents the Raman scattering data of AP explosives with 10 lM concentration.…”

Section: Resultsmentioning

confidence: 99%

Three-dimensional hybrid silicon nanostructures for surface enhanced Raman spectroscopy based molecular detection

Vendamani

Rao

Kanjilal

et al. 2018

Journal of Applied Physics

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Three-dimensional silver nanoparticles decorated vertically aligned Si nanowires (Si NWs) are effective surface-enhanced Raman spectroscopy (SERS) substrates for molecular detection at low concentration levels. The length of Si NWs prepared by silver assisted electroless etching is increased with an increase in etching time, which resulted in the reduced optical reflection in the visible region. These substrates were tested and optimized by measuring the Raman spectrum of standard dye Rhodamine 6G (R6G) of 10 nM concentration. Further, effective SERS enhancements of $10 5 and $10 4 were observed for the cytosine protein (concentration of 50 lM) and ammonium perchlorate (oxidizer used in explosives composition with a concentration of 10 lM), respectively. It is established that these three-dimensional SERS substrates yielded considerably higher enhancement factors for the detection of R6G when compared to previous reports. The sensitivity can further be increased and optimized since the Raman enhancement was found to increase with an increase in the density of silver nanoparticles decorated on the walls of Si NWs.

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Section: Resultsmentioning

confidence: 99%

Three-dimensional hybrid silicon nanostructures for surface enhanced Raman spectroscopy based molecular detection

Vendamani

Rao

Kanjilal

et al. 2018

Journal of Applied Physics

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“…Raman energies in both DNA samples are found at 1324, 1407 (weak), 1473, and 1567 cm À1 . They can be assigned to the C 5 ¼C 6 stretching mode, N 1 -H and C 6 -H bending modes, C 4 ¼N 3 stretching mode, and C 4 -NH 2 bending mode, respectively (26,27,(38)(39)(40)(41)(42). The primary differences are two additional Raman peaks in the 1200-1700 cm À1 band with methylation: one at 1239 cm À1 and the other at 1639 cm À1 .…”

Section: Resultsmentioning

confidence: 99%

DNA Methylation Detection Using Resonance and Nanobowtie-Antenna-Enhanced Raman Spectroscopy

Lim

Puretzky

et al. 2018

Biophysical Journal

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We show that DNA carrying 5-methylcytosine modifications or methylated DNA (m-DNA) can be distinguished from DNA with unmodified cytosine by Raman spectroscopy enhanced by both a bowtie nanoantenna and excitation resonance. In particular, m-DNA can be identified by a peak near 1000 cm and changes in the Raman peaks in the 1200-1700 cm band that are enhanced by the ring-absorption resonance. The identification is robust to the use of resonance Raman and nanoantenna excitation used to obtain significant signal improvement. The primary differences are three additional Raman peaks with methylation at 1014, 1239, and 1639 cm and spectral intensity inversion at 1324 (C=C) and 1473 cm (C=N) in m-DNA compared to that of DNA with unmodified cytosine. We attribute this to the proximity of the methyl group to the antenna, which brings the (C=C) mode closer to experiencing a stronger near-field enhancement. We also show distinct Raman spectral features attributed to the transition of DNA from a hydrated state, when dissolved, to a dried/denatured state. We observe a general broadening of the larger lines and a transfer of spectral weight from the ∼1470 cm vibration to the two higher-energy lines of the dried m-DNA solution. We attribute the new spectral characteristics to DNA softening under high salt conditions and find that the m-DNA is still distinguishable via the ∼1000 cm peak and distribution of the signal in the 1200-1700 cm band. The nanoantenna gain exceeds 20,000, whereas the real signal ratio is much less because of a low average enhanced region occupancy even with these relatively high DNA concentrations. It is improved when fixed DNA in a salt crystal lies near the nanoantenna. The Raman resonance gain profile is consistent with A-term expectations, and the resonance is found at ∼259 nm excitation wavelength.

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“…Specifically, Ag atoms are believed to segregate on the surface to bind the two strands together through forming Ag O coordination bonds during the annealing process. [53,54] As a result, the Cyt molecule is slightly tilted so that its O atom can bond to the Ag ad-atom effectively, and accompanying such a tilting of Cyt, the BPY molecule is tilted to opposite directions due to the steric repulsion. The unique doublestranded chain structure with a large strand-to-strand separation of about 0.9 nm is unlikely to form through intra-strand hydrogen bonding.…”

Section: Stm and Ters Study On Annealed Bicomponent Molecular Samplesmentioning

confidence: 99%

Bicomponent supramolecular self‐assemblies studied with tip‐enhanced Raman spectroscopy

Jiang

Zhang

et al. 2020

J Raman Spectroscopy

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The formation of well‐ordered supramolecular self‐assembly based on cytosine and 4,4′‐bipyridine on Ag(111) has been investigated with subnanometer‐resolved tip‐enhanced Raman spectroscopy (TERS) using a low‐temperature ultrahigh‐vacuum scanning tunneling microscope (STM). The co‐deposition of two molecules on the Ag(111) surface held at room temperature results in well‐ordered hydrogen‐bonded monolayer islands, which transform into well‐aligned double‐stranded chains after thermal annealing. Site‐dependent TERS spectra help to identify the packing structures of molecular assemblies. The changes of molecule‐specific vibrational fingerprints across the assemblies can be clearly monitored by combining high‐resolution TERS spectra with advanced multivariate analysis. Furthermore, the peak positions and relative intensities for characteristic vibrational modes of the two molecules are found to vary due to the changes of the local hydrogen bonding and interaction environment in different molecular samples. Our findings demonstrate that TERS is sensitive to the local molecular interactions, provides new potentials to monitor the functionality of molecular architectures on demand, and opens new opportunities to probe surface chemistry at the nanoscale.

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Raman spectral study of metal–cytosine complexes: A density functional theoretical (DFT) approach

Cited by 19 publications

References 55 publications

Three-dimensional hybrid silicon nanostructures for surface enhanced Raman spectroscopy based molecular detection

Three-dimensional hybrid silicon nanostructures for surface enhanced Raman spectroscopy based molecular detection

DNA Methylation Detection Using Resonance and Nanobowtie-Antenna-Enhanced Raman Spectroscopy

Bicomponent supramolecular self‐assemblies studied with tip‐enhanced Raman spectroscopy

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