scholarly journals SERS Microspectroscopy of Biomolecules on Dried Ag Colloidal Drops

2012 ◽  
Vol 27 ◽  
pp. 449-453 ◽  
Author(s):  
P. Šimáková ◽  
M. Procházka ◽  
E. Kočišová
Keyword(s):  
Hot Spots ◽  
Sers Spectrum ◽  
Drying Process ◽  
Colloidal Solutions ◽  
Accumulation Time ◽  
Surface Enhanced ◽  
Edge Part ◽  
Ag Colloid ◽  
Almost All ◽  
Glass Support

We report the application of dried Ag hydroxylamine-reduced colloidal drops to surface-enhanced (resonance) Raman scattering (SE(R)RS) study of biomolecules using Raman microspectroscopy. 5,10,15,20-tetrakis(1-methyl-4-pyridyl)porphyrin (TMPyP), amino acid tryptophan, and phospholipid 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) served as testing biomolecules. Ag colloid/biomolecule drop dried on glass support forms a ring in the edge part of the drop in which almost all nanoparticles are clustered. This specific drying process promotes adsorption of the studied biomolecules in highly enhancing sites (“hot spots”) as well as concentrates them in the ring. We were able to obtain SE(R)RS spectra from the ring that cannot be acquired directly from Ag colloidal solutions (SERRS spectrum of1×10−10 M TMPyP by 1 s accumulation time, SERS spectrum of2×10−7 M DSPC). Despite the spectral irreproducibility and problems with spurious bands in some cases, SERS microspectroscopy of studied biomolecules using dried Ag colloid/adsorbate systems improves SERS applicability and sensitivity in comparison to measurements directly from Ag colloidal solution.

scholarly journals Preparation of Fe3O4-Ag Nanocomposites with Silver Petals for SERS Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1288
Author(s):  
Thi Thuy Nguyen ◽  
Fayna Mammeri ◽  
Souad Ammar ◽  
Thi Bich Ngoc Nguyen ◽  
Trong Nghia Nguyen ◽  
...  
Keyword(s):  
Self Assembly ◽  
Hot Spots ◽  
Surface Enhanced Raman Spectroscopy ◽  
Electrical Field ◽  
Stabilizing Agents ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Sensing ◽  
Applied Electrical Field ◽  
Positively Charged

The formation of silver nanopetal-Fe3O4 poly-nanocrystals assemblies and the use of the resulting hetero-nanostructures as active substrates for Surface Enhanced Raman Spectroscopy (SERS) application are here reported. In practice, about 180 nm sized polyol-made Fe3O4 spheres, constituted by 10 nm sized crystals, were functionalized by (3-aminopropyl)triethoxysilane (APTES) to become positively charged, which can then electrostatically interact with negatively charged silver seeds. Silver petals were formed by seed-mediated growth in presence of Ag+ cations and self-assembly, using L-ascorbic acid (L-AA) and polyvinyl pyrrolidone (PVP) as mid-reducing and stabilizing agents, respectively. The resulting plasmonic structure provides a rough surface with plenty of hot spots able to locally enhance significantly any applied electrical field. Additionally, they exhibited a high enough saturation magnetization with Ms = 9.7 emu g−1 to be reversibly collected by an external magnetic field, which shortened the detection time. The plasmonic property makes the engineered Fe3O4-Ag architectures particularly valuable for magnetically assisted ultra-sensitive SERS sensing. This was unambiguously established through the successful detection, in water, of traces, (down to 10−10 M) of Rhodamine 6G (R6G), at room temperature.

Surface-Enhanced Resonance Raman Spectra Study of α,β,γ,δ-Tetra-(4-Trimethyl Ammonium Phenyl) Porphyrin

1993 ◽  
Vol 47 (3) ◽  
pp. 292-295 ◽  
Author(s):  
Jian Chen ◽  
Ji-Ming Hu ◽  
Zhi-San Xu ◽  
Rong-Sheng Sheng
Keyword(s):  
Group Theory ◽  
Phenyl Ring ◽  
Resonance Raman ◽  
Vibrational Modes ◽  
Molecular Symmetry ◽  
Resonance Raman Scattering ◽  
Porphyrin Macrocycle ◽  
Surface Enhanced ◽  
Ag Colloid ◽  
Resonance Raman Spectra

In the present study, surface-enhanced resonance Raman scattering (SERRS) spectra of α,β,γ,δ-tetra-(4-trimethyl ammonium phenyl) porphyrin [T(4-TAP)P] were obtained. With increasing pH, the relative intensities of the bands at 890 and 1244 cm−1 decreased. These bands were attributed to γ(C-H) and δ(Cm-phenyl), respectively. The bands at 420 and 576 cm−1, which were assigned to γ(phenyl-ring), were enhanced. The molecular symmetry of T(4-TAP)P is discussed in terms of group theory. The bands at 1554 and 1496 cm−1 could be attributed to the vibrational modes of the porphyrin macrocycle; the bands at 1460, 1362, and 1330 cm−1 were assigned to ν(C-C) + δ(C-H), ν(C-N) + δ(C-H), and ν(C-N), respectively. All these bands change in band intensities, positions and widths, with the potential changing from +0.2 V to −0.2 V. It was concluded that the adsorbed porphyrins underwent partial incorporation with Ag from the electrode, and the adsorbate assumed a flat orientation on the silver electrode as well as the Ag colloid surface.

scholarly journals Highly ordered arrays of hat-shaped hierarchical nanostructures with different curvatures for sensitive SERS and plasmon-driven catalysis

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chao Zhang ◽  
Zhaoxiang Li ◽  
Si Qiu ◽  
Weixi Lu ◽  
Mingrui Shao ◽  
...  
Keyword(s):  
Hot Spots ◽  
Hybrid Structure ◽  
Sers Substrate ◽  
Polystyrene Spheres ◽  
Hierarchical Nanostructures ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Narrow Gaps

Abstract Regulation of hot spots exhibits excellent potential in many applications including nanolasers, energy harvesting, sensing, and subwavelength imaging. Here, hat-shaped hierarchical nanostructures with different space curvatures have been proposed to enhance hot spots for facilitating surface-enhanced Raman scattering (SERS) and plasmon-driven catalysis applications. These novel nanostructures comprise two layers of metal nanoparticles separated by hat-shaped MoS2 films. The fabrication of this hybrid structure is based on the thermal annealing and thermal evaporation of self-assembled polystyrene spheres, which are convenient to control the metal particle size and the curvature of hat-shaped nanostructures. Based on the narrow gaps produced by the MoS2 films and the curvature of space, the constructed platform exhibits superior SERS capability and achieves ultrasensitive detection for toxic molecules. Furthermore, the surface catalytic conversion of p-nitrothiophenol (PNTP) to p, p′-dimercaptobenzene (DMAB) was in situ monitored by the SERS substrate. The mechanism governing this regulation of hot spots is also investigated via theoretical simulations.

Optimization of electromagnetic hot spots in surface-enhanced Raman scattering substrates for an ultrasensitive drug assay of emergency department patients’ plasma

The Analyst ◽  
2020 ◽  
Vol 145 (23) ◽  
pp. 7662-7672
Author(s):  
Thakshila Liyanage ◽  
Adrianna N. Masterson ◽  
Sumon Hati ◽  
Greta Ren ◽  
Nicholas E. Manicke ◽  
...  
Keyword(s):  
Emergency Department ◽  
Raman Scattering ◽  
Hot Spots ◽  
Surface Enhanced Raman Scattering ◽  
Ultrasensitive Detection ◽  
Drug Assay ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Emergency Department Patients

Nanoplasmonic superlattice surface-enhanced Raman scattering substrates have been developed for an ultrasensitive detection of fentanyl and cocaine from patients’ plasma.

scholarly journals Interaction of porphyrin/oligonucleotide complex with liposomes studied by drop coating deposition Raman spectroscopy

2010 ◽  
Vol 24 (3-4) ◽  
pp. 197-200 ◽  
Author(s):  
E. Kocišová ◽  
M. Procházka ◽  
J. Štepánek ◽  
P. Mojzeš
Keyword(s):  
Raman Spectroscopy ◽  
Lipid Composition ◽  
Hydrophobic Surface ◽  
Small Species ◽  
Drying Process ◽  
High Quality ◽  
Coating Deposition ◽  
Solution Sample ◽  
Plasmatic Membrane ◽  
Edge Part

Drop coating deposition Raman (DCDR) microspectroscopy was used to investigate interaction of the complexed cationic copper 5,10,15,20-tetrakis(1-methyl-4-pyridyl) porphyrin (CuP) and phosphorothioate analog of dT15oligonucleotide with liposomes, the lipid composition of which imitated the natural plasmatic membrane. Great advantage of dried drops on DCDR plates over a solution sample is that the specific drying process on the special hydrophobic surface efficiently separates liposomes from small species in the solvent. In our case, liposomes with bound CuP/oligonucleotide complexes formed a ring at the edge part of the dried drop while dried solution of this complex remained inside this ring. High quality spectra measured from the ring by using Raman confocal microspectrometer revealed unperturbed arrangement of lipid chains by the drying process, partial binding of the CuP/oligonucleotide complexes to liposomes, and a certain reorientation of lipid chains as a consequence of this interaction.

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