scholarly journals Micro- and Nanoscale Spectroscopic Investigations of Threonine Influence on the Corrosion Process of the Modified Fe Surface by Cu Nanoparticles

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4482
Author(s):  
Dominika Święch ◽  
Czesława Paluszkiewicz ◽  
Natalia Piergies ◽  
Ewa Pięta ◽  
Kamila Kollbek ◽  
...  
Keyword(s):  
Metal Surface ◽  
Vibrational Analysis ◽  
Surface Enhanced Raman Spectroscopy ◽  
Cu Nanoparticles ◽  
Force Microscopy ◽  
Carboxylate Groups ◽  
Protonated Amine ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Adsorption Geometry

The work presents a comprehensive vibrational analysis of the process of adsorption of threonine (Thr) onto an Fe surface with deposited Cu nanoparticles (NPs) (of about 4–5 nm in size) in a corrosive environment. The application of surface-enhanced Raman spectroscopy (SERS) and surface-enhanced infrared absorption spectroscopy (SEIRA) provides the opportunity for detailed description of adsorption geometry of amino acid onto a metal surface. The combination of conventional infrared spectroscopy (IR) with atomic force microscopy (AFM) resulted in a nano-SEIRA technique which made it possible to provide a precise description of adsorbate binding to the metal surface. The studies presented confirmed that there is a very good correlation between the spectra recorded by the SERS, SEIRA, and nano-SEIRA techniques. Threonine significantly influenced the process of corrosion of the investigated surface due to the existing strong interaction between the protonated amine and carboxylate groups and the CuNPs deposited onto the Fe surface. In addition, the application of two polarization modulations (s and p) in nano-SEIRA allows subtle changes to be observed in the molecule geometry upon adsorption, with the carboxylate group of Thr being almost horizontally oriented onto the metal surface; whereas the amine group that contains nitrogen is oriented perpendicular to this surface.

scholarly journals Fabrication of Bioprobe Self-Assembled on Au–Te Nanoworm Structure for SERS Biosensor

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3234
Author(s):  
Soo Min Kim ◽  
Taek Lee ◽  
Yeong-Gyu Gil ◽  
Ga Hyeon Kim ◽  
Chulhwan Park ◽  
...  
Keyword(s):  
Surface Enhanced Raman Spectroscopy ◽  
Galvanic Replacement ◽  
Ambient Conditions ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Enhanced ◽  
Immunodeficiency Virus ◽  
Surface Enhanced Raman ◽  
Immobilized Substrate ◽  
Interconnected Structure

In the present study, we propose a novel biosensor platform using a gold-tellurium (Au–Te) nanoworm structure through surface-enhanced Raman spectroscopy (SERS). Au–Tenanoworm was synthesized by spontaneous galvanic replacement of sacrificial Te nanorods templated with Au (III) cations under ambient conditions. The fabricated Au–Te nanoworm exhibited an interconnected structure of small spherical nanoparticles and was found to be effective at enhancing Raman scattering. The Au–Te nanoworm-immobilized substrate exhibited the ability to detect thyroxine using an aptamer-tagged DNA three-way junction (3WJ) and glycoprotein 120 (GP120) human immunodeficiency virus (HIV) using an antibody. The modified substrates were investigated by scanning electron microscopy and atomic force microscopy (AFM). The optimal Au–Te nanoworm concentration and immobilization time for the thyroxine biosensor platform were further determined by SERS experimentation. Thus, the present study showed that the Au–Te nanoworm structure could be applied to various biosensor platforms.

scholarly journals Surface-enhanced Raman Spectroscopy and Density Functional Theory Study of Glyphosate and Aminomethylphosphonic acid Using Silver Capped Silicon Nanopillars

2021 ◽  
Vol 26 (1) ◽  
pp. 51-67
Author(s):  
John Castillo ◽  
Ciro Rozo ◽  
Kaiyu Wu ◽  
Tomas Rindzevicius ◽  
Anja Boisen
Keyword(s):  
Density Functional Theory ◽  
Raman Spectroscopy ◽  
Metal Surface ◽  
Density Functional ◽  
Surface Enhanced Raman Spectroscopy ◽  
Functional Theory ◽  
Binding Behavior ◽  
Aminomethylphosphonic Acid ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Glyphosate (GP) is a broad-spectrum systemic herbicide which is used for killing a wide variety of harmful plants. Several recent studies indicate possible adverse health effects on humans. This work is focused on detection and adsorption studies of GP and its metabolite aminomethylphosphonic acid (AMPA) on silver-capped silicon nanopillars using surface-enhanced Raman spectroscopy (SERS). Density Functional Theory with the B3LYP functional was employed for the geometry optimization of ground state geometries and simulation of Raman and SERS spectra of the GP and AMPA. The theoretically calculated and experimentally observed vibrations of GP and AMPA free and attached to the Ag surface exhibited different Raman spectra revealing chemical interactions between the analysed molecules and the metal surface. DFT studies confirmed that the main Ag-GP interaction is with the oxygen from carboxylic and phosphate groups, andfor AMPA the main interaction is via a strong interaction between nitrogen from NH with the metal surface. In order to study the binding behavior, adsorption isotherm analysis between GP and AMPA on silver-capped silicon nanopillars (AgNPs) were performed. Finally, the obtained isotherms for GP and AMPA followed a negative cooperative binding mechanism.

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