Raman and surface-enhanced Raman spectroscopy of amino acids and nucleotide bases for target bacterial vibrational mode identification

Surface Enhanced Raman Spectroscopy (SERS) has demonstrated significant benefit in the identification of biological molecules. In this paper we have examined how to identify and differentiate the 150 kDa protein myeloperoxidase (MPO) from its corresponding antibody (Ab) and their immunocomplex through the use of SERS. The SERS signal of these biological molecules was enabled by 40 nm gold nanoparticles. The SERS spectra for both MPO and the Ab (an IgG molecule) demonstrated results consistent with previous published work on the Raman spectra of MPO and IgG antibodies. The immunocomplex SERS spectra showed peak shifts and intensity variations that could be attributed to conformational changes that occur during immunocomplex formation. Several key spectral areas have been identified which correspond to specific amino acids being shielded from undergoing resonance while new amino acid residues are made visible in the SERS spectrum of the immunocomplex and could be a result of conformational binding. These results indicate that SERS can be used to identify binding events and distinguish an immunocomplex from its individual components.

Download Full-text

NIR surface enhanced Raman spectroscopy and bands assignment by DFT calculations of non-natural β-amino acids

Chemical Physics ◽

10.1016/j.chemphys.2004.10.034 ◽

2005 ◽

Vol 310 (1-3) ◽

pp. 189-199 ◽

Cited By ~ 15

Author(s):

T. Iliescu ◽

D. Maniu ◽

V. Chis ◽

F.D. Irimie ◽

Cs. Paizs ◽

...

Keyword(s):

Amino Acids ◽

Raman Spectroscopy ◽

Dft Calculations ◽

Surface Enhanced Raman Spectroscopy ◽

Surface Enhanced ◽

Surface Enhanced Raman

Download Full-text

Surface-Enhanced Raman Spectra of VX and its Hydrolysis Products

Applied Spectroscopy ◽

10.1366/0003702053946100 ◽

2005 ◽

Vol 59 (5) ◽

pp. 654-660 ◽

Cited By ~ 36

Author(s):

Stuart Farquharson ◽

Alan Gift ◽

Paul Maksymiuk ◽

Frank Inscore

Keyword(s):

Raman Spectroscopy ◽

Vibrational Mode ◽

Sol Gel ◽

Surface Enhanced Raman Spectroscopy ◽

Nerve Agent ◽

Methylphosphonic Acid ◽

Hydrolysis Products ◽

Chemical Agents ◽

Surface Enhanced ◽

Surface Enhanced Raman

Detection of chemical agents as poisons in water supplies not only requires μg/L sensitivity, but also requires the ability to distinguish their hydrolysis products. We have been investigating the ability of surface-enhanced Raman spectroscopy (SERS) to detect chemical agents at these concentrations. Here we expand these studies and present the SERS spectra of the nerve agent VX (ethyl S-2-diisopropylamino ethyl methylphosphonothioate) and its hydrolysis products, ethyl S-2-diisopropylamino methylphosphonothioate, 2-(diisopropylamino) ethanethiol, ethyl methylphosphonic acid, and methylphosphonic acid. Vibrational mode assignments for the observed SERS peaks are also provided. Overall, each of these chemicals produces a series of peaks between 450 and 900 cm−1 that are sufficiently unique to allow identification. SERS measurements were performed in silver-doped sol-gel-filled capillaries that are being developed as part of an extractive point sensor.

Download Full-text