Determination of the Immunoglobulin G Spectrum by Surface-Enhanced Raman Spectroscopy Using Quasispherical Gold Nanoparticles
Autor: | Juan Manuel Núñez-Leyva, Alejandra Ortiz-Dosal, Luis Carlos Ortiz-Dosal, Elizabeth Loredo-García, Ana Gabriela Álvarez-Contreras, Eleazar Samuel Kolosovas-Machuca |
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Jazyk: | angličtina |
Rok vydání: | 2021 |
Předmět: |
Chromatography
Materials science Article Subject biology 010401 analytical chemistry Substrate (chemistry) Nanoparticle 02 engineering and technology Surface-enhanced Raman spectroscopy 021001 nanoscience & nanotechnology 01 natural sciences Immunoglobulin G 0104 chemical sciences Colloid symbols.namesake Colloidal gold symbols biology.protein Molecule T1-995 General Materials Science 0210 nano-technology Raman spectroscopy Technology (General) |
Zdroj: | Journal of Nanomaterials, Vol 2021 (2021) |
ISSN: | 1687-4129 1687-4110 |
Popis: | Background. Immunoglobulins (Ig) are glycoprotein molecules produced by plasma cells in response to antigenic stimuli involved in various physiological and pathological conditions. Intravenous immunoglobulin (IVIG) is a compound whose composition corresponds to Ig concentrations in human plasma, predominantly IgG. It is used as a replacement treatment in immunodeficiencies and as an immunomodulator in inflammatory and autoimmune diseases. The determination of IgG concentrations is useful in the diagnosis of these immunodeficiencies. Surface-enhanced Raman spectroscopy (SERS) is a technique that allows protein quantification in a fast and straightforward way. Objective. This study is aimed at determining the Raman spectrum of IgG at physiological concentrations using quasispherical gold nanoparticles as a SERS substrate. Methods. We initially determined the Raman spectrum of IVIG at 5%. Subsequently, for SERS’ characterization, decreasing dilutions of the protein were made by adding deionized water and an equal volume of the 5 nm gold quasispherical nanoparticle colloid. For each protein concentration, the Raman spectrum was determined using a 10x objective; we focused the 532 and 785 nm laser on the sample surface, in a range of 500-1800 cm-1, with five acquisitions and an acquisition time of 30 seconds. Results. We obtained the IVIG spectrum using SERS up to a concentration of 75 mg/dl. The Raman bands correspond to aromatic amino acid side chains and the characteristic beta-sheet structure of IgG. Conclusion. The use of 5 nm quasispherical gold nanoparticles as a SERS substrate allows for detecting the Raman spectrum of IVIG at physiological concentrations. |
Databáze: | OpenAIRE |
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