title: Characterization of extracellular vesicles by IR spectroscopy: Fast and simple classification based on amide and CH stretching vibrations.
abstract: Extracellular vesicles isolated by differential centrifugation from Jurkat T-cell line were investigated by attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR). Amide and CH stretching band intensity ratios calculated from IR bands, characteristic of protein and lipid components, proved to be distinctive for the different extracellular vesicle subpopulations. This proposed 'spectroscopic protein-to-lipid ratio', combined with the outlined spectrum-analysis protocol is valid also for low sample concentrations (0.15-0.05mg/ml total protein content) and can carry information about the presence of other non-vesicular formations such as aggregated proteins, lipoproteins and immune complexes. Detailed analysis of IR data reveals compositional changes of extracellular vesicles subpopulations: second derivative spectra suggest changes in protein composition from parent cell towards exosomes favoring proteins with β-turns and unordered motifs at the expense of intermolecular β-sheet structures. The IR-based protein-to-lipid assessment protocol was tested also for red blood cell derived microvesicles for which similar values were obtained. The potential applicability of this technique for fast and efficient characterization of vesicular components is high as the investigated samples require no further preparations and all the different molecular species can be determined in the same sample. The results indicate that ATR-FTIR measurements provide a simple and reproducible method for the screening of extracellular vesicle preparations. It is hoped that this sophisticated technique will have further impact in extracellular vesicle research.
authors.affiliation: Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary. Electronic address: mihaly.judith@ttk.mta.hu.
authors.forename: Judith
authors.initials: J
authors.lastname: Mihály
authors.affiliation: Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary.
authors.forename: Róbert
authors.initials: R
authors.lastname: Deák
authors.affiliation: Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary.
authors.forename: Imola Csilla
authors.initials: IC
authors.lastname: Szigyártó
authors.affiliation: Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Bóta
authors.affiliation: Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Beke-Somfai
authors.affiliation: Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Varga
mesh_terms: D000577:Amides / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D000067493:Dynamic Light Scattering; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism; D000067128:Extracellular Vesicles / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D019169:Jurkat Cells; D046529:Microscopy, Electron, Transmission; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000577:Amides; D002244:Carbon; D006859:Hydrogen
keywords: ATR-FTIR spectroscopy; Erythrocyte ghost membrane; Exosome; Extracellular vesicles; Microvesicle; Spectroscopic protein-to-lipid ratio