Reagent-free total protein quantification of intact extracellular vesicles by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy

• DOI: 10.1007/s00216-020-02711-8
• Publication Date: 2020-05-29T04:08:02Z
• Authors: Veronika Szentirmai; András Wacha; Csaba Németh; Diána Kitka; Anita Rácz; Károly Héberger; Judith Mihály; Zoltán Varga
• Keywords: Attenuated total reflection; Bovine serum albumin; Chemometrics

Abstract Extracellular vesicles (EVs) are lipid bilayer–bounded particles that actively synthesized and released by cells. The main components of EVs lipids, proteins, nucleic acids their composition is characteristic to type origin, it reveals the physiological pathological conditions parent concentration protein closely relate functions; therefore, total determination can assist in EV-based diagnostics disease prognosis. Here, we present a simple, reagent-free method based on attenuated reflection Fourier transform infrared (ATR-FTIR) spectroscopy quantify content EV samples without any further sample preparation. After calibration with bovine serum albumin, red blood cell–derived (REVs) were investigated ATR-FTIR spectroscopy. integrated area amide I band was calculated from IR spectra REVs, which proportional quantity sample‚ regardless its secondary structure. A spike test dilution performed determine ability use for quantification samples, resulted linearity R 2 values as high 0.992 over range 0.08 1 mg/mL. Additionally, multivariate partial least squares (PLS) regression carried out albumin spectra. 0.94 0.91 validation set. results indicate measurements provide reliable EVs.