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Updated: Oct 4, 2025
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Multimodal Analytical Platform on a Multiplexed Surface Plasmon Resonance Imaging Chip for the Analysis of Extracellular Vesicle Subsets
Published on: March 17, 2023
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Infrared and Raman spectroscopy for purity assessment of extracellular vesicles
Jacopo Zini1, Heikki Saari2, Paolo Ciana3
1Division of Pharmaceutical Biosciences and Drug Research Program, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland.
Summary
Spectroscopic methods, such as Raman and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, offer robust and rapid assessment of extracellular vesicle (EV) purity. Lipid-to-protein ratios derived from these techniques reliably indicate EV preparation purity.
Area of Science:
- Biotechnology
- Nanotechnology
- Analytical Chemistry
Background:
- Extracellular vesicles (EVs) are crucial for intercellular communication and show therapeutic and diagnostic potential.
- Standardized characterization methods are lacking, hindering the evaluation of EV studies.
- Diverse EV applications necessitate reliable purity and characteristic assessment.
Purpose of the Study:
- To compare four distinct methods for extracellular vesicle (EV) sample characterization and purity assessment.
- To evaluate the efficacy of spectroscopic techniques (Raman and ATR-FTIR) for EV analysis.
- To propose reliable parameters for EV purity assessment.
Main Methods:
- Particle-to-protein ratio using nanoparticle tracking and bicinchoninic acid assay.
- Western Blot analysis for specific EV biomarkers.
- Spectroscopic lipid-to-protein (Li/Pr) ratio analysis using attenuated total reflection Fourier transform infrared (ATR-FTIR) and Raman spectroscopy.
Main Results:
- Raman and ATR-FTIR spectroscopy are robust, fast, and operator-independent methods requiring minimal sample volume.
- Spectroscopic Li/Pr ratios serve as reliable indicators for EV preparation purity.
- ATR-FTIR spectroscopy can determine protein concentration and indirectly measure EV concentration.
Conclusions:
- Spectroscopic Li/Pr ratios are valuable for assessing EV purity.
- ATR-FTIR spectroscopy offers a dual function for protein and EV concentration measurements.
- Comprehensive EV characterization requires combining spectroscopic purity assessment with particle size distribution and biomarker analysis.
