Background

Parkinson's disease (PD) is a progressive neurodegenerative disorder lacking reliable, early-stage diagnostic biomarkers. This study utilizes Fourier Transform Infrared (FTIR) spectroscopy to identify biochemical alterations in plasma-derived small extracellular vesicles (PsEVs) from PD patients.

Methods

PsEVs were isolated and characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and immunoblotting for canonical markers (TSG101, CD63, and CD9). FTIR spectra were recorded in the mid-infrared region (900–3100 cm−1) to probe molecular signatures of lipids and proteins.

Results

Significant spectral differences were observed between PD and AM-C sEVs, in the lipid-associated regions- I2960/I2929 for CH₃/CH₂ asymmetric stretch (AUC = 0.991; Sn = 100%, Sp = 86.67%), I3040/I2929 for olefinic/saturated lipid ratios (AUC = 0.973; Sn = 96.67%, Sp = 86.67%), and protein-associated amide-I region, using Erik Goormaghtigh's MATLAB Kinetics and demonstrated a strong discriminatory power. Multivariate PCA and hierarchical clustering analyses also confirmed clear segregation.

Conclusion

FTIR revealed lipid-based spectral biomarkers in PsEVs, highlighting their potential for early diagnostic tools for PD screening and monitoring.