A specific spectral signature of serum and plasma-derived extracellular vesicles for cancer screening

In cancer, extracellular vesicles (EV) contribute to tumor progression by regulating local and systemic effects. Being released into body fluids, EV may be used in nanomedicine as a valuable source for diagnostic biomarkers. In this work, infrared and Raman spectroscopy were used for comprehensive comparative analysis of cancer versus non-cancer EV and patient screening. Two different EV fractions enriched in exosomes and microvesicles were isolated by differential centrifugation from serum and plasma of cancer and non-cancer patients and from serum and plasma of a healthy donor. The EV fractions were then subjected to drop-coating deposition and drying on calcium fluoride substrates. Reduction of alpha-helix-rich proteins and enhancement of beta-sheet-rich proteins as a cancer-specific blood EV signature was determined, and subsequently this feature was applied for a pilot study aiming to detect prostate cancer in a test cohort of patients with high-grade prostate carcinoma and benign hypoplasia.