Raman Spectroscopy characterization extracellular vesicles from bovine placenta and peripheral blood mononuclear cells

Abstract

Placenta-derived extracellular vesicles (EVs) are involved in communication between the placenta and maternal immune cells possibly leading to a modulation of maternal T-cell signaling components. The ability to identify EVs in maternal blood may lead to the development of diagnostic and treatment tools for pregnancy complications. The objective of this work was to differentiate EVs from bovine placenta (trophoblast) and peripheral blood mononuclear cells (PBMC) by a label-free, non-invasive Raman spectroscopy technique. Extracellular vesicles were isolated by ultracentrifugation. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) were applied to verify the presence and the size distribution of EVs. Raman peaks at 728 cm-1 (collagen) and 1573 cm-1 (protein) were observed only in PBMC-derived EVs, while the peaks 702 cm-1 (cholesterol) and 1553 cm-1 (amide) appeared only in trophoblast-derived EVs. The discrimination of the Raman spectral fingerprints for both types of EVs from different animals was performed by principal component analysis (PCA) and linear discriminant analysis (LDA). The PCA and LDA results clearly segregated the spectral clusters between the two types of EVs. Moreover, the PBMC-derived EVs from different animals were indistinguishable, while the trophoblastderived EVs from three placental samples of different gestational ages showed separate clusters. This study reports for the first time the Raman characteristic peaks for identification of PBMC and trophoblast-derived EVs. The development of this method also provides a potential tool for further studies investigating the causes and potential treatments for pregnancy complications.

Surface enhanced Raman scattering of extracellular vesicles for cancer diagnostics despite isolation dependent lipoprotein contamination

“…Signal analysis by PCA followed by LDA has been successfully applied to discriminate EVs in previous work. 73,74 In this limited dataset, LDA and QDA each performed better in some cases, and worse in others, suggesting that there is not a one-size-fits-all solution. Ultimately, while the first two PCs are the ones plotted here for ease of data presentation, we used the information for the first several PCs even beyond those two in the downstream LDA/QDA analysis.…”

Highly Sensitive Uric Acid Detection Based on a Graphene Chemoresistor and Magnetic Beads

“…As shown in Figure 5 c, the three main peaks of graphene, such as D, G, and 2D peaks, were located near 1350 cm −1 , 1590 cm −1 , and 2700 cm −1 , respectively. The related assignments of spectral peaks to chemical bonds can be found in our previously published works [ 28 , 29 , 30 ]. By comparing the intensities of G and 2D peaks, the I 2D /I G ratio was about 2, and more than 90% of the graphene film was determined as a single layer.…”

Identification of amyloid beta in small extracellular vesicles via Raman spectroscopy

“…Later studies demonstrated the use of Raman spectroscopy for characterization of single extracellular vesicles 39 , as well as clusters of EVs trapped in the laser focus 40 . In addition, recent studies have indicated that Raman spectroscopy can be used for tissue characterization by analyzing the spectral signature of cancer EVs for prostate cancer diagnosis 41,42 , as well as tissue-specific EVs derived from mesenchymal stromal cells 43 and peripheral blood mononuclear cells 44 . Furthermore, urinary EVs from diabetic patients and hyperglycemic endothelial cells 45 have been successfully characterized by Raman spectroscopy.…”

“… 40 In addition, recent studies have indicated that Raman spectroscopy can be used for tissue characterization by analyzing the spectral signature of cancer EVs for prostate cancer diagnosis, 41,42 as well as tissue-specific EVs derived from mesenchymal stromal cells 43 and peripheral blood mononuclear cells. 44 Furthermore, urinary EVs from diabetic patients and hyperglycemic endothelial cells 45 have been successfully characterized by Raman spectroscopy. Immune-capture based single EV Raman spectroscopy 46 has also been reported as a promising approach.…”