Multi-parameter characterization for tear fluid EVs

Extracellular vesicles (EVs) in easily accessible body fluids have emerged as a promising source for liquid biopsy diagnosis. Although the collection of tears can be fast, safe, and noninvasive, the researches on EVs in tear fluid are rare. Additionally, the involvement of the EVs in physiological and pathological processes is still largely unknown. The aim of this study was to analyze and characterize EVs in tear fluid at single-particle level to reveal the population heterogeneity by the Flow NanoAnalyzer. The expression of CD9, CD63, CD81, CD47, CD45, CD24, and EpCAM was assessed via immunofluorescent detection. The EV concentration and size distribution in tear fluid was measured using SSC light detection. It also compared the positive rate and abundance of tissue factor (TF) in tear and saliva EVs, providing theoretical support for further exploration of the function of tear EVs.

Figure 1. Morphology and purity characterization of EVs isolated from unstimulated tears.

                            Figure 2. Concentration analysis and particle size distribution of EVs in tears.           Figure 3. Protein marker phenotyping of EVs isolated by UC from human tears.

Figure.4. Characterization of TF-exposing EVs in tear and saliva.

The purity, size distribution, particle concentration and the expression of eight membrane proteins of tear fluid EVs were analysed using the Flow NanoAnalyzer. Moreover, the presence of high TF expression in tear EVs exhibited strong coagulation activity, providing a new research perspective for ophthalmic studies.

CHINESE J ANAL CHEM, 2021, 48(10), 1305-1314.