Biosensing of Red Blood Cell-derived Extracellular Vesicles with the advanced Bright-Field light Optical Polarization Microscopy

Background: Red blood cell (RBC)-derived extracellular vesicles (EVs) are recognized a sensitive predictive biomarker of cardiovascular risk, which allow distinguishing vulnerable population from healthy and also physiological aging from premature one. Current known methods of determination of RBC-EVs are based on several principles including flow cytometry, culture methods and various visualization techniques (surface plasmon resonance and computer tomography / magnetic resonance imaging), and various types of microscopy, i.g. high sensitive optical coherent microscopy (hs-OCM), atomic microscopy, fluorescent microscopy. However, there are some limitations and broad variabilities in cost of mentioned above methods of EV-determination. The aim of the study was to compare a capture ability of conventional hs-OCM and advanced bright-field light optical polarization microscopy in detection and measurement of the RBC-EVs. Methods: The study was retrospectively evolved 26 patients with established stable coronary artery disease who were examined between May 2015 and November 2016. The samples of whole blood were collected before ingestion of the meal at room temperature at the morning with powder-free gloves. We used a conventional hs-OCM and advanced bright-field light optical polarization microscopy with improved capture features. Conventional hs-OCM and advanced bright-field light optical polarization microscopy was performed with an Olympus？？ BH-2 microscope (Olympus, Japan). The whole sample was scanned with the Zeiss 10x objective (100x). The monochromatic laser was used to emanation of light with an appropriate wavelength. It has been identified number and relative size distribution of RBC-EVs with further analysis of morphology using original soft. Results: hs-OCM images supported by yellow-green light allow visualizing cell-free EVs without possibilities for assay their structure and measurement of their number. In contrast, ultraviolet light-enhanced hs-OCM is able to improve capture features of RBC-EVs including their number, diameter and roughly structure. Using advanced bright-field light optical polarization microscopy associated with original soft allows distinguishing low-contrasted objects in details when we used monochromatic light with ？？=370+30 nm with further math modelling. Conclusions: the advanced bright-field light optical polarization microscopy allows detecting clinically relevant properties of EV in wide ranges and could be determined a new much promising technique, which allows assaying EV in low cost