טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentInna Kviatkovsky
SubjectHigh-Resolution Imaging of Deformed Erythrocytes in
Flow
DepartmentDepartment of Biomedical Engineering
Supervisor Professor Yelin Dvir
Full Thesis textFull thesis text - English Version


Abstract

Due to lack of stiff cytoskeleton and nucleus, erythrocytes (red blood cells) are relatively soft, providing them with unique mechanical properties and ability to flow through vessels smaller than their diameter. Despite the great need to study oxygen transport to tissue in vivo, subcellular-resolution microscopy of erythrocytes in rapid flow remains a challenge, particularly in small vessels that require imaging through the scattering skin layers. In this work, a technique termed spectrally encoded flow cytometry (SEFC) was used to image erythrocytes in flow without exogenous labeling, and to study their unique membrane morphology. A three dimensional reconstruction of the cell membrane morphology was accomplished using a custom-built numerical simulation model for analyzing the fringes patterns formed by the interference between the reflecting surfaces within the confocal imaging plane. Erythrocytes obtained from sickle-cell anemia patients were imaged in vitro while flowing through a flow chamber. By comparing in vitro images of erythrocytes obtained from sickle-cell anemia patients to our numerical model, we have calculated the three-dimensional cell shapes and formulated a new analytical expression that more accurately describes the sickle-cell shapes. Deformed erythrocytes were also evident during in vivo imaging in healthy volunteers, while the cells flow in narrow capillaries. In such narrow vessels, erythrocytes produce images that agree well with established theoretical predictions and with in vitro experimental models. Our results demonstrate SEFC capability to study the three-dimensional morphology of erythrocytes both in vitro and in vivo, and provide a highly accurate tool for studying the physiology and dynamical properties of red blood cells under various conditions.