Year: 2018
Type: dissertation
Abstract: The mechanical properties of red blood cells (RBCs) have been proven to play important roles in the regulation of various biological activities and have shown clinical significance. During the past few decades, a number of research studies have been conducted to understand the relationship between RBC mechanical properties and diseases. The work described in this thesis focuses on characterizing mechanical properties of RBCs from sickle cell trait (SCT) carriers and the degradation/recovery of stored RBCs in transfusion medicine. The mechanical properties and changes of SCT RBCs under deoxygenated and acidic environments, two typical conditions present in the circulation of athletes undertaking strenuous exercise, were measured. The results revealed that SCT RBCs are inherently stiffer than RBCs from non-SCT healthy subjects, and a lower pH further stiffens the SCT cells. Furthermore, at both normal and low pH levels, deoxygenation was found to cause no change of SCT RBCs stiffness. In transfusion medicine, compromised RBC deformability can lower the transfusion efficiency or intensify transfusion complications. This thesis reports microfluidic mechanical measurement of stored RBCs under the physiological deformation mode. The results revealed that the effective stiffness of RBCs increases over the storage process. RBCs stored for one week already started to show significantly higher stiffness than fresh RBCs, and stored RBC stiffness degraded faster in the last three weeks than in the first three weeks. Although the stiffness of stored RBCs degrades over the storage process, whether the stiffness of stored RBCs can be reversed after transfusion remains unknown. A microfluidic platform was used in this thesis to measure the evolution of RBC stiffness recovery under in vivo-like conditions. RBCs stored up to 6 weeks (42 days) in the blood bank were measured, revealing that the degraded stiffness of RBCs over the storage process can be recovered in human serum within 120 minutes. However, the recovered stiffness of older RBCs (stored for 4-6 weeks) is still 1.6 – 2.1 times higher than that of fresh RBCs. Furthermore, ATP, which provides energy to keep RBC membrane mechanically functional, was also measured. The ATP concentration in stored RBCs was found to increase in human serum.
Source: TSpace (University of Toronto)
Author: Zhensong Xu
Language: English
Subfield: Hematology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W3161075108