Poster abstracts
Poster number 13 submitted by James Kim
Separation of the healthy red blood cells for better blood transfusion practices using the intrinsic magnetization of hemoglobin
James Kim (Ohio State University, Department of Chemical and Biomolecular Engineering), Mitchell Weigand (Ohio State University, Department of Chemical and Biomolecular Engineering), Andre F. Palmer (Ohio State University, Department of Chemical and Biomolecular Engineering), Maciej Zborowski (Cleveland Clinic, Department of Biomedical Engineering), Mark H. Yazer (University of Pittsburgh, Department of Pathology), Jeffrey J. Chalmers (Ohio State University, Department of Chemical and Biomolecular Engineering)
Abstract:
In 1936, Pauling observed that human RBCs in different oxygenation state express different magnetization due to the chemical bonding state. This difference in magnetic moment has led many researchers to explore the possibility of magnetically separating the RBCs. In 2017, Chalmers has found that RBCs lose an average of 17% of their hemoglobin (Hb) during ex vivo storage using magnetic characterization method. This study has brought many attentions around the blood community for the need of better blood transfusion practices. In this study, we focus on attempting to find the relationship between the loss of hemoglobin in RBCs and the translocation of phosphatidylserine (PS, a phospholipid commonly used for detecting apoptosis of animal cells) and investigate the feasibility of magnetically separating the apoptotic RBCs from the fresh, healthy RBCs for blood transfusion.
Five expired human RBC units were oxidized and labeled with a marker that would bind to translocated PS, then sorted into four population based on the intensity of the PS-expression using flow cytometer. The sorted samples were then magnetically characterized using the cell tracking velocimetry system (CTV), an analysis system that uses scientific camera and magnetic microfluidic channel to quantify the magnetic susceptibility of cells. Then, a microfluidic magnetic separation system has been numerically modelled using a combination of commercial computational fluid dynamics software and custom algorithm that uses the CTV data, and was further used to calculate the trajectory of the paramagnetic RBCs.
The CTV data were further analyzed to calculate the Hb concentration, and high PS expressing sub-population was shown to be low in Hb compared to the other sub-populations. The numerical model has also shown that different magnetic moment of entities can lead to different location of the deposition location, implying that high PS-expressing (damaged) RBCs and PS-negative (healthy) RBCs have different magnetic moment that could be used to magnetically separate healthy and damaged RBCs.
The average blood transfusion efficiency is known to be about 75%, which can lead to serious clinical effects. With the improvement in transfusion practices through these findings in research, more effective blood transfusion will be possible.
References:
Zborowski, Maciej, et al. "Red blood cell magnetophoresis." Biophysical journal 84.4 (2003): 2638-2645.
Chalmers, J. J., et al. "Femtogram resolution of iron content on a per cell basis: ex vivo storage of human red blood cells leads to loss of hemoglobin." Analytical chemistry 89.6 (2017): 3702-3709.
Keywords: red blood cells, magnetic separation, hemoglobin concentration