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Biologically Inspired Robotics
mechanical properties from the obtained force–deformation relationship, a cell mechanical model is developed from our previous work. This
model is based on membrane theory and adopts a hyperelastic material
to represent the deformation behavior of RBC membranes. By fitting the
modeling results to the experimental data, the area compressibility modulus and elastic shear modulus are characterized as 0.29 ± 0.05 N/m and
6.5 ± 1.0 μN/m, respectively, which are less than the reported results of
natural RBCs in isotonic conditions. This study indicates that hypotonic
stress has a significant effect on the biomechanical properties of human
RBCs, providing insight into the pathology of some human diseases and
disease therapy.
8.1 Introduction
Human red blood cells (RBCs) are responsible for transportation of oxygen
and carbon dioxide, which are crucial for maintaining normal physiological functions of human bodies. It is well known that RBCs have the ability
to withstand large passive deformation when traversing narrow capillaries
during microcirculation. An RBC mainly includes a liquid drop (hemoglobin) and a biomembrane, in which a lipid bilayer membrane is attached to a
two-dimensional cytoskeletal network through some transmembrane proteins (Mohandas and Gallagher 2008). Compared to the biomembrane, the
resistance of the inner fluid to stress is small and negligible. The deformability of human RBCs is thus dominated by the mechanical properties of
biomembranes.
Cell mechanics is essential in maintenance and regulation of the physiological functions of biological cells. Abnormity of cell mechanics, especially
biomechanical properties, may reflect microstructural alterations of the cytoskeleton and may lead to some disorders. Therefore, cell mechanics of human
RBCs has received considerable attention in recent years. Accumulating evidence has reported that alterations of the mechanical properties of RBCs may
be associated with the onset and progression of some diseases. For example,
mechanical properties of oxygenated RBCs in sickle cell disease are significantly different from those of healthy RBCs (Nash, Johnson, and Meiselman
1984). RBCs parasitized by malaria virus, namely, Plasmodium falciparum,
become rigid and poorly deformable and show abnormal circulatory behavior (Glenister et al. 2002; Shelby et al. 2003; Suwanarusk et al. 2004). The shear
modulus of these infected RBCs was found to increase up to tenfold during
parasite development (Suresh et al. 2005). Additionally, the cell mechanics of
RBCs is related to some other disorders, such as diabetes mellitus (Tsukada
et al. 2001), sepsis (Baskurt, Gelmont, and Meiseliman 1998), and chronic
renal failure (Meier et al. 1991).
Biologically Inspired Robotics
mechanical properties from the obtained force–deformation relationship, a cell mechanical model is developed from our previous work. This
model is based on membrane theory and adopts a hyperelastic material
to represent the deformation behavior of RBC membranes. By fitting the
modeling results to the experimental data, the area compressibility modulus and elastic shear modulus are characterized as 0.29 ± 0.05 N/m and
6.5 ± 1.0 μN/m, respectively, which are less than the reported results of
natural RBCs in isotonic conditions. This study indicates that hypotonic
stress has a significant effect on the biomechanical properties of human
RBCs, providing insight into the pathology of some human diseases and
disease therapy.
8.1 Introduction
Human red blood cells (RBCs) are responsible for transportation of oxygen
and carbon dioxide, which are crucial for maintaining normal physiological functions of human bodies. It is well known that RBCs have the ability
to withstand large passive deformation when traversing narrow capillaries
during microcirculation. An RBC mainly includes a liquid drop (hemoglobin) and a biomembrane, in which a lipid bilayer membrane is attached to a
two-dimensional cytoskeletal network through some transmembrane proteins (Mohandas and Gallagher 2008). Compared to the biomembrane, the
resistance of the inner fluid to stress is small and negligible. The deformability of human RBCs is thus dominated by the mechanical properties of
biomembranes.
Cell mechanics is essential in maintenance and regulation of the physiological functions of biological cells. Abnormity of cell mechanics, especially
biomechanical properties, may reflect microstructural alterations of the cytoskeleton and may lead to some disorders. Therefore, cell mechanics of human
RBCs has received considerable attention in recent years. Accumulating evidence has reported that alterations of the mechanical properties of RBCs may
be associated with the onset and progression of some diseases. For example,
mechanical properties of oxygenated RBCs in sickle cell disease are significantly different from those of healthy RBCs (Nash, Johnson, and Meiselman
1984). RBCs parasitized by malaria virus, namely, Plasmodium falciparum,
become rigid and poorly deformable and show abnormal circulatory behavior (Glenister et al. 2002; Shelby et al. 2003; Suwanarusk et al. 2004). The shear
modulus of these infected RBCs was found to increase up to tenfold during
parasite development (Suresh et al. 2005). Additionally, the cell mechanics of
RBCs is related to some other disorders, such as diabetes mellitus (Tsukada
et al. 2001), sepsis (Baskurt, Gelmont, and Meiseliman 1998), and chronic
renal failure (Meier et al. 1991).