ABSTRACT
Human red blood cells (RBCs) are essential for transportation of oxygen and carbon dioxide for human bodies. The mechanical properties of cells are crucial to the exercise of normal cellular functions. Abnormity of cell mechanics may cause disorders. In this chapter, the biomechanical properties of human RBCs in hypotonic conditions are investigated using robotic manipulation technology with optical tweezers to understand the correlation between cell mechanics and osmotic environments. Optical traps serve as end-effectors to manipulate microbeads attached to the cell surface. The cell is stretched by progressively increasing the distance between the bead and the binding site, where the induced deformation responses are recorded for analysis. To extract the 148mechanical 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.
