Silki Arora

Volume and Morphological Changes in Red Blood Cells with Pressure Probed by Optical Imaging In-Situ

Functional properties of living cells depend on the thermodynamic variables temperature and pressure. A unique tool to investigate volume effects on structure and metabolism of the cell is pressure perturbation. We employ a setup that allows visualizing individual live cells at variable pressure in real time. We present measurements of volume changes in red blood cells (RBC) over the pressure range from 0.1 to 200 MPa. Up to a pressure of 35 MPa the size of a healthy erythrocyte remains constant. Over the pressure range from 35 MPa to 200 MPa the lateral diameter decreases linearly and reversibly with a slope of 0.015 micron / MPa, while there are no significant alterations in shape. The RBC deformability is discussed in terms of the cell membrane elasticity and effects of the cytoskeletal network. Our experiments are extended to RBCs infected with the malaria parasite Plasmodium falciparum. Here, we observe clear differences in the deformability with pressure and between the compression and decompression curves.