Mechanical Property Change of Red Blood Cell Membrane under Photosensitizer Mediated Oxidative Stress of CIS Porphyrin

Various cytoskeletal networks have been investigated to understand the cell mechanics because it can directly apply for therapeutic researches of immune or cancer disease. However, due to a lack of sufficient signal-transduction measurement techniques, even for the well-studied red blood cell (RBC), the relationships between the cytoskeleton physiology and mechanical properties of the cell membrane – i.e., “signaling” – are still not well understood. Here, we applied a newly designed micropipette manipulation technique to make dynamic membrane elasticity measurements in the presence of a therapeutic photosensitizer-mediated oxidant, cis-porphyrin. We found that the shear modulus of the RBC was dynamically changed from 6.7 ± 0.5 x 10−6 N/m (absence of the porphyrin) to a non-measureable or plastic-like behavior value (presence of 0.05 μM porphyrin and irradiation) with the degree of oxidative stress controlled by the irradiation. We also found that the porphyrin oxidative stress could induce unique morphological change before hemolysis of the RBC. We hypothesize that dynamical cytoskeletal network reformation with oxidative stress could cause these behaviors. Therefore, to visualize the network proteins, we also applied the techniques of Stimulated Emission Depletion (STED) microscopy. We consider that this further characterization of the mechanical properties of the RBC membrane will help to understand more complicated cytoskeletal network of immune, cancer or even neuron cells for therapeutic development in the future. More details will be shown at the meeting.