講演情報
[11a-B31-7]Simultaneous determination of effective cell elasticity and internal pressure in adherent animal cells using AFM and elastic shell theory
〇(D)Emi Kurnia Sari1, Yuka Tsuri1,2, Naomi Tanga1,3, Yoichiroh Hosokawa1,2,3 (1.Div.Mat.Sci., NAIST, 2.MLC, NAIST, 3.CDG, NAIST)
キーワード：
cultured animal cell、nano-indentation、force-curve evaluation
Quantitative information of cell mechanical parameters such as stiffness and internal pressure is required to understand cell morphology, physiology and pathology. We have developed a new method for plant cells that combines atomic force microscopy (AFM) and elastic shell theory (EST) to determine these parameters simultaneously. In this method, the cell wall is treated as a “shell” enclosing the cell, and AFM topographic images together with a liner response of force-indentation curves are analyzed to estimate the cell wall elastic modulus (E) and internal pressure (P). In this study, we evaluated the applicability of this method to adherent animal cells, using Madin-Darby canine kidney (MDCK), mouse fibroblast (NIH3T3), and human brain tumor (U87) cell lines. One day after culture, the cells were probed using an AFM cantilever with a spherical tip (CP-CONT-SiO-C, radius 3.3 µm). After calibration by the non-contact thermal noise method, the spring constant was approximately 0.2 N/m. The resulting topographic images, force-indentation curves and corresponding differential curves are shown in Fig 1. A linear response at deep indentation was found only in NIH3T3 cells, indicating that EST is applicable. Based on EST, the E and P for four NIH3T3 cells were estimated to be 0.5 ± 0.3 MPa and 7 ± 3 kPa, respectively. We found that NIH3T3 cells possess actin filaments with higher dencity than MDCK and U87 cells by fluorescence observation. These results suggest that a dence network actine filament integrates with the cell membrane, forming a membrane-cortex complex that acts as a shell-like structure of the cell. Accordingly, here, E represents the effective in-plane elastic modulus of the cell membrane-cortex complex and P represents the effective intracellular pressure. Simultaneous estimation of E and P from AFM using EST offers an alternative method for evaluating the mechanical properties of charactaristic adherent animal cells.