| Project/Area Number |
17200030
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | Tohoku University |
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Principal Investigator |
SATO Masaaki Tohoku University, Graduate School of Engineering, Professor (30111371)
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| Co-Investigator(Kenkyū-buntansha) |
OHASHI Toshiro Tohoku University, Graduate School of Engineering, Associate Professor (30270812)
DEGUCHI Shinji Tohoku University, Graduate School of Engineering, Associate Professor (30379713)
SAKAMOTO Naoya Tohoku University, Graduate School of Engineering, Assistant Professor (20361115)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥46,150,000 (Direct Cost: ¥35,500,000、Indirect Cost: ¥10,650,000)
Fiscal Year 2007: ¥9,620,000 (Direct Cost: ¥7,400,000、Indirect Cost: ¥2,220,000)
Fiscal Year 2006: ¥9,490,000 (Direct Cost: ¥7,300,000、Indirect Cost: ¥2,190,000)
Fiscal Year 2005: ¥27,040,000 (Direct Cost: ¥20,800,000、Indirect Cost: ¥6,240,000)
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| Keywords | Vascular endothelial cells / Vascular smooth muscle cells / Intercellular mechanical balance / Stress fiber / Micropost / Actin dynamics / 局所力学刺激 / 内皮細胞 / 粘弾性特性 / マイクロアレイ / 細胞核 / 平滑筋細胞 / アクチンフィラメント / ひずみ速度依存性 |
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| Research Abstract |
1) Evaluation of mechanical property of stress fibers
Mechanical properties of stress fibers extracted from smooth muscle cells (SMCs) and endothelial cells (ECs) were measured with a microneedle-based tensile test system developed in this study. Strain-induced stiffening was observed in the force-strain curve. We also found that the extracted SFs shortened to approximately 80% of the original length after they were dislodged from the substrate, suggesting that SFs had preexisting strain in the cytoplasm. The force required for stretching the single SFs from the zero-stress length back to the original length was approximately 10 nN for SMCs and 4.1 nN for ECs.
2) Measurement of traction forces of cells using microfabricated micropost arrays
A mold of silicon substrates with arrays of micro-needle-like posts (3μm in diameter, 10μm in height, and 8μm intervals) was fabricated to estimate cellular traction forces using microfabrication techniques. SMCs spreading on the substrates produced deflection of the posts and was associated with organization of stress fibers of actin filaments. Traction forces varied considerably among cells, showing an average of approximately 12 nN.
3) Cyclic stretch test with microsubstrates
We applied cyclic stretch to ECs using a microstructured substrate with arrays of micropost, on which cells were selectively stretched between FAs but FA-substrate contact area were hardly stretched. After exposure ECs to cyclic stretch for 3h, cells on both a flat and the micropost substrates aligned perpendicular to the direction of stretch. Stress fibers oriented about 60° to the stretch direction for the flat substrate at 3h, while stress fibers on the micropost substrate oriented approximately 90° to the stretch direction after 6h stretching. These results suggest that strain in FA-substrate contact area may have impact on rates of reorienation of stress fibers in ECs in response to cyclic stretch.
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