Study on the Dynamic Properties of Living-Cells from the viewpoint of Intelligent Vibration-Reducible Structure

生物基本上是由细胞组成的，细胞可以适应环境，它们聚集在一起寻找同类细胞，排除对它们不利的刺激，保持最佳的生命保存状态。尽管细胞在生物学、医学、生物化学等领域已经得到了广泛的应用，但当它们作为微机械的原型时，可能会引起机械工程师的注意。但是，关于细胞的机械性质几乎没有研究。该项目致力于揭示活细胞的力学特性，并将其应用于构建更智能的结构。作为活细胞，骨相关细胞被用于本研究中，骨细胞具有对周围力学条件的适应性。成骨细胞是骨形成的主要细胞，研究发现，成骨细胞对机械振动有反应，并改变细胞增殖和骨生成量。为了找到有效的刺激 ...更多信息 在成骨过程中，有必要从机械工程的角度了解细胞的力学特性，如弹性或粘性。在骨细胞的情况下，重要的是要了解在粘附条件下的机械性能，因为它们附着在骨基质的表面上。在这项研究中，我测量动态粘弹性培养成骨细胞，MC 3 T3-E1，在粘附条件下，通过施加正弦变形。利用这些实验结果，我们推导出了Voigt粘弹性模型，并确定了各个参数的值。对骨骼的机械刺激会影响骨生成，如失重状态下宇航员骨量减少和超声设备修复骨折。骨细胞在细胞水平上通过形态学和代谢对机械刺激进行感知和反应。从机械振动的角度来看，骨细胞根据机械刺激及其力学特性而变形。据报道，细胞的粘弹性是通过拉伸和蠕变试验来测量的，并且在结构动力学意义上可能存在细胞的固有频率和非线性。提示机械刺激对骨细胞成骨的影响存在有效的频率和幅度。在这项研究中，正弦惯性力施加到培养的成骨细胞，MC 3 T3-E1，和频率和加速度振幅的机械振动对细胞的细胞增殖，骨基质生成和碱性磷酸酶（ALP）基因表达的影响进行了研究。少

Living creatures are fundamentally composed of cells, which may adapt to their environment; they get together finding the same kind of cells, exclude inconvenient stimulus to them, and keep the best condition for life conservation. Though the cells have been treated in biology, medical science, or bio-chemistry, they may be paid attention by mechanical engineers when they are regarded as a prototype of micro-machine. But, almost nothing has been studied as for the mechanical properties of cells. This project is concentrated to reveal mechanical properties of living cells and they are applied to construct more intelligent structures. As living cells, a bone related cell are used in this study.Bone cells have adaptability to the surrounding mechanical condition. Osteoblasts, which are responsible for bone formation, were reported that they responded to mechanical vibration and changed the cell proliferation and the amount of generated bone mass. In order to find the effective stimulation … More on osteogenesis, it is necessary to understand the mechanical properties such as elasticity or viscosity of the cells in the view of mechanical engineering. In the case of bone cells, it is important to understand the mechanical properties under adhesive condition because they attach on surfaces of bone matrices. In this study, I measured dynamic viscoelasticity of a cultured osteoblast, MC3T3-E1, under adhesive condition by applying sinusoidal deformation. Using these experimental results, we derived Voigt model for viscoelasticity and identified the value of each parameter.Next, the effect of mechanical stimulation was evaluated. Mechanical stimulation to bones affects osteogenesis such as decrease of bone mass of astronauts under zero gravity and fracture repair with ultrasound devices. Bone cells have been reported to sense and response to mechanical stimulation at cellular level morphologically and metabolically. In the view of mechanical vibrations, bone cells are deformed according to mechanical stimulation and their mechanical characteristics. It was reported that viscoelasticity of cells was measured using tensile and creep tests and that there was likely natural frequency and nonlinearity of cells in the sense of structural dynamics. It suggests that there is effective frequency and amplitude of mechanical stimulation on osteogenesis by bone cells. In this study, sinusoidal inertia force was applied to cultured osteoblasts, MC3T3-E1, and effects of frequency and acceleration amplitude of mechanical vibration on the cells were investigated in respect of the cell proliferation, bone matrix generation and alkaline phosphatase (ALP) gene expression. Less