1.Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education,Tianjin University of Technology;2.Institute of Medical Equipment,Academy of Military Medical Science,Institute of Medical Support Technology
目的 开发一套新型的应变加载装置，用于贴壁细胞力学生物学研究。方法 该装置基于基底形变加载技术，采用可控制编程器驱动步进器，引起硅橡胶小室变形，实现多单元大应变的细胞加载；研制该装置，检测机械性能；建立硅橡胶小室的三维模型，利用有限元技术对硅橡胶小室进行仿真，分析该小室的应变场均匀性问题；采用该装置对骨髓间充质干细胞加载5%的机械应变，频率为0.5Hz，每天加载2h，持续5天，并在倒置显微镜下观察细胞形态的变化。结果 该装置可对体外三组细胞加载基底实现最大至50%的机械单向应变，并可对加载的频率、拉伸保持时间、应变大小进行方便的调节，具有应变变化范围大、拉压兼具、适用对象广、操作方便、精度高等特点；机械性能表明本实验研制的应变加载装置机械性能可靠，具有良好的可操控性，操作观察方便；利用有限元法对三维硅橡胶小室基底的大变形进行了模拟，结果显示在10%应变范围内，硅橡胶小室底部的均匀应变场面积占比保持在60%以上，保证了细胞受力均匀；骨髓间充质干细胞加载5天后，细胞形态发生明显变化，呈扁平状，排列方向趋于垂直主应变加载方向，与文献报导具有很好的一致性。结论 该装置运行可靠，应变范围宽，频率可调，操作方便，可同时对多组细胞培养基底进行应变加载，为细胞力学生物学研究提供了便利条件。
Objective To design a new strain loading device for researching the mechanical biology of adherent cells. Methods Based on the technology of base deformation loading, the controllable and stepper were designed, and the silastic chambers were loaded and the device was provided to realize the cell loading with multiple units and large strain. The device was developed and its loading function were tested. The three-dimensional models of the silastic chamber were established to simulate the loaded chamber by the finite element technology, the uniformity of the strain field were analyzed. The device applied 5% strain to BMSCs with stretch fre-quency at 0.5Hz for 2 hours a day and lasted 5 days, and an inverted phase con-trast microscope was used to observe the morphology of BMSCs. Results The de-veloped device can provide mechanical strain up to 50% for three groups of cells loading substrates with the advantage of large strain, convenient operation and high precision and it could be used for experiments of tension to cells as well as compression, and the frequency of stretch, the time of stretch and strain magnitude could be conveniently adjusted. The tests showed that the strain loading device for adherent cells in vitro was provided with reliable mechanical function, and the de-vice could be operated and observed easily. The finite element method was used to simulate the large deformation of the three-dimensional silastic chambers, and the results of simulation showed that strain was uniform in the area of 60% at the strain of 10%, it could be ensured that the cells were loaded evenly. After the BMSCs were stretched, the morphology of cells were altered, and the BMSCs were flat shaped, and the direction of arrangement tended to be perpendicular to the loading direction of principal strain, which were in good agreement with the literature reports. Conclusions The device has the advantages of reliable operation, wide strain range, adjustable frequency and convenient operation. It can be used to load multiple cell culture substrates at the same time, which provides convenient conditions for the study on cell mechanobiology.