Three-Motorized-Stage Cyclic Stretching System for Cell Monitoring Based on Chamber Local Displacement Waveforms

Researchers have developed a cell stretching device to mimic the in vivo mechanical environment in vitro in order to investigate cell mechanotransduction. Cyclic stretch is involved in lengthening and relaxation phases. Cells may respond to mechanical stimulation rapidly within a few seconds, and sudden disruption of cell cytoskeletons may also occur at any point in any phase of cyclic stretch. However, until now, no research has been done to establish a method of collecting cell images at the two phases of cyclic stretch. Because image processing is time-consuming, it is difficult to adjust focus and collect high-resolution images simultaneously at the two phases during the process. In this study, a three-motorized-stage system was developed to meet the requirements. The results demonstrated that linear compensation is effective for cell imaging, and it is applicable to have a feed-forward control method without image processing. A method was then developed to determine the maximum displacement of the target in the horizontal and vertical directions, and the linear compensation waveforms were designed using the C program automatically and immediately before stretching. Further, the cyclic stretch was applied to cells using the three motorized stages, and clear phase-contrast cell imaging (30 fps) were obtained almost at any point in time. Detailed cell changes such as sudden disruption of cell–cell junctions, not only long-term cell response, were observed. Therefore, our study established a methodology to greatly improve the time resolution of imaging of cyclic stretch for the research of detailed cellular mechanotransduction.