Dr. Chris Ward at the University of Maryland and an expert in single cell measurements, wanted to observe real-time change of cultured cells while under the stress of mechanical stretching. He was using Strex chambers and Siskiyou 7600 XYZ manipulators to perform the stretching motion.
The manipulators have only manual position controls and therefore could not be used to create a repeatable sinusoidal stretching motion. Furthermore, Dr. Ward found he could not observe the stretching cells under high magnification; they would move out of the field of view of the microscope. It is not possible to perfectly align the cell with the center of the Strex chamber and when the chamber is stretched the cells translate across the field of view and disappear.
Dr. Ward, a long-time supporter of Aurora Scientific, approached us to try our 820A Dual XYZ Motion Controller. The 820A provides closed-loop control of Siskiyou 7600 XYZ stages with position feedback and could be used to produce the required sinusoidal motion. A sinusoidal motion function was built into the 820A control software requiring the user to enter frequency, amplitude and number of cycles desired. When executed, this function drives the stages to produce the desired stretching motion. The Assay Stretch function was then added to the software to control the position of the cell during stretching under high magnification. This function superimposes a translation motion on the sinusoidal motion to hold the cell centered in the field of view as the sinusoidal oscillation occurs.
The 820A XYZ Dual Motion Controller was tested with a variety of cultured cells. Dr. Ward found that cell stretching was easy to program and the desired motion effectively produced. As expected, when used with the simple sinusoidal motion function the cells still moved across the field of view. At low magnification this should not be an issue as the cells remain within the field. At high magnification, however, the Assay Stretch function will be required. At this point, experiments using the Assay Stretch function have not been completed but testing at Aurora Scientific indicates that the function should meet the needs of Dr. Ward for samples under high magnification. He was able to integrate the 820A with his own XYZ manipulators and microscope to make measurements that otherwise would be difficult to achieve. Maintaining these cells in the field of view will enable Dr. Ward to integrate real-time fluorescence measurements of proteins activated during muscle cell stretching and their role(s) in disease states.