Fabrication of a pneumatically-driven tensile stimulator

This paper introduces a pneumatically-driven tensile stimulator for investigating the effect of mechanical strain on intracellular calcium expression in MG-63 cell (human osteoblast-like bone cell). An optically transparent micro-tensile stimulator array, consisting of deformable diaphragms and micro-fluidic channels, was fabricated with polydimethylsiloxane (PDMS) and a glass substrate. A strain gradient generated by a three-dimensional dome-shaped deformation of the circular diaphragm was applied to live cells seeded on the deformable diaphragm of the pneumatic stimulator. During the operation, intracellular calcium responses were measured using a laser-scanning microscope. Based on the temporal responses of the fluorescent intensities, we discovered that the periods of the measured calcium expressions of cells in different strain regions were well matched with the applied signal waveforms of the external compressed air. Moreover, the magnitude of the intensities in a cell was proportional to the magnitude of the mechanical strain. We were able to conclude that the release/uptake of intracellular calcium in the endoplasmic reticulum may be activated by, and sensitive to the applied strain. (C) 2012 Elsevier B.V. All rights reserved.