Cells are constantly exposed to a variety of mechanical perturbations and their response to these stimuli plays a vital role in their proper functioning. Here, we present a micro-mechanical device for providing a mechanical stimulus to cells cultured on it and observing the change in the deformation of the nucleus of the cell. Our device has the provision to stretch, in-situ, single cells by different amounts through a single actuation based on their points of adhesion on the device. The device consists of folded beams that deform as in an accordion, which is actuated using a probe attached to an XYZ positioner. The device is microfabricated on glass coverslips using SU-8, which is transparent and allows for the visual measurement of the nucleus through high-magnification imaging during stretching. Many devices can be accommodated on a single coverslip and can be actuated independently. Growing cells on the device do not need any specialized technique: it is easily achieved by seeding cells at low density directly on the coverslip. Furthermore, the single-mask microfabrication process developed for the mechanism permits a range of stiffness by changing only one mask or the thickness of the structural layer. We demonstrate the utility of the device by culturing NIH 3T3 fibroblasts on the devices, stretching them in-situ, and measuring the deformation of their nuclei using fluorescence imaging.
Publication is available here.
We are further working to estimate the traction force exerted by cells from the deformation of the mechanism. See the video below.