A METHOD FOR INDUCING EQUI-BIAXIAL AND UNIFORM STRAINS IN ELASTOMERICMEMBRANES USED AS CELL SUBSTRATES

A device is described which is designed to bring about uniform and equ i-biaxial strains of 0.04-0.4% on a circular elastomeric sheet upon wh ich cells are grown in a monolayer. Strain measurements at six differe nt radii of the well provide evidence of the uniformity of the strain field over the 2.54 cm diameter of the well with a mean strain of 0.15 % and a standard deviation of 0.01% strain. Major advantages of the sy stem over those previously described are that(l) the substrate remains in the same plane throughout the application of stretch, (2) the devi ce is designed to provide a state of uniform equi-biaxial strain to th e entire substrate of the cells and (3) all cells 'see' the same strai n field, no matter what their orientation. This allows for real-time o ptical monitoring of the cells throughout the stretching cycle of the cell substrate. In this way, changes in the cell membrane, cell nucleu s, cytoskeleton and in fluorescently labelled calcium can be monitored microscopically during application of an equi-biaxial mechanical stre tch.