Design of a microfabricated cell straining device for investigating cellular response to finite mechanical strains

A methodology is presented for the design of a microfabricated blister-type device to examine the cellular response of isolated cells and multi-cellular aggregates to finite mechanical strains (1-5%):. The proposed device utilizes microfabrication technologies that incorporate the bonding, transfer, and assembly of thin (3 /spl mu/m < thickness < 100 /spl mu/m) elastic membranes onto rigid substrates with a circular hole or array of circular holes in the formation of diaphragm structures. An analysis of membrane deformations and strain fields of macro- and micro-scale polydimethylsiloxane (PDMS) diaphragm, blister-type devices demonstrates that microfabricated diaphragms can achieve finite strains corresponding to smaller axial displacements than those required for identical strains in macro-scale devices. Smaller axial displacements may decrease the confounding shear loading of the cell culture by the overlying nutrient medium. Additionally, it is shown that the uniform residual stress of a microfabricated diaphragm can be experimentally determined and utilized for more precise control of the incremental finite strains imposed on the diaphragm. Thus, microfabricated blister-type cell straining devices may potentially enhance future quantitative investigations of dynamic mechanically stimulated cell culture.