Arrays of EAP micro-actuators for single-cell stretching applications

Mechanical stimuli are critical for the development and maintenance of most tissues such as muscles, cartilage, bones and blood vessels. The commercially available cell culture systems replicating the in vivo environment are typically based on simple membrane cell-stretching equipment, which can only measure the average response of large colonies of cells over areas of greater than one cm2. We present here the conceptual design and the complete fabrication process of an array of 128 Electro-Active Polymer (EAP) micro-actuators which are uni-axially stretched and hence used to impose unidirectional strain on single cells, make it feasible to do experiments on the cytomechanics of individual cells. The Finite Element Method is employed to study the effect of different design parameters on achievable strain, leading to the optimized design. Compliant gold electrodes are deposited by low-energy ion implantation on both sides of a PDMS membrane, as this technique allows making electrodes that support large strain with minimal stiffening of the elastomer. The membrane is bonded to a rigid support, leading to an array of 100×100 μm2 EAP actuators.