An array of 100 μm × 100 μm dielectric elastomer actuators with 80% strain for tissue engineering applications

Biological cells modulate their behavior, express genes, proliferate or differentiate in response to mechanical strains ranging from 1% to 20%. There currently exists no technique to apply strain to many targeted individual cells in a larger culture in order to perform parallelized high throughput testing. Dielectric elastomer actuators (DEAs) are compliant devices capable of generating large percentage strains with sub-second response time, ideally suited by their compliance for cell manipulation. We report an array of 100 μm × 100 μm DEAs reaching up to 80% in-plane strain at an electric field of 240 V/μm. The miniaturized DEAs are made by patterning 100 μm wide compliant ion-implanted gold electrodes on both sides of a 30 μm thick polydimethylsiloxane (PDMS) membrane. We report the important effect of uniaxial prestretch of the membrane on the microactuators' performance; the largest strain is achieved by prestretching uniaxially by 175%. Each actuator is intended to have a single cell adhered to it in order to periodically stretch the cells to study the effect of mechanical stimulation on its biochemical responses. To avoid short-circuiting all the top electrodes by the conductive saline cell growth medium, a 20 μm thick biocompatible PDMS layer is bonded on the actuators. In this configuration, 37% strain is achieved at 3.6 kV with sub-second response. This device can be used as a high throughput single cell stretcher to apply relevant biological periodic strains to individual cells in a single experiment.