Electrically shielded dielectric elastomer actuators for the study of the mechanical perturbation of cardiomyocytes

We present the development of a mechanically active bioreactor. Using dielectric elastomer actuators (DEA), we are able to mechanically perturb cell cultures in a controlled environment. With tailored pre-strain and compliant electrodes, it is possible to digitally control the strain state of the cell culture substrate and generate tensile strain exceeding 20%. This bioreactor enables new types of studies of cytomechanics. Specifically, we will use the bioreactor to study cellular mechanisms of cardiac arrhythmias that are related to mechanoelectrical feedback. DEAs require high electric fields to generate physiologically relevant strain levels of 10%. Typically, potentials up to 5 kV are applied to electrodes that are located a few tens of microns from the cells. Resulting electrical fields may adversely affect cell physiology and mask the mechanosensitive response under study. To circumvent this problem, we present a stacked DEA design where the HV-electrode is embedded between grounded electrodes. This design practically eliminates the cells’ exposure to fringe fields. Compared to a two-electrode configuration, it is shown that stray fields can be suppressed by six orders of magnitude. Tests on cardiomyocytes indicate that this layout is sufficient to prevent unwanted electrical triggering of the action potential. The device presented demonstrates the ability to combine electrically sensitive cells with mechanically active DEA bioreactors.