Design and Fabrication of a Dielectric Elastomer Actuator for Organ-on-Chips Platforms

Abstract

Cell behavior in vitro can be regulated by mechanical stimulation. Cytostretch is an Organ-on-Chip (OOC) platform that allows cyclic stretching tissue in culture. Its pneumatic actuation can hinder it from microfluidic systems integration. A dielectric elastomer actuator (DEA) was developed and fabricated in this thesis for Cytostretch as an alternative actuation method. The DEA consists of a suspended polymer membrane sandwiched between electrodes, which can induce out-of-plane motion when a voltage is applied. The functionality of the design was proved in numerical analysis. A complete process flow was developed and partly implemented for the wafer-scale microfabrication of this innovative actuator. The top electrodes of the device were fabricated by depositing and patterning titanium nitride with stress buffering layers. The quality of the electrodes was examined and wrinkles were found at corners of certain etching patterns. The angle of the corner and spacing between corners were proposed to be two factors influencing the wrinkle formation. This work paves the way to the successful integration of DEAs for mechanical stimulation of cell tissues within OOC platforms.