Controllable Dynamic Mechanical Cell Stimulation using Magnetically Actuated Artificial Cilia.

Dynamic mechanical stimulation plays an important role in determining the function and health of cells and tissues, and it is therefore highly relevant to study the real-time response of cells to time-dependent forces. We introduce a platform for providing controllable dynamic mechanical stimulation to single cells, suitable for investigating large cell populations and enabling live cell imaging, and we present proof-of-principle experiments that demonstrate the platform's capabilities. Cells are cultured on a hydrogel surface with magnetic artificial cilia made from a magnetic elastomer using a tailored micromolding process. The cilia are actuated with an electromagnet integrated with an in-incubator fluorescent microscope. We show that cells attach to the cilia and exhibit widely different morphologies than cells on flat surfaces. Cellular forces involved can be estimated by measuring cilia deflection. We demonstrate that cells can be exposed to continuous dynamic forces by cilia actuation and that their response can be monitored by real-time observation of Yes-Associated Protein (YAP). These experiments indicate rare events of mechanotransduction due to cilia actuation, but the low response prohibits drawing final conclusions about the biological response. Our artificial cilia-based platform offers new opportunities for studying mechanical cell stimulation in real time and understanding dynamic mechanotransduction.