Fabrication of Poly-Pyrrole Membrane Actuator for Cell Stimulation

Micro-actuators are used for mechanical stimulation of cultured cells in regenerative medicine and are critical components of biosensors. In this study, electrochemical polymerization is utilized to fabricate a film of poly-pyrrole (PPy) with a thickness of 10 μm. This film is peeled off from a working electrode substrate and subsequently laminated with a polydimethylsiloxane (PDMS) membrane containing holes of diameter of 5 mm. The assembled PPy film forms a membrane of PPy that can be used as a micro-actuator. This membrane is deflected upward via the application of voltages of −0.2, −0.4, −0.6, −0.8, and −1.0 V for 120 s in either NaDBS solution or cell culture solution. The primary response was an expansion in the in-plane direction with the absorption of ions in the electrolyte solution. The deflection increases with the duration of the applied voltage. Moreover, the maximum deflection that increases with the applied voltage reaches 540 μm at −1.0 V in the NaDBS solution. In the cell culture solution, the maximum deflection is approximately 400 μm for an applied voltage of −1.0 V. When the PPy membrane actuator was used in the culture solution, the time constant was 20 s to reach 63.2% of the maximum deflection. During operation, a voltage with a rectangular form and a period of 40 s was periodically applied. The operation of the PPy membrane actuator was repeated 90 times or more, although the deflection of the membrane had slight attenuation during the cycle of applied voltage. The PPy membrane exhibited adequate adhesiveness for cultured C2C12 cells. They adhered to the PPy surface and stretching of their pseudopods was observed. These cells are additionally cultured on the PPy membrane actuator. When a voltage is applied, the membrane actuator is operable while supporting cultured C2C12 cells. These cells are mechanically and electrically stimulated on the membrane that functions as a cell stimulation device.