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.

1. [1] N. Huebsch, “Translational mechanobiology: Designing synthetic hydrogel matrices for improved in vitro models and cell-based therapies,” Acta. Biomater, Vol.94, pp. 97-111, 2019.
2. [2] A. Kaneko, Y. Miyazaki, and T. Goto, “Transfer-Print of CNTs and its Application to Cell Scaffold,” Int. J. Automation Technol., Vol.11, No.6, pp. 941-946, 2017.
3. [3] A. Kaneko and I. Takeda, “Textured Surface of Self-Assembled Particles as a Scaffold for Selective Cell Adhesion and Growth,” Int. J. Automation Technol., Vol.10, No.1, pp. 62-68, 2016.
4. [4] Y. Kurashima, S. Miyata, and J. Komotori, “Effect of Cooling Stimulus on Collection Efficiency of Calf Chondrocytes Cultivated on Metal Surface,” Int. J. Automation Technol., Vol.11, No.6, pp. 925-931. 2017.
5. [5] H. Fujie, K. Oya, Y. Tani, K. Suzuki, and N. Nakamura, “Stem Cell-Based Self-Assembled Tissues Cultured on a Nano-Periodic-Structured Surface Patterned Using Femtosecond Lase Processing,” Int. J. Automation Technol., Vol.10, No.1, pp. 55-61, 2016.
6. [6] N. Inomata, M. Toda, and T. Ono, “Microfabricated Temperature-Senseing Devices Using a Microfluidic Chip for Biological Applications,” Int. J. Automation Technol., Vol.12, No.1, pp. 15-23, 2018.
7. [7] H. Ashiba, “V-Trench Biosensor: Microfluidic Plasmonic Biosenseing Platform,” Int. J. Automation Technol., Vol.12, No.1, pp. 73-78, 2018.
8. [8] T. Niioka and Y. Hanada, “Surface Microfabrication of Conventional Glass Using Femtosecond Laser for Microfluidic Applications,” Int. J. Automation Technol., Vol.11, No.6, pp. 879-882, 2017.
9. [9] X. Ouyang, Y. Xie, and G. Wang, “Mechanical stimulation promotes the proliferation and the cartilage phenotype of mesenchymal stem cells and chondrocytes co-cultured in vitro,” Biomed. Pharmacother., Vol.117, 109146, 2019.
10. [10] F. Boccafoschi, M. Bosetti, S. Gatti, and M. Cannas, “Dynamic Fibroblast Cultures : Response to Mechanical Stretching,” Cell Adhes Migrat., Vol.1, pp. 124-128, 2007.
11. [11] Y. Kamotani, T. Bersano-Begey, N. Kato, Y. Tung, D. Huh, J. W. Song, and S. Takayama, “Individually programmable cell stretching microwell arrays actuated by a Braille display,” Biomaterials, Vol.29, pp. 2646-2655, 2008.
12. [12] Q. Yu and M. Li, “Effects of transient receptor potential canonical 1 (TRPC1) on the mechanical stretch-induced expression of airway remodeling-associated factors in human bronchial epithelioid cells,” J. Biomech., Vol.51, pp. 89-96, 2017.
13. [13] C. S. Simmons, J. Y. Sim, P. Baechtold, A. Gonzalez, C. Chung, N. Borghi, and B. L. Pruitt, “Integrated strain array for cellular mechanobiology studies,” J. Micromech. Microeng., Vol.21, pp. 1-10, 2011.
14. [14] S. V. Ebadi, D. Semnani, H. Fashandi, and B. Rezaei, “Highly conductive Faradaic artificial muscle based on nanostructured polypyrrole-bis(trifluoromethylsulfonyl)imide synthesized onto electrospun polyurethane nanofibers,” Sensor Actuat B-Chem., Vol.297, 126736, 2019.
15. [15] C. Plesse, F. Vidal, D. Teyssié, and C. Chevrot, “Conducting polymer artificial muscle fibres: toward an open air linear actuation,” ChemComm., Vol.46, pp. 2910-2912, 2010.
16. [16] B. Weng, X. Liu, R. Shepherd, and G. G. Wallace, “Inkjet printed polypyrrole/collagen scaffold: A combination of spatial control and electrical stimulation of PC12 cells,” Synthetic. Met., Vol.162, pp. 1375-1380, 2012.
17. [17] T. Sizun, T. Patois, M. Bouvet, and B. Lakard, “Microstructured electrodeposited polypyrrole-phthalocyanine hybrid material, from morphology to ammonia sensing,” J. Mater. Chem., Vol.22, pp. 25246-25253, 2012.
18. [18] R. Balint, N. J. Cassidy, and S. H. Cartmell, “Conductive polymers: Towards a smart biomaterial for tissue engineering,” Acta. Biomater., Vol.10, pp. 2341-2353, 2014.
19. [19] S. Cosnier, “Biomolecule immobilization on electrode surfaces by entrapment or attachment to electrochemically polymerized films,” Biosens. Bioelectron., Vol.14, pp. 443-456, 1999.
20. [20] T. Yano, S. K. Chee, K. Yakuwa, S. Harada, and T. Higuchi, “A New Type of Mechanical Transformer with High Stroke Magnification Ratio,” Actuator 2008, 11th Int. Conf. on New Actuators, pp. 71-74, 2008.
21. [21] S. Guo, Y. Sasaki, and T. Fukuda, “A Novel Mobile Microrobot Fin for In-Pipe Inspection,” J. Robot. Mechatron., Vol.15, pp. 616-623, 2003.
22. [22] C. Moraes, J. H. Chen, Y. Sun, and C. A. Simmons, “Microfabricated arrays for high-throughput screening of cellular response to cyclic substrate deformation,” Lab Chip., Vol.10, No.2, pp. 227-234, 2010.
23. [23] P. C. Dartsch and E. Betz, “Response of cultured endothelial cells to mechanical stimulation,” Basic Res. Cardiol., Vol.84, pp. 268-281, 1989.
24. [24] T. Aoto, R. Mashiko, and A. Kaneko, “An Application of Patterned Conductive Polymer to Micro-Actuator,” Proc. the 6th Int. Conf. of Asian Society for Precision Engineering and Nanotechnology, 2015.
25. [25] R. Mashiko, T. Sugihara, T. Aoto, I. Takeda, and A. Kaneko, “Micro-patterning of Conductive Polymer and its Actuation Properties,” Proc. MECATRONICS 2014, OS-5, 2014.
26. [26] K. Kimura, Y. Yanagida, T. Haruyama, E. Kobatake, and M. Aizawa, “Electrically induced neurite outgrowth of PC12 cells on the electrode surface,” J. Biotech., Vol.18, pp. 129-139, 1991.