Development of a multifunctional bioreactor to evaluate the promotion effects of cyclic stretching and electrical stimulation on muscle differentiation

Wei-Wen Hu; Yen-Chi Chen; Chia-Wen Tsao; Shen-Liang Chen; Chung-Yuh Tzeng

doi:10.1002/btm2.10633

Development of a multifunctional bioreactor to evaluate the promotion effects of cyclic stretching and electrical stimulation on muscle differentiation

Bioeng Transl Med. 2023 Dec 7;9(2):e10633. doi: 10.1002/btm2.10633. eCollection 2024 Mar.

Authors

Wei-Wen Hu¹, Yen-Chi Chen¹, Chia-Wen Tsao², Shen-Liang Chen³, Chung-Yuh Tzeng^{4

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Affiliations

¹ Department of Chemical and Materials Engineering National Central University Taoyuan Taiwan.
² Department of Mechanical Engineering National Central University Taoyuan Taiwan.
³ Department of Life Sciences National Central University Taoyuan Taiwan.
⁴ Department of Orthopedics Taichung Veterans General Hospital Taichung Taiwan.
⁵ Department of Rehabilitation Jen-Teh Junior College of Medicine, Nursing and Management Miaoli Taiwan.
⁶ Department of Medicinal Botanicals and Foods on Health Applications Da-Yeh University Changhua Taiwan.
⁷ Institute of Biomedical Sciences National Chung Hsing University Taichung Taiwan.

Abstract

A multifunctional bioreactor was fabricated in this study to investigate the facilitation efficiency of electrical and mechanical stimulations on myogenic differentiation. This bioreactor consisted of a highly stretchable conductive membrane prepared by depositing polypyrrole (PPy) on a flexible polydimethylsiloxane (PDMS) film. The tensile deformation of the PPy/PDMS membrane can be tuned by adjusting the channel depth. In addition, PPy/PDMS maintained its electrical conductivity under continuous cyclic stretching in the strain range of 6.5%-13% for 24 h. This device can be used to individually or simultaneously perform cyclic stretching and electrical stimulation. The results of single stimulation showed that either cyclic stretching or electrical stimulation upregulated myogenic gene expression and promoted myotube formation, where electrical stimulation improved better than cyclic stretching. However, only cyclic stretching can align C2C12 cells perpendicular to the stretching direction, and electrical stimulation did not affect cell morphology. Myosin heavy chain (MHC) immunostaining demonstrated that oriented cells under cyclic stretching resulted in parallel myotubes. The combination of these two stimuli exhibited synergetic effects on both myogenic gene regulation and myotube formation, and the incorporated electrical field did not affect the orientation effect of the cyclic stretching. These results suggested that these two treatments likely influenced cells through different pathways. Overall, the simultaneous application of cyclic stretching and electrical stimulation preserved both stimuli's advantages, so myo-differentiation can be highly improved to obtain abundant parallel myotubes, suggesting that our developed multifunctional bioreactor should benefit muscle tissue engineering applications.

Keywords: bioreactor; cyclic stretching; electrical stimulation; myoblasts; myogenic differentiation; polydimethylsiloxane; polypyrrole.