Abstract
A tissue-engineered muscle has a potential to realize a flexible actuator with high efficiency as a bioactuator, whereas mechanical actuators currently used are inflexible and low efficiency. In this study, acellular tissue and collagen gel were used as the scaffold for myoblasts to regenerate the tissue-engineered skeletal muscle and its isometric contractile force was measured. Furthermore, a solid object formed by the micro stereo-lithography system was driven by the tissue-engineered skeletal muscle. A cold suspension of C2C12 cells embedded in Type-I collagen gel was added on and between two collagenous vascular grafts placed 13 mm apart and cultured for 2 days in high-glucose Dulbecco's modified Eagle's medium (HG-DMEM) supplemented with 10% fetal bovine serum and 1% antibiotics. The culture medium was shifted to HG-DMEM supplemented with 7% horse serum and 1% antibiotic to enhance differentiation of the cells to the myotubes. The cells in the collagen gel differentiated to multinuclear myotubes at 12 days after differentiation induction. From the result of force measurement, the isometric contractile force was increased with increase of amplitude, duration, and frequency of the electrical pulse stimulation to the tissue engineered skeletal muscle. Unfused tetanus was generated at 20 Hz when the amplitude and duration were 50 V and 2 ms, respectively. The value of isometric contractile force of twich and unfused tetanus were 145 μN and 180 μN, respectively. The unfused tetanus was not observed at amplitude of 10 V and duration of 2 ms. The solid object having the tissue-engineered skeletal muscle could be driven by electrical pulse and the motion was visible without microscope. These results suggested that it could be possible to realize the development of the bio-actuator with tissue-engineered skeletal muscle.
