Development of Hybrid Electromagnetic and Mechanical Stimulation System for Enhancement of Nerve Axonal Extension
Recently, the electromagnetic and mechanical stimulation have been recognized as the effective extracellular environmental factor to enhance the defected peripheral nerve tissue regeneration. We designed and fabricated a bioreactor device, which can load the uniform AC magnetic field (ACMF) and the uniform tensile strain to stimulate PC12 nerve cell. For ACMF stimulation system, we used the pole piece structure to enable the uniform ACMF and in-situ microscopic observation. We confirmed the uniformity of magnetic field in the experiments. Further, the uniform strain in the stretch stimulation device was confirmed, even a slightly deviation from the designed strain was observed. It was a negligible small error. Next, we validated the effectiveness of PC12 axonal extension enhancement by two stimulation methodologies, ACMF and the cyclic stretch, under individual and combined stimulation conditions. ACMF showed a best enhancement effect on axonal extension, such as 70 μm at 96 h culture period, which rate is larger than the case of control. On the other hand, the stretch stimulation caused the exfoliation of cells. Hybrid stimulation succeeded to inhibit the exfoliation. However, the extensional rate was less than the case of ACMF. These results can be used to fabricate a bioreactor of nerve cell regeneration.