电刺激提高骨骼肌微纤维致动器致动性能

Electrical Stimulation Enhances Actuation Performance of Skeletal Muscle Microfiber Actuators

生物混合致动器是生物混合机器人的重要部分,该研究利用可光交联水凝胶(GelMA)作为小鼠成肌细胞C2C12细胞的细胞间基质,制作了一种直径为500μm的微纤维致动器,并探究长时间电刺激对微纤维中C2C12细胞分化及致动能力的影响。该研究利用不同电压的方波脉冲信号在细胞分化期间对细胞进行每天15 min的电刺激,同时利用刚性支架固定微纤维以保持其方向与电场方向一致,并对微纤维施加30%机械拉伸。为表征电刺激对细胞分化的影响,利用ImageJ软件统计肌管长度、宽度与取向角,利用肌球蛋白重链(MHC)荧光染色表征其肌球蛋白重链表达,利用ANSYS有限元仿真计算致动器主动张力。结果表明,该微纤维致动器适合C2C12细胞生长并使其分化形成可收缩的骨骼肌,通过分化期间的长时间电刺激可有效促进C2C12细胞的分化、增大骨骼肌中肌管尺寸并提高微纤维致动器致动性能。其中18 V的电刺激效果最为显著,能使肌管长度有效提高30%,肌管宽度提高24%,肌管主动张力提高198%,使其达到0.21μN。含有性能增强的骨骼肌的微纤维致动器可进一步应用于生物混合机器人组装领域,在药物筛选和骨骼肌再生等基础研究领域也有较强的应用潜力。

The biohybrid actuator is an important part of the biohybrid robot.In this study,a microfiber actuator with a diameter of 500μm was fabricated by using photocrosslinkable hydrogel(GelMA)as the intercellular matrix of mouse myoblast C2C12 cells and explore the effect of long-term electrical stimulation on the differentiation and actuation ability of C2C12 cells in microfibers.In this study,square wave pulse signals of different voltages were used to electrically stimulate cells for 15 min per day during cell differentiation,at the same time,a rigid scaffold is used to apply 30%mechanical stretching to the microfibers,as well as to immobilize the microfibers to maintain the direction consistent with the direction of the electric field.In order to characterize the effect of electrical stimulation on cell differentiation,ImageJ software was used to count the length,width and orientation angle of MHC(myotubes,myosin heavy chain).Fluorescence staining was used to characterize the expression of myosin heavy chain,and ANSYS finite element simulation was used to calculate the active tension of the actuator.The results show that the microfiber actuator is suitable for C2C12 cells to grow and differentiate into contractile skeletal muscle,and long-term electrical stimulation during differentiation can effectively promote the differentiation of C2C12 cells,increase the size of myotubes in skeletal muscle,and increase actuation performance of the microfibers actuator.The electrical stimulation effect of the 18 V experimental group was the most significant,which can effectively increase the length of myotubes by 30%,increase the width of myotubes by 24%,and increase the active tension of myotubes by 198%,reaching 0.21μN.Microfiber actuators containing enhanced skeletal muscle can provide further applications in the field of biohybrid robotic assembly,and also have strong application potential in basic research fields such as drug screening and skeletal muscle regeneration.