Engineering Anisotropic Muscle Tissue using Acoustic Cell Patterning

Tissue engineering has offered unique opportunities for disease modelling and regenerative medicine, however, the success of these strategies is dependent upon faithful reproduction of native cellular organization. Here, we report that ultrasound standing waves can be used to organize myoblast populations in material systems for the engineering of aligned muscle tissue constructs. Patterned muscle engineered using type I collagen hydrogels exhibited significant anisotropy in tensile strength, and under mechanical constraint, produced microscale alignment on a cell and fiber level. Moreover, acoustic pattering of myoblasts in gelatin methacryloyl hydrogels significantly enhanced myofibrillogenesis and promoted the formation of muscle fibers containing aligned bundles of myotubes, with a width of 120-150 μm and a spacing of 180-220 μm. The ability to remotely pattern fibers of aligned myotubes without any material cues or complex fabrication procedures represents a significant advance in the field of muscle tissue engineering. In general, these results are the first instance of engineered cell fibers formed from the differentiation of acoustically-patterned cells. We anticipate that this versatile methodology can be applied to many complex tissue morphologies, with broader relevance for spatially-organized cell cultures, organoid development and bioelectronics.