Bioassembly of Myoblast Spheroids in Electrofibrillated Scaffolds for 3D Muscle Tissue Biofabrication.

One of the key challenges in tissue engineering is recreating the extracellular matrix (ECM), which is essential for cell function, especially in anisotropic tissues like muscle, where tissue morphology dictates contraction and motion. The recently developed method of melt electrofibrillation offers a promising platform for producing highly aligned nanofibrillar scaffolds that mimic collagen. These scaffolds are created by melt electrowriting a blend of polycaprolactone (PCL) and polyvinyl acetate (PVAc), which are precisely printed in a box geometry. After washing out the PVAc, aligned nano-scaled PCL fibrils remain. These fibers provide extracellular matrix-like cues for cells to mature, encouraging them to align and interact with the structure. This study showcases the application of C2C12 muscle cells, which are assembled into spheroids and seeded on the scaffolds. Over 21 days, the cells align along the fibrils, colonize the scaffold, and, when exposed to differentiation media, begin forming early-stage myotubes and express myogenic factors, such as Myogenin. This demonstrates that the synthetic matrix is a useful tool for studying the interaction of aligned 3D matrices in muscle tissue differentiation.