Enhanced skeletal muscle formation on microfluidic spun gelatin methacryloyl (GelMA) fibres using surface patterning and agrin treatment.

Bioengineered functional muscle tissues are beneficial for regenerative medicine due to their treatment potential for various debilitating disorders, including myopathy and traumatic injuries. However, the contractile properties of engineered muscle constructs are lacking compared with their native counterparts. Here, we used microfluidic spinning to fabricate photocrosslinkable gelatin methacryloyl (GelMA) hydrogel fibres with well-defined surface morphologies for engineering muscle tissues. We examined whether the combination of topographical cues from surface micropatterning and biochemical stimulation with recombinant agrin can improve the generation of bioengineered muscle tissue. Topographical cues on micropatterned fibres promoted alignment of C2C12 myoblasts and augmented myotube formation during differentiation, as assessed by increased myotube length, aspect ratio, and the elevated mRNA expression of myogenic genes. Moreover, agrin treatment significantly increased acetylcholine receptor expression/clustering and myotube formation and upregulated dystrophin expression in differentiated C2C12 myotubes. Interestingly, the combination of topographical cues with agrin treatment further enhanced myotube maturation and functionality as shown by improved contractility under electrical stimulation. Thus, combining topographical cues and agrin treatment improved functions of engineered muscle tissue, which has potential in biorobotics, drug screening, tissue engineering, and regenerative medicine.