Construction of a three-layered “sandwich” tubular scaffold based on electro-spinning and electro-direct writing for esophageal muscle layers repair

• Integrated electro-spinning membrane with suspended electro-direct-written fibers enables biomimetic inner-circular/outer-longitudinal muscle layer reconstruction. • 160 µm diameter electro-direct-written fibers maximally guided myoblast alignment and supported myotube formation. • The monolithic and seamless of the e-spinning cylindrical scaffold contributed to its favorable permeability and mechanical properties. The reconstruction of esophageal muscle layers presents significant challenges, particularly in replicating the inner circular and outer longitudinal structures essential for swallowing function. A key challenge lies in the bioengineering replication of these orthogonal structures. In this work, electro-spinning (e-spinning) and electro-direct writing (e-writing) have been integrated to prepare a three-layered “sandwich” tubular scaffold, consisting of an inner ring of aligned e- writing fibers, a middle e-spinning membrane, and an outer layer of longitudinally oriented e- writing fibers. The cell experiment demonstrated that such a three-layer scaffold could guide myoblast cells to form an inner and outer longitudinal arrangement and fuse to form myotubes. Considering the e- writing fiber’s cellular orientation and load-bearing capability, a filament diameter of 160 µm was identified as optimal for muscle layer repair. The monolithic and seamless of the e-spinning cylindrical scaffold contributed to its favorable permeability and mechanical properties. Preliminary animal experiments demonstrated that the scaffold promoted oriented muscle regeneration at the implantation site, compared to the control region. In conclusion, this research provides a new method for preparing tubular scaffolds to repair the esophageal muscle layer, laying the foundation for clinical applications of muscle layer repair, which has important scientific and engineering significance.