Figure 15.

Skeletal muscle tissue engineering scaffold fabricated using an integrated tissue-organ printer (ITOP). (a) Schematic depiction of construct designed to mimic array of aligned muscle fiber bundles including PCL support pillars (green). (b) 3D printed scaffold before (left) and after (right) removing sacrificial Pluronic F-127 hydrogel. (c) Live/dead staining of cells within hydrogel bundles shows high cell viability immediately after printing. (d) Immunofluorescent staining for myosin heavy chain shows myoblast alignment along the fiber after 7 days of culture. (e) Subcutaneous placement of construct in mouse with dissected common peroneal nerve inserted into construct to promote nerve integration. (f) After 2 weeks of implantation, cells within the construct organized into muscle fiber structures as evidenced by desmin staining and (g) expression of myosin heavy chain and α-BTX. (h) Evidence of nerve integration via doublestaining for α-BTX and neurofilament (NF). (i) Constructs became vascularized as evidenced by expression of von Willebrand factor. Reprinted with permission, Copyright © 2016 Nature Publishing Group.^[12]