Figure 3.

Spatiotemporal deliveryof GFs via 3D-printed PCL scaffolds improved healing of the tendon-to-bone fibrocartilaginous interface in vivo. Three-layered scaffolds with spatially embedded GF-μS(+GF) or empty μS (−GF) were implanted between tendon and bone at the supraspinatus tendon-to-bone insertion site and tissue samples were harvested 4 weeks post-operatively (a). Grossly, the harvested tissues showed no noticeable difference between +GF and −GF (a). Picrosirius red staining showed improved healing of the tendon-to-bone interface with a native-like densely aligned collagen structure with +GF scaffolds, compared with the disrupted collagen structure with −GF scaffolds (b). Safranin O-stained tissue sections showed reconstruction of fibrocartilaginous interface with +GF scaffolds, reminiscent of the native state, compared with the lack of a fibrocartilaginous matrix with −GF scaffolds (c), consistentwith COL-II immunofluorescence (d). Asterisks indicate the remained scaffold structure.