Regulation and Reconstruction of Cell Phenotype Gradients Along the Tendon-Bone Interface

Tendon-bone interface is prevalent in the human body. It is divided into four zones: tendon (soft tissue), unmineralized fibrocartilage, mineralized fibrocartilage, and bone (hard tissue). Tendon-bone interface is characterized by a cell phenotype gradient that appears in the different zones. The cell phenotype gradients at the tendon-bone interface are orchestrated by specific intracellular molecular mechanisms, extracellular factors, immune signals, and neurovascular factors. These features have inspired scientists to design systems that mimic natural cell phenotype gradients. These biomimetic systems include the construction of cell sheets, regulation of cellular microenvironments, and the design of gradient functional scaffolds. Exploration of methods to mimic cell phenotype gradients is instructional for future clinical applications in reconstituting the tendon-bone interface. The present review elucidates the gradient composition of the tendon-bone interface. The associated regulatory mechanisms and applications are discussed, with the anticipation of creating a mise en scene for future research in interface tissue engineering.