Human collagen-based multilayer scaffolds for tendon-to-bone interface tissue engineering

The natural tendon-to-bone region has a gradient in structure and composition, which is translated into a spatial variation of chemical, physical, and biological properties. This unique transitional tissue between bone and tendon is not normally recreated during natural bone-to-tendon healing. In this study, we have developed a human collagen-based multilayer scaffold mimicking the tendon-to-bone region. The scaffold consists of four different layers with the following composition gradient: (a) a tendon layer composed of collagen; (b) an uncalcified fibrocartilage layer composed of collagen and chondroitin sulfate; (c) a calcified fibrocartilage layer composed of collagen and less apatite; (d) a bone layer composed of collagen and apatite. The chemical, physical, and mechanical properties of the scaffold were characterized by a scanning electron microscope, porosimeter, universal tensile machine, Fourier transform infrared spectrometer, energy dispersive X-ray analysis apparatus, and thermogravimetric analysis apparatus. The multilayer scaffold provided a gradual transition of the physical, chemical, and mechanical environment and supported the adhesion and proliferation of human fibroblasts, chondrocytes, and osteoblasts toward each corresponding matrix. Overall, our results suggest the feasibility of a human collagen-based multilayer scaffold for regeneration of hard-to-soft interface tissues.