Aim: To mimic the ultrastructural morphology of the meniscus with nanofiber scaffolds coupled with controlled growth factor delivery to modulate cellular performance for tissue engineering of menisci. Methods: The authors functionalized collagen nanofibers by conjugating heparin to the following growth factors for sustained release: PDGF-BB, TGF-β1 and CTGF. Results: Incorporating growth factors increased human meniscal and synovial cell viability, proliferation and infiltration in vitro, ex vivo and in vivo; upregulated key genes involved in meniscal extracellular matrix synthesis and enhanced generation of meniscus-like tissue. Conclusion: The authors' results indicate that functionalizing collagen nanofibers can create a cell-favorable micro- and nanoenvironment and can serve as a system for sustained release of bioactive factors.
Keywords: CTGF; PDGF-BB; TGF-β1; heparin conjugation; meniscus; nanofibers; protein scaffolds; tissue engineering.
Lay abstract Meniscal tears are a common injury to the part of the knee called the meniscus. Loss of meniscal tissue can lead to arthritis. In this study, the authors aimed to recreate the structure of the human meniscus using very thin (nanometers in diameter) fibers made of collagen. The authors also attached proteins called growth factors to the fibers. The addition of these proteins increased the growth rate of cells collected from human knee tissue. The levels of important genes involved in meniscal tissue formation were increased in these cells. These results show that adding proteins such as growth factors to collagen nanofibers can create an environment beneficial to growing meniscal tissue. Successful development of this technology could help in repairing meniscal damage in people.