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Rapid and functional bone-tendon (B-T) healing remains a difficulty in clinical practice. Tissue engineering has emerged as a promising strategy to address this problem. However, the majority of tissue engineering scaffolds are loaded with stem cells to enhance the regenerability in B-T healing, which is complicated and inconvenient for clinical application. Accordingly, developing a cell-free scaffold with chemotactic function and chondrogenic inducibility may be an effective approach. In this study, a collagen affinity peptide derived from the A3 domain of von Willebrand factor (a hemostasis factor) was fused into the C-terminal of a stromal cell-derived factor-1α (SDF-1α) to synthesize a recombinant SDF-1α capable of binding collagen and chemotactic activity. The recombinant SDF-1α was then tethered on the collagen fibers of a book-shaped acellular fibrocartilage scaffold (BAFS), thus fabricating a novel scaffold (C-SDF-1α/BAFS) with chemotactic function and chondrogenic inducibility. In vitro tests determined that this scaffold was noncytotoxic and biomimetic, could attract stem cells migrating to the scaffold using sustainably released C-SDF-1α, and inducedthe interacting stem cells down the chondrogenic lineage. In vivo, the C-SDF-1α/BAFS significantly enhanced the B-T healing in a rabbit partial patellectomy model, as shown by the larger cartilaginous metaplasia region, better fibrocartilage regeneration, additional bone formation, and improved biomechanical properties. Therefore, the findings of the study demonstrate that the C-SDF-1α/BAFS could potentially be applied for B-T healing., (© 2020 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Determining the influence of tissue composition on the osmotic swelling stress of articular cartilage and meniscus fibrocartilage is important to enhance our understanding of physiology and disease. This osmotic swelling stress is critical for the load-bearing capability of both tissues and results in part due to the interactions between the negatively charged sulfated glycosaminoglycan (sGAG) chains and the ionic interstitial fluid. Changes in sGAG content, as those occurring during the progression of degenerative joint disease, alter such interactions. Here, we compare the time-varying effects of altered osmotic environments on the confined compression swelling behavior of bovine tissues spanning a range of sGAG concentrations: juvenile articular cartilage, juvenile and adult meniscus, and juvenile cartilage enzymatically degraded to reduce its sGAG content. The transient response to changes in bath conditions was evaluated for explants assigned to one of three compressive offsets (5%, 10%, or 15% strain) and one of three bath conditions (0.1X, 1X, or 10X phosphate-buffered saline). Our results show that relative responses to alterations to the osmotic environment are consistent across native tissues but differ for degraded juvenile cartilage, demonstrating that changes in sGAG do not completely recapitulate the native swelling behaviors. Further, we found a strong correlation between aggregate modulus and sGAG/collagen, as well as between sGAG and collagen contents across native tissue types, suggesting some conservation of composition-function relationships across a range of tissue types with varying sGAG concentrations. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:785-792, 2020., (© 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)