ABSTRACT
Background: Tendon-bone interface (TBI) repair is slow and challenging owing to its hierarchical structure, gradient composition, and complex function. In this work, enlightened by the natural characteristics of TBI microstructure and the demands of TBI regeneration, a structure, composition, and function-based scaffold was fabricated. Methods: The biomimetic scaffold was designed based on the "tissue-inducing biomaterials" theory: (1) a porous scaffold was created with poly-lactic-co-glycolic-acid, nano-hydroxyapatite and loaded with BMP2-gelatinmp to simulate the bone (BP); (2) a hydrogel was produced from sodium alginate, type I collagen, and loaded with TGF-ß3 to simulate the cartilage (CP); (3) the L-poly-lactic-acid fibers were oriented to simulate the tendon (TP). The morphology of tri-layered constructs, gelation kinetics, degradation rate, release kinetics and mechanical strength of the scaffold were characterized. Then, bone marrow mesenchymal stem cells (MSCs) and tenocytes (TT-D6) were cultured on the scaffold to evaluate its gradient differentiation inductivity. A rat Achilles tendon defect model was established, and BMSCs seeded on scaffolds were implanted into the lesionsite. The tendon-bone lesionsite of calcaneus at 4w and 8w post-operation were obtained for gross observation, radiological evaluation, biomechanical and histological assessment. Results: The hierarchical microstructures not only endowed the scaffold with gradual composition and mechanical properties for matching the regional biophysical characteristics of TBI but also exhibited gradient differentiation inductivity through providing regional microenvironment for cells. Moreover, the scaffold seeded with cells could effectively accelerate healing in rat Achilles tendon defects, attributable to its enhanced differentiation performance. Conclusion: The hierarchical scaffolds simulating the structural, compositional, and cellular heterogeneity of natural TBI tissue performed therapeutic effects on promoting regeneration of TBI and enhancing the healing quality of Achilles tendon. The translational potential of this article: The novel scaffold showed the great efficacy on tendon to bone healing by offering a structural and compositional microenvironment. The results meant that the hierarchical scaffold with BMSCs may have a great potential for clinical application.
ABSTRACT
Hyaluronic-acid- and silk-fibroin-based nanofibrous mats loaded with proanthocyanidins and collagen peptides were fabricated as multifunctional facial masks using electrospinning. Their morphology, hygroscopicity and moisture retention, DPPH, ABTS free radical scavenging abilities, and cytocompatibility were investigated. The results showed that the nanofibrous mats were dense and uniform, with an average diameter ranging from 300 to 370 nm. The nanofibrous mats exhibited satisfactory moisture retention, oxidation resistance, biocompatibility, especially excellent DPPH, and ABTS free radical scavenging capacities. DPPH free radical scavenging activity was 90% with 15 mg/L nanofibers, and ABTS free radical scavenging activity was 90% with 0.005 mg/L nanofibers. The nanofibrous mats protected fibroblasts from oxidative stress damage induced by tert-butyl hydroperoxide (t-BHP) and significantly promoted their proliferation. Compared with traditional liquid masks and semi-solid facial masks, the multifunctional nanofibrous mats prepared in this study contained fewer additives, which has significant advantages in terms of safety. The nanofibrous mats were rapidly dissolved within 5 s after being sprayed with water, which facilitated the release and penetration of active ingredients for skincare. Therefore, the multifunctional nanofibrous mats displayed excellent moisture retention, oxidation resistance, and biocompatibility, indicating promising translational potential as facial masks and providing a valuable reference for skincare.