Research & Innovation
Publications
Embroidered Silk Fibroin Scaffolds for ACL Tissue Engineering
PMU Authors
Yasir Majeed, Clemens Gogele, Christian Werner, Tobias Braun, Gundula Schulze-Tanzil
All Authors
Yasir Majeed, Clemens Gogele, Cindy Elschner, Christian Werner, Tobias Braun, Judith Hahn, Ricardo Bernhardt, Udo Krause, Bernd Minnich, Gundula Schulze-Tanzil
Journal association
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Abstract
Anterior cruciate ligament (ACL) rupture causes joint instability and increases the risk of osteoarthritis due to the ligament's limited healing capacity. Silk, particularly from Bombyx mori, combines high cytocompatibility with robust biomechanical properties. Its main components are fibroin and sericin, with the latter usually being removed to reduce immunogenicity and improve biocompatibility. Silk threads were processed either as raw silk (designated as "untreated") or subjected to a patented degumming procedure (DE102021118652A1) to obtain purified silk. Both variants were used alone or in combination with poly(L-lactic acid-co-caprolactone) (P(LA-CL)) fibers, yielding four scaffold groups: untreated silk, purified silk, untreated silk/P(LA-CL), and purified silk/P(LA-CL). Three-layer scaffolds were fabricated using a zigzag embroidery pattern. Structural analysis revealed scaffold porosity of approximate to 38% for silk, approximate to 46% for purified silk, and up to approximate to 70% for scaffolds containing P(LA-CL). Uniaxial tensile testing showed that purified silk scaffolds achieved the highest maximum force at break (approximate to 684 N), whereas elongation at maximum force was limited in the hybrid scaffolds-silk/P(LA-CL) approximate to 28% and p-silk/P(LA-CL) approximate to 32%-despite the high intrinsic extensibility of P(LA-CL). All scaffolds supported cell adhesion and showed no cytotoxicity. P-silk and p-silk/P(LA-CL) scaffolds exhibited the highest fibroblast adherence and pronounced paxillin expression, indicating strong cell-material interactions. Gene expression of ligament-related ECM components and connexin 43 was maintained across all groups. These results demonstrate that embroidered silk fibroin scaffolds provide a reproducible architecture with tunable porosity and mechanical properties, supporting fibroblast colonization and ligament-specific ECM expression. Such scaffolds represent promising candidates for ACL tissue engineering and future graft development.
Keywords
ANTERIOR CRUCIATE LIGAMENT, Silk, P(la-cl), Embroidery, Ligament fibroblasts