Collagen/polyvinyl alcohol scaffolds combined with platelet-rich plasma to enhance anterior cruciate ligament repair

In anterior cruciate ligament (ACL) repair methods, the continuous enzymatic erosion of synovial fluid can impede healing and potentially lead to repair failure, as well as exacerbate articular cartilage wear, resulting in joint degeneration. Inspired by the blood clot during medial collateral ligament healing, we developed a composite scaffold comprising collagen (1 %, w/v) and polyvinyl alcohol (5 %, w/v) combined with platelet-rich plasma (PRP). The composite scaffold provides a protective barrier against synovial erosion for the ruptured ACL, while simultaneously facilitating tissue repair, thereby enhancing the efficacy of ACL repair techniques. The composite scaffold is primarily formed through hydrogen bonding between molecular chains and physical cross-linking of microcrystalline regions using a simple cyclic freeze-thaw method, resulting in improved mechanical properties and an extended degradation period. The maximum tensile fracture load of the composite scaffold reached 5.99 ± 0.30 N. The incorporation of PRP facilitates cell migration, proliferation, and blood vessel growth by enabling slow release of various growth factors. In vivo results demonstrate that this composite scaffold promotes rabbit hindlimb rupture ACL healing by stimulating fibroblast proliferation, collagen deposition, microvascular formation, and proprioceptor generation. Furthermore, it effectively reduces meniscus and cartilage wear while mitigating bone arthritis and joint degenerative diseases. Overall, our proposed composite scaffold holds great promise as a candidate for ACL healing.