Structurally and Functionally Optimized Silk‐Fibroin–Gelatin Scaffold Using 3D Printing to Repair Cartilage Injury In Vitro and In Vivo

TLDR

Articular cartilage repair remains a major clinical challenge, and recent tissue‑engineering approaches combine bone marrow stem cells with biomaterials to enable one‑step in situ repair. The study aims to design a structurally and functionally optimized scaffold for cartilage tissue engineering. The scaffold is fabricated by integrating silk fibroin with gelatin and a BMSC‑specific affinity peptide using 3‑D printing technology. The silk‑fibroin/gelatin scaffold balances mechanical properties and degradation, retains BMSCs, blocks blood clots, provides mechanical protection, and creates a suitable 3‑D microenvironment, resulting in superior cartilage repair in a knee joint and suggesting applicability to other joint cartilages, warranting further large‑animal studies.

Abstract

Articular cartilage repair remains a great challenge for clinicians and researchers. Recently, there emerges a promising way to achieve one-step cartilage repair in situ by combining endogenic bone marrow stem cells (BMSCs) with suitable biomaterials using a tissue engineering technique. To meet the increasing demand for cartilage tissue engineering, a structurally and functionally optimized scaffold is designed, by integrating silk fibroin with gelatin in combination with BMSC-specific-affinity peptide using 3D printing (3DP) technology. The combination ratio of silk fibroin and gelatin greatly balances the mechanical properties and degradation rate to match the newly formed cartilage. This dually optimized scaffold has shown superior performance for cartilage repair in a knee joint because it not only retains adequate BMSCs, due to efficient recruiting ability, and acts as a physical barrier for blood clots, but also provides a mechanical protection before neocartilage formation and a suitable 3D microenvironment for BMSC proliferation, differentiation, and extracellular matrix production. It appears to be a promising biomaterial for knee cartilage repair and is worthy of further investigation in large animal studies and preclinical applications. Beyond knee cartilage, this dually optimized scaffold may also serve as an ideal biomaterial for the regeneration of other joint cartilages.