Dual-Engineered 3D-Printed Silma Hydrogels: Nanofibers And Peo Porosity

This study aims to addresses the critical limitations of conventional hydrogels in cartilage tissue engineering—inadequate porosity and suboptimal mechanical strength. The materials used in this study include methacrylated silk fibroin (SilMA), poly(ethylene oxide) (PEO) as a sacrificial template, and homogenized electrospun silk fibroin nanofibers (NFs).A water-in-water emulsification strategy was employed to create the porous architecture using PEO as a sacrificial template. Homogenized NFs were incorporated into the bioink at different weight percentages (1-2 wt%). The hydrogel's structural modulation, compressive strength, elastic modulus, 3D printability, biocompatibility, and cartilage-related gene expression were evaluated.In vivo experiments were conducted to confirm the efficacy of the developed hydrogel in promoting cartilage regeneration. The pore-forming process resulted in remarkable structural modulation, achieving over 100% increase in average pore diameter and 75% enhancement in overall porosity compared to non-porous counterparts. However, this structural modification compromised the compressive modulus by approximately 25%. The introduction of NFs (1-2 wt%) not only recovered the compressive strength and elastic modulus (near to SilMA hydrogels) but also improved the 3D printability of SilMA/PEO hydrogels. Furthermore, the hydrogels demonstrated excellent biocompatibility and markedly upregulated cartilage-related gene expression, including Collagen II, Aggrecan and Sox9. This study successfully developed a dual-strategy approach for cartilage tissue engineering by integrating NFs reinforcement and PEO-induced porosity. The innovative cell-laden porous SilMA hydrogel system demonstrated significant improvements in structural properties, mechanical strength, biocompatibility.