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

Aim or purpose: This study aims to addresses the critical limitations of conventional hydrogels in cartilage tissue engineering—inadequate porosity and suboptimal mechanical strength. Materials and methods: 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. Results: 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. Conclusions: 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.