Tissue-engineered liver using 3D-printed silk fibroin scaffolds loaded with stem cells for the treatment of acute liver injury

Liver tissue engineering offers a promising therapeutic strategy for acute liver injury (ALI). Although traditional biomaterial scaffolds exhibit favorable biocompatibility, they still face limitations in the construction of precise structures and the design of functional properties, making it difficult to fully meet the requirements for the repair of specific organs and tissues. In recent years, 3D-printed silk fibroin (3D-SF) scaffolds have demonstrated broad application prospects in tissue and organ repair owing to their excellent biological properties. In this study, a silk fibroin (SF) solution was used as bioink to successfully fabricate 3D-SF scaffolds with fine microarchitectures and mechanical properties matching those of ALI-affected liver tissue, employing a 4K-resolution micro-nano 3D printer integrated with digital light processing technology. <i>In vitro</i> results demonstrated that adipose-derived mesenchymal stem cells (ADSCs) were able to adhere, proliferate and differentiate into hepatocyte-like cells within the 3D-SF scaffolds under specific inductive factors. <i>In vivo</i>, after transplanting 3D-SF onto the liver surface of ALI mice, liver function was partially improved and hepatic injury was repaired. The combination of ADSCs and 3D-SF (ADSCs@3D-SF) significantly enhanced the efficiency of ALI repair. Pathological analysis revealed the formation of vascular and biliary duct-like structures at the scaffold-liver interface. Transcriptomic analysis further indicated that ADSCs@3D-SF upregulated the mRNA and protein expression levels of β-Catenin, LEF1 and Cyclin D1 in the Wnt signaling pathway, promoting cell proliferation and facilitating the recovery from ALI. These findings suggest that ADSCs@3D-SF hold promise as a scaffold candidate for liver tissue engineering, offering a novel strategy for the treatment of liver diseases and the reconstruction of vascular systems.