Oral nanotherapeutics based on Antheraea pernyi silk fibroin for synergistic treatment of ulcerative colitis

Ulcerative colitis (UC) with its rapidly increasing incidence has become an emerging challenge for public health. Therapeutic agents are required to be specifically delivered to colon epithelial cells and macrophages with controlled release in the cytoplasm for wound healing, inflammation alleviation, and microbiota rebalance. As a promising biomaterial for accomplishing this, Antheraea pernyi silk fibroin (ApSF) was selected and engineered to form nanoparticles (NPs) loaded with the anti-inflammatory drug, resveratrol (Res). The intrinsic features of these fabricated Res-ApNPs included targeting of colonic epithelial cells and macrophages, lysosomal escape capacity, and responsiveness to pH, reactive oxygen species (ROS), and glutathione, which were pertinent to their functional units such as arginine-glycine-aspartate tripeptides, α-helixes, β-sheets, and disulfide bonds, enabling on-demand release of Res molecules in the cytoplasm of target cells. The Res-ApNP treatment restored damaged colonic epithelial barriers, polarized macrophages to type M2, alleviated inflammatory reactions, and reduced the level of intracellular ROS. Oral treatment with chitosan-alginate hydrogels embedded with Res-ApNPs substantially relieved UC symptoms, as evidenced by decreased colonic inflammation, increased synthesis of tight-junction proteins, and rebalanced intestinal microbiota. Our findings suggest that these high-performance ApSF-based NPs can be developed as effective drug carriers for oral UC treatment.