Hierarchical Porous Egg White Hydrogel Promotes Diabetic Wound Closure through Topography-Guided Cell Recruitment.

Skin healing often results in scarring or pathological conditions like keloids due to abnormal cell proliferation. These outcomes are attributed to abnormal proliferation or functional defects in skin cells. Hydrogels, mimicking the extracellular matrix, can guide hierarchical cell alignment for improved regeneration. Inspired by egg white's foaming ability, we engineered a bilayer hydrogel dressing: a porous dermis layer via whipped egg white and a dense epidermis layer crosslinked with calcium. The artificial egg white skin (EWS) was tested in in vitro cell culture and in vivo application on mouse wounds. RNA sequencing explored the specific mechanism of EWS on cells. EWS features a multistage macroporous structure mimicking skin's longitudinal mechanical performance. This migration inducive property of egg white facilitates directional migration and allows for the vertical stacking of keratinocytes and fibroblasts. The collaboration of cells enhances expression of positive chemokines and growth factors, shortening inflammation reaction and improving wound healing. Transcriptome sequencing reveals a substantial up-regulation of genes related to cell cycle and metabolism. EWS offers a cost-effective and efficient platform for biomimetic skin dressing and shows potential for other applications in regenerative medicine.