Rapid Construction of Tissue-engineered Skin for Repairing Difficult-to-heal Wounds

Autologous split-thickness skin (0.15-0.2 mm) is harvested from the donor site at a donor-to-wound area ratio of 1:20-30. The harvested skin is processed using a specialized cell sorter to isolate autologous epidermal stem cells (EpiSCs) with >93% viability within 30 minutes. The cell suspension is adjusted to a concentration of ≥1×10⁶ cells/mL and loaded onto a tissue-engineered scaffold via spraying or immersion (3-5 minutes). The cell-seeded scaffold is then applied to the wound bed. Depending on wound condition: (1) One-step procedure: scaffold and a split-thickness skin graft (0.15-0.2 mm) are applied simultaneously; (2) Two-step procedure: scaffold is implanted first, followed by split-thickness skin graft at 14±3 days post-primary surgery. Negative pressure wound therapy (-100 to -125 mmHg) is applied as needed.

The same tissue-engineered scaffold (without cell loading) is used. Autologous split-thickness skin graft (0.15-0.2 mm thickness) is harvested. The acellular scaffold is applied to the debrided wound bed followed by coverage with the split-thickness skin graft. The surgical procedure, postoperative wound care, negative pressure wound therapy (-100 to -125 mmHg when indicated), and follow-up protocol are identical to those in the experimental arm. This comparator represents the current standard of care for composite skin grafting in the participating centers.