The transplantation of full-thickness skin grafts (FTSGs) is important for reconstructing skin barrier and promoting wound healing. Sufficient oxygen supply is closely related to the success of skin grafting. However, full-thickness oxygen delivery is limited by the poor oxygen permeability of skin. Oxygen-releasing sutures (O2 sutures) were developed to facilitate oxygen penetration through full-thickness skin. The O2 sutures delivered 100 times more oxygen than topical gaseous oxygen therapy at a 15 mm depth in the skin model. Under extreme hypoxia (< 0.5% O2, v/v), O2 sutures could also promote endothelial cell proliferation. After the transplantation of FTSGs in mice, O2 sutures accelerated blood re-perfusion and increased the survival area of the skin graft. It is expected that O2 sutures will be adopted in clinical applications to increase the success rate of full-thickness skin transplantation.

Schematic of O2 sutures and mechanism to deliver oxygen in skin. Oxygen-releasing sutures (O2 sutures) are designed to realize full-thickness skin oxygen penetration for skin grafting. Sutures pass through the whole skin layer and step over the obstacle of skin barrier. Thus, O2 sutures deliver much more oxygen ( > 100 folds) to deep skin than topical gaseous therapy and improve the survival of transplanted full-thickness skin grafts.