A Bi-Layer PVA/CMC/PEG Hydrogel with Gradually Changing Pore Sizes for Wound Dressing.

Wound dressings are vital for cutaneous wound healing. In this study, a bi-layer dressing composed of polyvinyl alcohol/carboxymethyl cellulose/polyethylene glycol (PVA/CMC/PEG) hydrogels is produced through a thawing-freezing method based on the study of the pore size of single-layer hydrogels. Then the physical properties and healing of full-thickness skin defects treated with hydrogels are inspected. The results show that the pore size of the single-layer PVA/CMC/PEG hyrogel can be controlled. The obtained non-adhesive bi-layer hydrogels show gradually increasing pore sizes from the upper to the lower layer and two layers are well bonded. In addition, bi-layer dressings with good mechanical properties can effectively prevent bacterial penetration and control the moisture loss of wounds to maintain a humid environment for wounds. A full-thickness skin defect test shows that bi-layer hydrogels can significantly accelerate wound closure. The experiment indicates that the bi-layer PVA/CMC/PEG hydrogels can be used as potential wound dressings.