Microstructured silicone membrane as an ultra-microskin grafting cover: Transparent and promoting wound healing

Ultra-microskin grafting shows promising prospects for the treatment of deep wounds. However, the survival rate of ultra-microskin and wound healing speed are significantly limited by the covering. This study developed a novel microstructured silicone membrane (MSM) as an optimal covering for ultra-microskin grafts.

A MSM with small concave surface features was fabricated. The membrane's morphology was observed using scanning electron microscopy and laser electron microscopy. Water-vapor transmission rate (WVTR) and hydrophilicity/hydrophobicity were assessed. Cytotoxicity was evaluated using the CCK-8 method, and fibroblasts were seeded on the membrane to observe cell growth. An rat full-thickness skin defect model was used, and ultra-microskin grafts (0.4 mm×0.4 mm) were transplanted onto the wound at a 1:10 enlargement ratio. The wounds were covered with MSM, allograft skin (AS), or vaseline gauze (VG), and the wound healing rate and histological changes were compared.

One side of the MSM is smooth and flat, while the other side is covered with micro convex-concave structures. The membrane is hydrophobic with a WVTR of 638.33 ± 37.50 g/(m²·24 h), similar to normal skin. In vitro toxicity tests showed no significant toxicity, and the cells were able to survive and grow on the membrane. In the rat model, the MSM group showed significantly faster wound healing (59.75 ± 0.87% closure at day 14, 90.10 ± 0.63% at day 21) than both the AS (17.90 ± 0.29% at day 21) and VG groups (28.53 ± 1.11% and 60.88 ± 0.71% at days 14 and 21, respectively; all p < 0.0001). Additionally, it promoted epithelialization, basement membrane formation, and collagen deposition in the dermis, while enhancing cell proliferation, neovascularization, and reducing inflammation at the wound site.

The MSM is transparent, visually clear, and possesses excellent breathability, conformability, and biocompatibility. It provides an optimal moist microenvironment for ultra-microskin grafting and wound healing. The membrane attaches closely to the wound without significant adhesion, preventing graft displacement and clumping, while minimizing damage during dressing changes. This enhances graft survival and accelerates wound healing.