Silicon-dioxide−polyvinylpyrrolidone as a wound dressing for skin defects in a murine model

ObjectiveThere is a high demand for temporary wound dressings that improve wound healing and regeneration. Silicon (as SiO2) has been shown to support the growth and collagen formation in biological systems.MethodsA nanocomposite was made from PVP (polyvinylpyrrolidon), nano-sized silica aggregates and water and served for fabrication of a wet dressing material (SiO2-PVP gel, by cross-linking the gel) and a freeze-dried dressing material (SiO2-PVP fleece). Materials were characterized by SAXS, DSC, EDX and viscosity measurements. A 10 mm circular defect was set on both sides of the back of SKH1-hr mice (n = 40) and both dressing materials were compared with untreated controls. After 3, 6, 9, 12 and 15 days, the defect regions were explanted and evaluated by histomorphometric measurements and CD31-immunohistochemistry.ResultsThe microstructure of the compound was composed of fiber like structures. SiO2 nano-aggregates inside the composite remained stable and embedded in a rigid amorphous PVP fraction. In animal experiments, all groups showed a non-irritated defect closure after 9 days. EDX of SiO2-PVP gel and fleeces revealed SiO2-PVP diffusion into the wound. Wound contraction was significantly enhanced after treatment with SiO2-PVP gel followed by SiO2-PVP fleece compared to controls. Re-epithelialization was increased in SiO2-PVP treated wounds and the regenerated epidermis showed a well-differentiated layer structure compared to untreated controls.ConclusionsThe results indicate that silica diffuses from the dressing into the wound. Both dressings affect the wound healing. The SiO2-based wound dressing may counteract scarring and might be suitable as a temporary wound dressing.