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

There 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.

A 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.

The 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.

The 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.