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

Objective: 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. Methods: 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 CD31immunohistochemistry. Results: 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. Reepithelialization was increased in SiO2-PVP treated wounds and the regenerated epidermis showed a well-differentiated layer structure compared to untreated controls. Conclusions: 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. (C) 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.