Treatment of a burn animal model with functionalized tridimensional electrospun biomaterials.

Laminin-functionalized poly-d,l-lactic acid scaffolds were produced. Following this, mesenchymal stem cells and keratinocytes were seeded on biomaterials for the in vivo experiments, where the biomaterials with or without cells were implanted. The analysis is comprised of the visual aspect and mean size of the lesion plus the histology and gene expression. The results showed that the cells occupied all the structure of the scaffolds in all the groups. After nine days of in vivo experiments, the defect size did not show statistical difference among the groups, although the groups with the poly-d,l-lactic acid/Lam biomaterial had the lowest lesion size and presented the best visual aspect of the wound. Gene expression analysis showed considerable increase of tumor growth factor beta 1 expression, increased vascular endothelial growth factor and balance of the BAX/Bcl-2 ratio when compared to the lesion group. Histological analysis showed well-formed tissue in the groups where the biomaterials and biomaterials plus cells were used. In some animals, in which biomaterials and cells were used, the epidermis was formed throughout the length of the wound. In conclusion, these biomaterials were found to be capable of providing support for the growth of cells and stimulated the healing of the skin, which was improved by the use of cells.

Development of a new nanofiber scaffold for use with stem cells in a third degree burn animal model.

The combination of mesenchymal stem cells (MSCs) and nanotechnology to promote tissue engineering presents a strategy for the creation of new substitutes for tissues. Aiming at the utilization of the scaffolds of poly-d,l-lactic acid (PDLLA) associated or not with Spirulina biomass (PDLLA/Sp) in skin wounds, MSCs were seeded onto nanofibers produced by electrospinning. These matrices were evaluated for morphology and fiber diameter by scanning electron microscopy and their interaction with the MSCs by confocal microscopy analysis. The biomaterials were implanted in mice with burn imitating skin defects for up to 7 days and five groups were studied for healing characteristics. The scaffolds demonstrated fibrous and porous structures and, when implanted in the animals, they tolerated mechanical stress for up to two weeks. Seven days after the induction of lesions, a similar presence of ulceration, inflammation and fibrosis among all the treatments was observed. No group showed signs of re-epithelization, keratinization or presence of hair follicles on the lesion site. In conclusion, although there was no microscopical difference among all the groups, it is possible that more prolonged analysis would show different results. Moreover, the macroscopic analysis of the groups with the scaffolds showed better cicatrization in comparison with the control group.