Navegando por Palavras-chave "Dermoepidermal Substitute"

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    Desenvolvimento e caracterização de scaffolds porosos de quitosana visando aplicações biomédicas
    (Universidade Federal de São Paulo (UNIFESP), 2019-03-28) Ernesto, Julia Vaz [UNIFESP]; Lopes, Patricia Santos [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The development of scaffolds, obtained from biodegradable materials, is a point of great interest in tissue bioengineering. A bioactive material is considered a cell biocondutor when it acts as a temporary fill element guiding the local cellular activity. Chitosan is a biomaterial with several biological properties that allow the elaboration of a scaffold with satisfactory qualities, presenting coagulant and analgesic effect and is biocompatible and biodegradable. Such qualities conduct the use of the same as three-dimensional support aimed at restoration or reconstitution of tissues. Patients who present the clinical condition of severe skin lesion may opt for the application of skin substitutes or dressings developed from biomaterials. The possible use of these bio-curatives provides a possibility of an accessible and effective treatment option. In this context, a biomaterial with adequate properties to be used as cell growth support was developed. The method consisted of preparing a dispersion of 2% (w / v) chitosan in acetic acid, followed by freezing and freeze-drying. Some samples were kept chemically unchanged and used as crosslinker control, and others were crosslinked with 0.01 mol / L epichlorohydrin for 24 hours being washed and re-frozen and lyophilized. Intercalated to this process, a scaffold neutralization procedure was carried out, resulting in crosslinking by ionic interactions in the polymer network, and characteristics as promising as those of the chemically crosslinked with epichlorohydrin. Scanning electron microscopy showed that the porous morphology of crosslinked chitosan scaffolds promoted controlled formation of the polymer network, conferring properties such as adequate vapor permeability (on average, 107 g.mm/dia.m².kPa), adequate permeation to simulated fluid between 2000 and 2500g / m².day and porosity with interconnection which allows fluid absorption capacity above 900%. The crosslinking processes also favored a better mechanical resistance to the handling, corroborated by the biodegradation tests. In the biological field, although no inhibitory activity was observed for growth of microorganisms in the plates, the samples did not allow the permeation of these to the internal environment, forming an efficient barrier against contaminations. They do not present cytotoxicity, guaranteeing safety and confirming the biocompatibility of the frameworks, and allowed satisfactory cell adhesion and proliferation. Results of the tests showed that the crosslinked framework with epichlorohydrin and treated with the sodium bicarbonate neutralizer have statistically equivalent and satisfactory characteristics to be used as a bio-curative, and it is possible to obtain a functional and equivalent dermo-epidermal equivalent for treatment of different pathologies In addition it can provide an efficient and practical system for in vitro toxicological evaluation, replacing the use of animals in the research of pharmaceuticals and cosmetics fields.