Development of wound healing biomaterials based on bacterial exopolysaccharides

• Autor(a) principal: Ramos, Kleyde Delsy Delgado
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/129170
• topic: Exopolysaccharides; nanoparticles; cytotoxicity; wound healing; biopolymer; biocomposites synthesis; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Currently, biopolymers have aroused great interest mainly in the food, pharmaceutical, cosmetic, and also in the biomedical fields, due to the intelligent and versatile properties that present, namely, biocompatibility, biodegradability, and non-toxicity. In addition to these properties, many polymers have vital characteristics that assist in wound healing processes and, when incorporated into nanoparticles of elements such as silver (Ag), gold (Au), and selenium (Se), further increase the effectiveness of these polymers. Therefore, the main objective of this study was to determine the best conditions for the preparation of biocomposites for application in the treatment of wounds, using different extracellular bacterial polysaccharides (EPSs) (EPS1, EPS2, EPS3, EPS4, and FucoPol) as reducing and stabilizing agents for the synthesis of silver nanoparticles (AgNP), gold (AuNP) and selenium (SeNP). EPSs were characterized as to the composition in sugars and substituting groups, because, depending on the composition, they can interfere in some way in the properties of each one. EPS1 is composed mainly of mannose (56.1% mol), EPS2 and EPS3 are composed mainly of glucose, 67% mol and 39.1% mol, respectively, EPS4 is composed mainly of glucuronic acid (55.9% mol) and FucoPol by fucose (34.9 mol%). Biocomposites were also characterized by UV-vis spectroscopy, FTIR, TGA, XRD, DLS, Zeta potential and ICP. Cytotoxicity and wound healing effect of EPSs and EPS/NPs biocomposites were analyzed in human keratinocyte cells (HaCaT cell line). The samples were tested using a polymer concentration of 62.5 - 1000 mg/L and none of the samples showed cytotoxicity, except for the EPS3/Ag+ biocomposite when tested at a polymer concentration above 125 mg/L, with a content Ag+ above 6.9 mg/L (decreased cell viability by ~91.9%). On the other hand, among all EPSs and their functionalized materials, FucoPol and the biocomposite FucoPol/AgNP exhibited a greater capacity to promote keratinocyte migration in vitro. Although EPS1 did not present wound healing effect, the biocomposites EPS1/AgNP (100 mg/L) and EPS1/AuNP (500 mg/L) showed to promote the migration of HaCaT cells. The results obtained suggest that both FucoPol and the biocomposite FucoPol/AgNP, as well as the biocomposites EPS1/AgNP and EPS1/AuNP, may have potential application in dermo-cosmetics, mainly in wound healing mechanisms.