Design and characterization of polysaccharide hydrogel membranes as drug delivery systems

• Autor(a) principal: Martins, Matilde Taborda
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/161279
• topic: Hydrogel membranes; FucoPol; EPS1; drug delivery systems; biocompatible; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

n this thesis, the preparation and characterization of polysaccharide-based hydrogel membranes (HMs) was conducted using two bacterial polysaccharides, FucoPol and EPS1. FucoPol is an extracellular polysaccharide (EPS) produced by the bacterium Enterobacter A47 being composed of fucose, galactose, glucose and glucuronic acid, and possessing various interesting properties. EPS1 is produced by the marine bacterium Alteromonas macleodii Mo169 being composed of glucuronic acid, mannose, glucose, galacturonic acid, galactose, and glucosamine. The gel-forming capacity of these biopolymers was previously assessed, therefore, the aim of this thesis was to process them into HMs, as well as evaluating the mechanical, rheological and morphological properties of the prepared membranes to assess their suitability for use as drug delivery systems (DDSs). Additionally, for the FucoPol HMs, a biological characterization was conducted, and their drug loading and release properties were also evaluated. Both HMs were prepared by cation mediated gelation with iron. FucoPol HMs were produced using an iron concentration of 1.5 g/L and varying biopolymer contents (1 wt%, 1.75 wt% and 2.5 wt%), while for the EPS1 membranes, different concentrations of biopolymer (0.5 wt%, 1 wt% and 1.5 wt%) and iron (1.5 g/L, 5 g/L and 8.5 g/L) were used. In both cases, three HMs were prepared and characterized. All structures presented high water contents (above 97 wt%), characteristic of hydrogels, and low iron content (below 0.29 wt%). All HMs presented a solid-like behavior, however, the HMs with higher iron and polymer contents presented higher hardness. FucoPol HMs had lower porosity, while the EPS1 HMs had higher swelling degree. FucoPol HMs were demonstrated to be non-cytotoxic for both fibroblasts and THP1 cells, presenting also anti-inflammatory properties. The ability of the FucoPol HMs to load and release drugs was conducted using the HMs with the lower polymer content (HM1) and using two loading methods and two model drugs (caffeine and diclofenac sodium (DS)). It was determined for the soaking method the release was faster and for the mixing method, higher amounts of DS were released from the structure (101± 5.48% of cumulative release) than caffeine (52±4.7% of cumulative release). Both developed hydrogels were demonstrated to possess valuable properties that support their future utilization as biomaterials for the development of biomedical applications, including tissue engineering, drug delivery, amongst others. FucoPol HMs, given their demonstrated biological properties, is of particular interest for such applications.