DEXTRAN-BASED SYSTEMS FOR BIOMEDICAL USE: SYNTHESIS, CROSSLINKING AND CHARACTERIZATION

In the last decades, natural polysaccharides have gained great interest in cosmetics, pharmaceutical, and biomedical applications. Chitosan, alginate, hyaluronan, gellan gum, and dextran are the most used polysaccharides as biomaterials. In recent years, dextran-based materials were developed for drug delivery use, column chromatography application, and cell culture technology. The dextran macromolecules show high resistance to protein adsorption due to their hydrophilicity. This is an important property required by implantable medical devices and drug or protein-targeting carriers, so dextran-based materials are suitable for the coating of biomedical implants and drug delivery systems. Polyelectrolytes such as chitosan, polyallylamine, polystyrene sulfonate, and polyacrylic acid, are commonly used for layer-by-layer coating techniques. In this work, new materials based on dextran methacrylate (DexMA) and polyacrylic acid (PAA) were developed to obtain bioartificial materials that combine polyelectrolyte properties with high anti-fouling characteristics due to polysaccharide moieties. DexMA/PAA systems were prepared with different weight ratios and crosslinked by UV and thermal treatments. The hydrogels obtained were characterized by a morphological (SEM) and physico-chemical (FT-IR, DSC, TGA) analysis before and after the crosslinking. Swelling and mass loss tests were also performed. Samples showed good chemical homogeneity due to molecular interactions between DexMA and PAA. Untreated samples had a dense structure, on the contrary, the crosslinked samples showed an inhomogeneous porosity. Concerning water stability, the crosslinking treatments increased this property. The highest stability in water was shown by DexMA/PAA samples photo-crosslinked by UV at 256 nm followed by thermal treatment.