Modification of Polysaccharides with Phenols for Hydrogels Formation and Electrospinnig

Abstract

Carboxymethylcellulose (CMC) and alginate (ALG) are water-soluble polysaccharides used in food and cosmetics industry. They have big potential for use in pharmaceutical products due to their high biocompatibility, biodegradibility, low immunogenicity and low price. When crosslinked they can absorb large amounts of water and swell to form hydrogels with great physical properties. The need for new biomaterials and hydrogels is growing daily, due to their use in tissue engineering, drug delivery and cell and enzyme immobilization studies. In this study we modified ALG and CMC, in order to get a cross-linkable polymer that can make hydrogels by chemical and enzymatic means. After periodate oxidation we obtained polysaccharides with different degrees of oxidation: 2.5, 5, 10, 15 and 20 mol%. Further modification using reductive amination in the presence of different phenolic compounds like tyramine, was done. This modification was confirmed by UV–VIS and FT-IR spectroscopy, while concentration of phenol and ionizable groups was determined using absorbance at 275 nm and acid–base titration. All CMC and AlG tyramines were able to form hydrogels after crosslinking with horse radish peroxidase (HRP) and hydrogen peroxide. Both derivatives have been successfully electrospun and crosslinked afterwards. Due to the introduction of amino groups and decrease in molecular weight, they were significantly more soluble in water up to 30 % (w/w) compared to native polysaccharides and their electrospinability also improved. We aim to make nanofibers using tyraminepolysaccharides that will be more stable in cell culture media after cross-linking covalently and with calcium/barium ions. Diameter of nanofibers was determined by scanning electron microscopy (SEM). Cross-linked nanofibers that we obtained will be used for tissue engineering of blood vessels.