Engineered Matrices Based on Gellan Gum and Biocompatible Synthetic Polymers for the Release of Molecules with Antioxidant Activity

Over the past few decades, microbial polysaccharides hydrogels have been used in the field of tissue regeneration due to their ability to mimic the physical-chemical and mechanical characteristics of the extracellular matrix. Gellan gum, an anionic heteropolysaccharide that can form hydrogel in presence of di or trivalent cations, has interesting properties in terms of biodegradability, biocompatibility and the ability to integrate with surrounding tissues. However, it also has some limitations such as the lack of specific sites within the polysaccharide chains for cell recognition and adhesion, high hygroscopicity and limited mechanical properties. Gellan gum has also been proposed for application in the field of controlled release of bioactive molecules; the bio-inert nature of gellan gum makes it suitable for the encapsulation of biomolecules, drugs, enzymes and nutraceutical formulations. Furthermore, the anionic nature of this polysaccharide makes it suitable as a pH sensitive drug delivery system. This work deals with the production and characterization of hydrogels based on gellan gum and polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) for the creation of matrices, containing curcumin as an antioxidant agent, having a micro-engineered surface obtained using micro-molded silicone molds. The properties of gellan hydrogels mixed with PVA or PVP containing curcumin, before and after crosslinking with Ca2+ ions, were investigated. The highest curcumin solubility was observed in PVP solution (0.0156 mg/mL) as compared to PVA solution (0.0074 mg/mL). The contribution of gellan hydrogels mixed with PVA or PVP to the antioxidant capacity of curcumin, expressed as % inhibition, was 22% and 25%, respectively.