Effect of crosslinking agent to design nanostructured hyaluronic acid-based hydrogels with improved relaxometric properties.

Nowadays, natural polysaccharides have given promising results as drug carriers. Among them, the hydrogels, thanks to their versatile properties, have been produced and engineered at the nano-scale in order to develop nanovectors for diagnostic and therapeutic purposes. Here, we investigate the contribution that a natural biopolymer, hyaluronic acid (HA), can give to the field of Magnetic Resonance Imaging (MRI). In addition, we study the relaxometric properties of crosslinked and non-crosslinked hydrogel networks and outline the impact of both HA concentration and crosslinker, Divinyl Sulfone (DVS), on the relaxivity of aqueous polymer solutions, even in the absence of Contrast Agents (CAs). Results show that proper HA concentration and the presence of the crosslinking agent can enhance the longitudinal relaxation time of the surrounding water, even in the absence of CAs. These findings could inspire the design of novel nanostructured hydrogels with enhanced relaxometric properties for MRI applications and not only.