New biodegradable dextran-​based hydrogels for protein delivery: Synthesis and characterization

A new derivative of dextran grafted with polyethylene glycol methacrylate through a carbonate bond (DEX–PEG–MA) has been synthesized and characterized. The photo-crosslinking reaction of DEX–PEG–MA allowed the obtainment of biodegradable networks tested for their mechanical and release properties. The new hydrogels were compared with those made of dextran methacrylate (DEX–MA), often employed as drug delivery systems of small molecules. The inclusion of PEG as a spacer created additional interactions among the polymeric chains improving the extreme fragility and lack of hardness typical of gels made of DEX–MA. Moreover, the different behavior in terms of swelling and degradability of the networks was able to affectthe release of a model macromolecule over time, laking DEX–PEG–MA matrices suitable candidates for the delivery of high molecular weight peptides. Interestingly, the combination of the two dextran derivatives showed intermediate ability to modulate the release of high molecular weight macromolecules.