Mussel-inspired tough and dynamic nanocomposite hydrogel based on oxidized sodium alginate and gelatin for protein delivery applications

Abstract

Biomacromolecules based injectable and self-healing hydrogels are promising soft biomaterials with dynamic and reversible features. Yet, it remains a challenge to achieve both high mechanical strength and dynamic behavior. Here, we present a tough dynamic nanocomposite hydrogel (Fe₃O₄/PDA@OSA-l-Gel) fabricated by incorporating polydopamine coated iron oxide nanoparticles (Fe₃O₄/PDA NPs) into dynamically crosslinked biomacromolecular networks of oxidized sodium alginate (OSA) and gelatin (Gel) in the presence of borax. The loading of Fe₃O₄/PDA NPs significantly enhances the mechanical properties of dynamic nanocomposite hydrogel exhibiting excellent injectable and self-healing properties. The synergistic effect of multiple dynamic chemical bonds (e.g., imine bond, borate ester bond) and physical interactions (e.g., electrostatic interaction, hydrogen bond) that enable excellent mechanical properties (3.78 MPa compressive strength, 674.72 J/m³ energy dissipation and 109.1 kJ/m³ toughness). Fe₃O₄/PDA NPs play the role of killing two birds with one stone, i.e., act as a nano-crosslinker to enhance mechanical properties of the dynamic nanocomposite hydrogel, and as a carrier for sustained protein release. Furthermore, the dynamic nanocomposite hydrogel exhibits good hemocompatibility and cytocompatibility. This work highlights the novel strategy for doping mussel inspired nanoparticles into dynamic hydrogel networks to enhance mechanical properties and sustain protein release.

Keywords: Dynamic nanocomposite hydrogel; Mechanical strength; Multiple reversible interactions; Mussel inspiration; Protein release.