Horseradish peroxidase-catalyzed crosslinking injectable hydrogel for bone repair and regeneration

In clinical practice, addressing severe bone defects resulting from trauma, tumors, infections or congenital disorders remains a challenge in the surgical domain. Although bone tissue has a certain capacity for self-repair, artificial substitute materials of bone are still required to facilitate the repair, especially for large-scale bone defects. At present, tissue engineering-related materials that mimic the structure, mechanical properties, and biological characteristics of natural bone have been widely used for addressing bone defects and promoting in situ bone regeneration. Hydrogels that emulate the properties of the extracellular matrix are prevalent materials in bone tissue engineering, with a particular emphasis on those crosslinked through HRP-mediated, which have garnered considerable interest due to their high efficiency of preparation, mild reaction conditions, controllable properties, and excellent biocompatibility. However, the suboptimal osteogenic capability inherent in HRP-mediated crosslinked hydrogels necessitates the integration of additional osteogenic activity materials, such as biological calcium phosphates, biomimetic scaffolds, growth factors, synthetic peptides, and nanomaterials, to bolster the hydrogel scaffolds' osteogenic potential. This manuscript provides a concise overview of the standard methodologies for crafting injectable hydrogels, highlighting the HRP catalytic reaction mechanism, and strategies for modulating hydrogel attributes. Furthermore, this paper delves into the recent advancements in HRP-mediated crosslinked hydrogel scaffolds, highlighting their role in bone defect repair within the realm of bone tissue engineering. These insights establish a robust foundation for the innovation, development, and clinical application of bone tissue substitutes that prioritize biosafety.