Recent Progress in Advanced Hydrogel-Based Embolic Agents: From Rational Design Strategies to Improved Endovascular Embolization.

Transcatheter arterial embolization, a minimally invasive treatment to deliberately occlude the blood vessels, has become a safe and effective procedure for the management of vascular diseases and benign/malignant tumors. Particularly, hydrogel-based embolic agents have garnered much attention because of their potential to address some of the limitations of clinically used embolic agents and can be rationally designed to impart more favorable characteristics or functions. In this review, the recent progress toward the development of polymer-based hydrogels for effective endovascular embolization, including the in situ gelling hydrogels mediated by physically or chemically crosslinking, imageable hydrogels for intraprocedural and postprocedural feedback, use of hydrogels as the drug depot for local delivery of therapeutic drugs, hemostatic hydrogels inducing extrinsic or intrinsic coagulation of blood, stimuli-responsive shape memory hydrogels as the smart embolization devices, and hydrogels incorporating external-stimuli functional materials for multidisciplinary therapy, is systemically summarized. Moreover, the potential considerations of hydrogel-based embolic agents confronted in therapeutic embolization are pointed out. Finally, the perspectives for the development of more effective embolic hydrogels are also highlighted.