Transcatheter embolization is a minimally invasive procedure that uses embolic agents to intentionally block diseased or injured blood vessels for therapeutic purposes. Embolic agents in clinical practice are limited by recanalization, risk of non‐target embolization, failure in coagulopathic patients, high cost, and toxicity. Here, a decellularized cardiac extracellular matrix (ECM)‐based nanocomposite hydrogel is developed to provide superior mechanical stability, catheter injectability, retrievability, antibacterial properties, and biological activity to prevent recanalization. The embolic efficacy of the shear‐thinning ECM‐based hydrogel is shown in a porcine survival model of embolization in the iliac artery and the renal artery. The ECM‐based hydrogel promotes arterial vessel wall remodeling and a fibroinflammatory response while undergoing significant biodegradation such that only 25% of the embolic material remains at 14 days. With its unprecedented proregenerative, antibacterial properties coupled with favorable mechanical properties, and its superior performance in anticoagulated blood, the ECM‐based hydrogel has the potential to be a next‐generation biofunctional embolic agent that can successfully treat a wide range of vascular diseases.

Endovascular embolization to treat vascular hemorrhage involves pushing coil‐shaped metal wires into the artery repeatedly until they are densely packed to slow the blood flow and clot. However, coil embolization is associated with high rebleeding rates, unpredictable economics and, most importantly, they rely on the patient's ability to make a clot. These issues are exacerbated when the patient is anticoagulated or coagulopathic. A novel bioengineered tantalum‐loaded nanocomposite hydrogel for gel embolic material (Ta‐GEM) that can be rapidly delivered using clinical catheters for instant hemostasis regardless of the coagulopathic state is reported. Ta‐GEM formulation is visible by most of the clinically available imaging modalities including ultrasound, computed tomography, magnetic resonance imaging, and fluoroscopy without significant artifact. In addition, Ta‐GEM can be retrieved, allowing temporary vascular occlusion, and it can be used to rescue cases of failed coil embolization. Ta‐GEM occlusion of first‐order arteries such as the renal artery and iliac artery in a swine model is found to be safe and durable; by 28 days, 75% of the injected Ta‐GEM in the arterial lumen is replaced by dense connective tissue. Altogether, this study demonstrates that Ta‐GEM has many advantages over the current technologies and has potential applications in clinical practice.

Embolization is a catheter‐based minimally invasive procedure that deliberately occludes diseased blood vessels for treatment purposes. A novel silk‐based embolic material (SEM) that is developed and optimized to provide tandem integration of both embolization and the delivery of therapeutics is reported. Natural silk is processed into fibroin proteins of varying lengths and is combined with charged nanoclay particles to allow visibility and injectability using clinical catheters as small as 600 μm in diameter at lengths >100 cm. SEMs loaded with fluorochrome labeled bovine albumin and Nivolumab, which is among the most used immunotherapy drugs worldwide, demonstrate a sustained release profile in vitro over 28 days. In a porcine renal survival model, SEMs with labeled albumin and Nivolumab successfully embolize porcine arteries without recanalization and lead to the delivery of both albumin and Nivolumab into the interstitial space of the renal cortex. Mechanistically, it is shown that tissue delivery is most optimal when the internal elastic membrane of the embolized artery is disrupted. SEM is a potential next‐generation multifunctional embolic agent that can achieve embolization and deliver a wide range of therapeutics to treat vascular diseases including tumors.

Percutaneous locoregional therapies (LRTs), such as thermal ablation, are performed to limit the progression of hepatocellular carcinoma (HCC) and offer a bridge for patients waiting for liver transplantation. However, physiological challenges related to tumor location, size, and existence of multiple lesions as well as safety concerns related to potential thermal injury to adjacent tissues may preclude the use of thermal ablation or lead to its failure. Here, we showed a successful injection of an ionic liquid into tissue under image guidance, ablation of tumors in response to the injected ionic liquid, and persistence (28 days) of coinjected chemotherapy with the ionic liquid in the ablation zone. In a rat HCC model, the rabbit VX2 liver tumor model, and 12 human resected tumors, injection of the ionic liquid led to consistent tumor ablation. Combining the ionic liquid with the chemotherapy agent, doxorubicin, resulted in synergistic cytotoxicity when tested with cultured HCC cells and uniform drug distribution throughout the ablation zone when percutaneously injected into liver tumors in the rabbit liver tumor model. Because this ionic liquid preparation is simple to use, is efficacious, and has a low cost, we propose that this new LRT may bridge more patients to liver transplantation.