A Radiopaque and Thermoresponsive Nanogel-Based Pickering Emulsion for Permanent Arterial Embolization

The development of liquid embolic agents has significantly advanced the field of transcatheter arterial embolization (TAE). Conventional solid embolic agents, such as gelatin sponges or poly-(vinyl alcohol) (PVA), are limited by their lack of intrinsic radiopacity and reliance on lipiodol, necessitating a cumbersome two-step embolization process. Consequently, a critical need exists for embolic materials that combine intrinsic imaging functionality with enhanced biocompatibility to advance clinical outcomes. We have developed a novel liquid embolic material based on poly-(N-isopropylacrylamide)-co-acrylic acid nanogels (PNAs). Mixing PNAs with lipiodol using a medical three-way stopcock yields a thermosensitive lipiodol-based gel emulsion (TLGE). This material exhibits excellent temperature sensitivity and biocompatibility. Notably, the TLGE demonstrates injectable fluidity and sufficient X-ray contrast in an ex vivo decellularized liver model. This embolization technique requires only a single injection and allows for rapid mixing, offering significant practical advantages in the clinic. Digital subtraction angiography (DSA) facilitates intraoperative imaging and real-time monitoring of the embolization process, aiding in the prevention of nontarget embolization and ensuring precise treatment. In a preclinical study, following the embolization of the right renal artery in New Zealand rabbits, a 42-day observation period revealed no instances of vessel recanalization or damage to nontarget organs. Consequently, this innovative temperature-sensitive material demonstrates significant potential for clinical application in TAE procedures.