Fusible and Radiopaque Microspheres for Embolization

In this work, fusible microspheres loaded with radiopaque agents as an embolic agent for transcatheter arterial embolization (TAE) are developed. A poly(ethylene glycol) (PEG) and poly(ε‐caprolactone) (PCL) multi‐block copolymer basing polyurethane (PCEU) is synthesized and fabricated into blank microspheres (BMs). The microspheres are elastic in compression test. A clinical contrast agent lipiodol is encapsulated in the microspheres to receive fusible radiopaque microspheres (FRMs). The sizes of FRMs are uniform and range from 142.2 to 343.1 µm. The encapsulated lipiodol acts as the plasticizer to reduce the melting temperature point (Tm) of PECU microspheres, thus, leading to the fusion of microspheres to exhibit efficient embolization in vivo. The performance of FRMs is carried out on a rabbit ear embolization model. Serious ischemic necrosis is observed and the radiopacity of FRMs sustains much longer time than that of commercial contrast agent Loversol in vivo. The fusible and radiopaque microsphere is promising to be developed as an exciting embolic agent. The fusible and radiopaque microspheres (FRMs) are prepared for transcatheter arterial embolization. A clinical contrast agent, Lipiodol, is encapsulated in the microspheres, making them fusible in physiological environments, contributing to complete ischemic necrosis. Additionally, Lipiodol provides the microspheres with a sustained X‐ray imaging feature, allowing for the monitoring of their location in vivo.