Durable Radiopaque Embolic Hydrogels via Iodinated Monomer Copolymerization for Transarterial Chemoembolization

ABSTRACT Radiopacity is essential for embolic hydrogels used in transarterial chemoembolization (TACE), yet physically mixed iodinated contrast agents can readily diffuse from hydrated networks, causing rapid signal loss. To address this limitation, a copolymerizable iodinated methacrylate monomer (IMM) is synthesized and incorporated into an epirubicin‐loaded poly(lactic‐co‐glycolic acid) (PLGA) microsphere/poly(ethylene glycol) diacrylate (PEGDA) composite hydrogel to construct an intrinsically radiopaque embolic material. Structural characterization supports IMM formation. Increasing IMM content increases swelling, while all hydrogels retain elastic‐dominated rheological behavior. The storage modulus ( G ′) exceeds the loss modulus ( G ″) over 0.1–10 Hz. The compressive moduli of IMM‐containing hydrogels range from 124.9 to 162.8 kPa. Compared with physically mixed iopromide (I‐370), IMM‐containing hydrogels exhibit markedly improved radiopacity retention. After 36 h in phosphate‐buffered saline, the computed tomography (CT) attenuation of the iopromide‐containing hydrogel decreases from 700.94 to 2.18 Hounsfield units (HU), whereas that of the hydrogel containing 180 mg IMM decreases only slightly from 755.21 to 714.98 HU. Moreover, all IMM‐containing hydrogels show cumulative radiopaque‐component elution ratios below 7% after 168 h. These results demonstrate that copolymerizable incorporation of iodinated functionality effectively improves radiopacity retention and provides a practical strategy for preparing intrinsically imageable PEGDA‐based hydrogel embolic materials.