Microarchitectonics of Gel Microspheres for Arterial Embolization with High Drug Loading and Digital Subtraction Angiography Real-Time Visibility

Gel microspheres have been widely employed in transcatheter arterial chemoembolization (TACE) for the clinical treatment of cancer and related diseases. However, multifunctional microspheres that simultaneously offer a high drug-loading capacity and real-time imaging for precise embolization remain limited. In this study, we developed the microarchitectonics of a multifunctional microsphere composed of sulfonated poly(vinyl alcohol) (PVA), sodium alginate (SA), and barium sulfate (BaSO 4 ), designated as BaSO 4 @PAS@DOX. Owing to the enhanced ionization properties of the matrix, the microspheres exhibit exceptional loading efficiency for cationic chemotherapeutics such as doxorubicin (DOX), achieving a high drug concentration of up to 101 mg/mL, along with pH-responsive release behavior. Additionally, the in situ formation of uniformly dispersed BaSO 4 nanocrystals within the microspheres enables strong digital subtraction angiography (DSA) contrast, facilitating real-time visualization during embolization. In vitro assessments demonstrated excellent biocompatibility and sustained drug release. In a rabbit auricular central artery embolization model, the microspheres enabled precise, image-guided vascular occlusion and induced localized tissue necrosis. These results highlight the potential of BaSO 4 @PAS@DOX microspheres as a promising platform for next-generation TACE applications.