Carbon-based biodegradable composite microspheres enabling magnetic–thermal coupling for chemoembolization

Carbon-containing polymer composites integrated with metal oxide nanoparticles offer opportunities to regulate thermal and magnetic responses through interfacial interactions. This study develops Fe3O4/polycaprolactone (PCL) composite microspheres constructed from a carbon-containing biodegradable matrix, enabling magnetically guided chemoembolization and hyperthermia. The microspheres are fabricated via a water-in-oil-in-water emulsion method, resulting in a controlled size distribution (350–550 μm) suitable for embolization. Fe3O4 nanoparticles are incorporated to confer magnetic responsiveness and photothermal activity, while the carbon-rich polymer matrix (PCL) provides biodegradability and cost-effectiveness. Comprehensive physicochemical characterization confirms the successful integration of Fe3O4 and homogeneous morphology of the microspheres. The resulting microspheres exhibit adequate magnetization (6.6 emu g− 1), photothermal heating capability under near-infrared laser irradiation (ΔT = 4.5 °C at 50 mg mL− 1) and dose-dependent embolization behavior in a phantom model. Drug release experiments reveal a biphasic release profile, with an initial burst release (cumulative release of ~ 13% within 3 h), followed by sustained release reaching approximately 19%. Thermal analysis revealed a narrowing of the derivative thermogravimetry (DTG) peak relative to neat PCL, suggesting synchronized degradation behavior associated with carbon–metal oxide interfacial interaction. These findings demonstrate that Fe3O4/PCL composite system exhibits coordinated magnetic–thermal functionality governed by the carbon-containing polymer matrix and its interfacial interaction with iron oxide nanoparticles.