Biodegradable 131 Iodine-Labeled Microspheres: Potential Transarterial Radioembolization Biomaterial for Primary Hepatocellular Carcinoma Treatment.

Transarterial radioembolization with radionuclide-labeled microspheres is successfully used in hepatocellular carcinoma (HCC) treatment, but the non-biodegradability and rapid settlement of the microsphere material are associated with unsatisfied distribution and unable for multiple administrations. In this study, a novel biodegradable chitosan-collagen composite microsphere (CCM) with ideal settlement rate is prepared. The Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) results indicate CCMs have desirable shapes with diameters around 10 µm, and considerable biodegradability within 12 weeks. These CCMs are successfully radiolabeled with 131 I and processed efficiency of 70.4 MBq mg-1 of microspheres as well as favorable stability in vitro. Then, 131 I-CCMs are injected into rats with orthotopic HCC via the hepatic artery which effectively improves the median overall survival from 19 to 44 days (p < 0.05). Single photon emission computed tomography (SPECT/CT) imaging and immunohistochemical analysis indicate well-localized biodistribution and consistent stability of 131 I-CCMs in the liver over 28 days. Magnetic resonance imaging (MRI) and gross specimens monitoring confirm the inhibited tumor growth after 131 I-CCMs treatment. In conclusion, these biodegradable 131 I-CCMs exhibit optimal radiolabeling efficiency, stability, and favorably radioembolization effect for orthotopic HCC in a rodent model, suggesting potential for interventional cancer therapy.