131I-Labeled Silk Fibroin Microspheres for Radioembolic Therapy of Rat Hepatocellular Carcinoma

Transarterial radioembolization (TARE) is a promising technology in hepatocellular carcinoma (HCC) therapy, which utilizes radionuclide-labeled microspheres to achieve arterial embolization and internal irradiation. However, the therapeutic effect of liver cancer can be affected by low radionuclide labeling rate and stability, as well as poor biocompatibility, and non-biodegradability of microspheres. Here, 131I-labeled silk fibroin microspheres (131I-SFMs) were developed as radioembolization material for effective TARE therapy against HCC. Silk fibroin rich in 10.03% of tyrosine was extracted from silkworm cocoons and then emulsified and genipin-crosslinked to prepare SFMs. SFMs show a good settlement rate, biodegradability, hemocompatibility, and low cytotoxicity. Afterward, 131I-SFMs were obtained by radiolabeling 131I onto the SFMs through the chloramine-T method. 131I-SFMs possess a high 131I labeling rate of over 84% and good radioactive stability and are thus conducive to internal radiotherapy. Significantly, 131I-SFMs with diameters around 11 μm were successfully radioembolized at the hepatic artery. 131I-SFMs were diffused in the liver, indicating the favorable biodistribution and biosafety in vivo. Based on the combination of embolization and local radiotherapy, the administration of 131I-SFMs shows a favorable inhibitive effect against the progression of HCC. Overall, the newly developed 131I-SFMs as radioembolization microspheres provide a promising application for effective TARE therapy against liver cancer.