Novel Silicone-Coated 125I Seeds for the Treatment of Extrahepatic Cholangiocarcinoma

125 I seeds coated with titanium are considered a safe and effective interstitial brachytherapy for tumors, while the cost of 125 I seeds is a major problem for the patients implanting lots of seeds. The aim of this paper was to develop a novel silicone coating for 125 I seeds with a lower cost. In order to show the radionuclide utilization ratio, the silicone was coated onto the seeds using the electro-spinning method and the radioactivity was evaluated, then the anti-tumor efficacy of silicone 125 I seeds was compared with titanium 125 I seeds. The seeds were divided into four groups: A (control), B (pure silicone), C (silicone 125 I), D (titanium 125 I) at 2 Gy or 4 Gy. Their anti-tumour activity and mechanism were assessed in vitro and in vivo using a human extrahepatic cholangiocarcinoma cell line FRH-0201 and tumor-bearing BALB/c nude mice. The silicone 125 I seeds showed higher radioactivity; the rate of cell apoptosis in vitro and the histopathology in vivo demonstrated that the silicone 125 I seeds shared similar anti-tumor efficacy with the titanium 125 I seeds for the treatment of extrahepatic cholangiocarcinoma, while they have a much lower cost.