In
cancer therapy, a promising treatment option to accomplish a high
tumor-to-normal-tissue ratio is endovascular intervention with microsized particles, such as
embolotherapy. In this study,
alginate microspheres (ams) were prepared with the JetCutter technique, which is based on cutting a
sodium alginate solution jet stream into small droplets of uniform size which are then cross-linked with different
lanthanides or
iron-III, resulting in
microspheres of a predefined size which can be visualized by magnetic resonance imaging (MRI). The
microspheres were investigated for their size and morphology (light microscopy and scanning electron microscopy analysis),
cation content and MRI properties. The
lanthanide-ams formulations, with a uniform size of 250 μm and a
cation content between 0.72-0.94%, showed promising results for MR imaging. This was further demonstrated for Ho(3+)-cross-linked
alginate microspheres (Ho(3+)-ams), the most potent
microsphere formulation with respect to MR visualization, allowing single sphere detection and detailed
microsphere distribution examination. Intravascular infusion of Ho(3+)-ams by catherization of ex vivo rabbit and porcine liver tissue and assessment of the procedure with MRI clearly showed accumulation and subsequently embolization of the targeted vessels, allowing accurate monitoring of the
microsphere biodistribution throughout the tissue. Therefore, the different
alginate-
lanthanide microsphere formulations developed in this study show great potential for utilization as image-guided
embolotherapy agents.