One-step preparation of nano-in-micro poly(vinyl alcohol) embolic microspheres and used for dual-modal T/T-weighted magnetic resonance imaging.

It is crucial to develop dual or multi-modal self-imaging embolic microspheres to evaluate the effects of transcatheter arterial embolization therapy of tumor. However, the preparation of such hybrid microspheres always involved in multiple steps or complicated conditions. Here, poly(vinyl alcohol) (PVA) hybrid microspheres with dual-modal T/T-weighted magnetic resonance imaging (MRI) have been prepared based on microfluidic technique in one step. GdO and FeO nanoparticles with a size of ~5 nm act as T- and T-weighted MRI contrast agents, respectively, which are simultaneously in-situ synthesized in the PVA matrix via the reaction of metal ions and alkali with PVA chains as a soft template. Meanwhile, these metallic-oxide nanoparticles act as cross-linker to gelatinize the PVA droplets to obtain nano-in-micro PVA microspheres in one step. This procedure is simple, economic and feasible. The obtained nano-in-micro PVA microspheres show good magnetothermal effect, enhanced T- and T-weighted MRI and embolization effect.