An Intravascular Magnetic Catheter Enables the Retrieval of Nanoagents from the Bloodstream.

The clinical adoption of nanoscale agents for targeted therapy is still hampered by the quest for a balance between therapy efficacy and side effects on healthy tissues, due to nanoparticle biodistribution and undesired drug accumulation issues. Here, an intravascular catheter able to efficiently retrieve from the bloodstream magnetic nanocarriers not contributing to therapy, thus minimizing their uncontrollable dispersion and consequently attenuating possible side effects, is proposed. The device consists of a miniature module, based on 27 permanent magnets arranged in two coaxial series, integrated into a clinically used 12 French catheter. This device can capture ≈94% and 78% of the unused agents when using as carriers 500 and 250 nm nominal diameter superparamagnetic iron oxide nanoparticles, respectively. This approach paves the way to the exploitation of new "high-risk/high-gain" drug formulations and supports the development of novel therapeutic strategies based on magnetic hyperthermia or magnetic microrobots.