Magnetically driven nanoparticles: ¹⁸ FDG-radiolabelling and positron emission tomography biodistribution study

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Medical Imaging

Background:

• Superparamagnetic iron oxide nanoparticles (SPIONs) are promising for medical imaging and targeted therapies.
• Improving SPIONs' ability to reach specific tissues, especially outside blood vessels, is crucial for therapeutic advancements.
• External magnetic fields offer a non-invasive method to guide SPIONs' biodistribution.

Purpose of the Study:

• To assess the spatial distribution of magnetically-guided, radiolabeled SPIONs in vivo using microPET/CT.
• To evaluate the efficacy of external magnetic fields in concentrating SPIONs within a target tissue.
• To demonstrate the utility of multimodal imaging for assessing SPIONs' biodistribution relative to local anatomy.

Main Methods:

• SPIONs were radiolabeled using 18F-2-fluoro-2-deoxyglucose via chemoselective oxime formation.
• MicroPET/CT imaging was employed to track radiolabeled SPIONs in a mouse thigh model after intravenous administration.
• A permanent magnet was applied to the skin to investigate its effect on SPIONs' localization.

Main Results:

• MicroPET/CT successfully visualized and quantified the accumulation of radiolabeled SPIONs in vivo.
• The application of an external magnet demonstrated a clear localizing effect on SPIONs within the target tissue.
• Multimodal 3D imaging provided anatomical context for SPIONs' biodistribution and magnetic targeting.

Conclusions:

• MicroPET/CT is a viable method for quantitatively assessing SPIONs' in vivo biodistribution and concentration at low levels.
• External magnetic fields can effectively guide SPIONs to specific anatomical regions, enhancing targeted delivery.
• This multimodal imaging approach provides valuable insights for developing SPION-based diagnostic and therapeutic strategies.