Corrugated-Surface Goethite Nanoparticles with Reduced Magnetization and Increased Surface Area for Enhanced T₁ MRI...

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Imaging

Background:

• Gadolinium-based contrast agents (GBCAs) pose safety risks like nephrogenic systemic fibrosis.
• Conventional iron oxide nanoparticles (IONPs) often cause negative T2 contrast, complicating MRI interpretation.
• There is a critical need for safer, positive-contrast MRI agents with optimized relaxivity.

Purpose of the Study:

• To develop novel corrugated-surface iron oxide (COSIO) nanoparticles for improved T1-weighted MRI.
• To investigate the impact of nanoscale morphology and reduced magnetization on relaxivity.
• To evaluate the in vivo performance of COSIO compared to clinical GBCAs.

Main Methods:

• COSIO nanoparticles synthesized via a two-step seed-conversion process using Fe3S4 intermediates.
• Oxidative transformation of intermediates into goethite (α-FeO(OH)).
• Characterization of nanoparticle morphology, magnetization, and relaxivity (r1, r2).

Main Results:

• COSIO nanoparticles exhibited reduced magnetization and a corrugated surface, enhancing water accessibility.
• These properties led to lower transverse relaxivity (r2) and increased longitudinal relaxivity (r1).
• In vivo studies showed COSIO outperformed Magnevist in tumor and vascular imaging with prolonged retention and sharp delineation.

Conclusions:

• Nanoscale morphological control is crucial for developing effective iron-based T1 MRI contrast agents.
• COSIO nanoparticles represent a promising safer alternative to GBCAs for T1 MRI.
• The corrugated structure and optimized relaxivity of COSIO enable superior positive-contrast imaging.