MRI relaxation properties of water-soluble apoferritin-encapsulated gadolinium oxide-hydroxide nanoparticles

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Radiology

Background:

• Gadolinium-based contrast agents (GBCAs) are widely used in Magnetic Resonance Imaging (MRI).
• Current GBCAs face challenges related to gadolinium (Gd) toxicity and limited relaxivity.
• Apoferritin, a natural protein cage, offers a biocompatible platform for nanoparticle encapsulation.

Purpose of the Study:

• To synthesize and characterize water-soluble gadolinium oxide nanoparticles encapsulated within apoferritin.
• To evaluate the potential of these nanoparticles as novel MRI contrast agents.
• To assess the stability and safety profile of the developed nanoparticles.

Main Methods:

• Synthesis of gadolinium oxide nanoparticles within the apoferritin cavity.
• Characterization of nanoparticle size and morphology using electron microscopy.
• Assessment of gadolinium (Gd) content and stability over time.
• Measurement of NMR longitudinal and transverse relaxivities.

Main Results:

• Water-soluble gadolinium oxide nanoparticles with an average size of 5 nm were successfully prepared within apoferritin.
• Apoferritin demonstrated effective encapsulation, acting as a stable Gd store with minimal leaching after an initial 5% loss.
• The synthesized nanoparticles exhibited NMR longitudinal and transverse relaxivities approximately 10 and 70 times higher, respectively, than clinically approved agents.

Conclusions:

• Apoferritin-encapsulated gadolinium oxide nanoparticles represent a promising new class of MRI contrast agents.
• The enhanced relaxivity and inherent stability of these nanoparticles suggest improved efficacy and reduced toxicity.
• This approach offers a viable strategy for developing next-generation, safer MRI contrast agents.