A Modular Core-Shell Nanoparticle Platform for Dual-Modal MRI-Luminescence With High Relaxivity

Area of Science:

• Nanotechnology
• Biomedical Imaging
• Materials Science

Background:

• Bimodal imaging agents combining MRI and optical signals offer complementary anatomical and molecular information for improved diagnostic precision.
• Macromolecular MRI agents exhibit higher relaxivities than small-molecule agents due to controlled architectures enhancing Gd(III)-water interactions.
• Previous bimodal macromolecular agents faced challenges in safety (unchelated metals) and reproducible large-scale production.

Purpose of the Study:

• To develop a simple, reproducible method for incorporating both MRI and luminescence agents into nanoparticles.
• To create a tunable platform for dual-modal MRI-luminescence applications with enhanced safety and performance.
• To address limitations of previous bimodal imaging agents, including safety concerns and production reproducibility.

Main Methods:

• Incorporation of isostructural Gadolinium (Gd(III)) and Terbium (Tb(III)) complexes into amphiphilic core-shell block copolymer nanoparticles.
• Utilized a single macrocyclic methacrylate ligand for direct complex incorporation.
• Modular design allowing controlled spatial positioning of MRI (Gd(III)) and luminescence (Tb(III)) agents.

Main Results:

• Achieved high relaxivity of up to 30.2 mM⁻¹s⁻¹ per Gd(III).
• Demonstrated long-lived luminescence (>1.30 ms).
• Successfully created a tunable platform for dual-modal MRI-luminescence applications.

Conclusions:

• The presented method offers a simple, reproducible, and modular approach for synthesizing advanced bimodal imaging agents.
• The developed nanoparticles provide high relaxivity and long-lived luminescence, suitable for dual-modal imaging.
• This platform overcomes previous safety and production challenges, paving the way for improved diagnostic tools.