Single-Atom Gd Nanoprobes for Self-Confirmative MRI with Robust Stability

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Imaging

Background:

• Gadolinium (Gd)-based complexes are widely used as contrast agents (CAs) in magnetic resonance imaging (MRI).
• Existing Gd-based CAs face challenges including potential safety concerns and inadequate tumor targeting.
• There is a need for advanced MRI CAs with improved efficacy and safety profiles.

Purpose of the Study:

• To construct single-atom Gd nanoprobes as a safer and more effective alternative to conventional Gd-based MRI CAs.
• To achieve dual-mode T1/T2 imaging with enhanced stability and tumor targeting capabilities.
• To explore a novel design protocol for developing next-generation MRI contrast agents.

Main Methods:

• Single-atom Gd anchored on a nitrogen-doped carbon matrix (Gd-Nx C) was synthesized using a spatial-confinement method.
• Controllable chemical etching was employed to create fully etched bowl-shape Gd-Nx C (feGd-Nx C) nanostructures.
• The r1 and r2 relaxivity values, stability, and tumor targeting ability of the feGd-Nx C nanoprobes were evaluated.

Main Results:

• The single-atom Gd nanoprobes exhibited significantly higher r1 (34.2 mM-1 s-1) and r2 (80.1 mM-1 s-1) values compared to commercial Gd CAs at 3 T.
• The feGd-Nx C nanoprobes demonstrated excellent kinetic inertness and thermal stability, with no significant Gd3+ leaching observed over two months.
• The nanostructures facilitated maximized Gd3+ site exposure and enabled self-confirmative diagnosis through dual-mode MRI.

Conclusions:

• Single-atom Gd nanoprobes represent a promising new class of MRI contrast agents with superior performance and safety.
• The developed feGd-Nx C nanostructures offer a creative design protocol for advanced MRI CAs.
• This approach holds potential for improving diagnostic accuracy and patient outcomes in MRI.