Multivalent manganese complex decorated amphiphilic dextran micelles as sensitive MRI probes

Area of Science:

• Biomedical Engineering
• Materials Science
• Radiology

Background:

• T1 contrast agents are crucial for Magnetic Resonance Imaging (MRI).
• Manganese(II) complexes offer paramagnetic properties for T1 MRI.
• Developing stable and effective manganese-based contrast agents remains an area of active research.

Purpose of the Study:

• To conjugate manganese(II) onto amphiphilic dextran micelles.
• To evaluate the T1 relaxivity and sensitivity of the novel nanomicelle contrast agent.
• To assess the in vivo vascular enhancement effect and manganese dosage.

Main Methods:

• Amphiphilic dextran micelles were synthesized.
• Manganese(II) was conjugated to the micelles using click chemistry.
• T1 relaxivity measurements were performed.
• In vivo studies were conducted to evaluate vascular enhancement.

Main Results:

• The nanomicelle contrast agent exhibited higher T1 relaxivity (13.3 Mn mmol⁻¹ s⁻¹) compared to free Mn(II) complexes.
• Enhanced sensitivity was observed with the nanomicelle formulation.
• In vivo studies demonstrated a superior and long-acting vascular enhancement effect.
• Effective enhancement was achieved at a low manganese dosage (0.1 Mn mmol kg⁻¹ BW).

Conclusions:

• Conjugating Mn(II) onto amphiphilic dextran micelles via click chemistry yields a highly effective T1 contrast agent.
• The nanomicelle agent offers improved performance and reduced manganese dosage for in vivo MRI.
• This approach presents a promising strategy for developing advanced manganese-based MRI contrast agents.