Inner structure- and surface-controlled hollow MnO nanocubes for high sensitive MR imaging contrast effect

Area of Science:

• Nanomaterials Science
• Biomedical Imaging
• Materials Chemistry

Background:

• Developing effective T1 Magnetic Resonance Imaging (MRI) contrast agents is crucial for improving diagnostic accuracy.
• Manganese oxide (MnO) nanoparticles offer potential as MRI contrast agents due to their paramagnetic properties.
• Enhancing water solubility and accessibility of MnO to water molecules is key for optimizing relaxivity.

Purpose of the Study:

• To fabricate water-soluble manganese oxide (MnO) nanocubes with modified surfaces.
• To engineer hollow MnO structures to enhance water molecule accessibility and MRI contrast.
• To evaluate the T1 MRI contrast effect and biocompatibility of modified MnO nanocubes.

Main Methods:

• Fabrication of MnO nanocubes with surface modification via ligand encapsulation or exchange.
• Creation of hollow MnO structures through acidic etching (phthalate buffer, pH 4.0).
• Assessment of T1-weighted MR contrast effects and relaxivity (r1) using four types of modified MnO nanocubes (MnOEn, MnOEnHo, MnOEx, MnOExHo).

Main Results:

• Surface modification and hollow structures significantly increased MnO interaction with water molecules.
• MnOExHo demonstrated a high T1 relaxivity (r1) of 6.02 mM⁻¹s⁻¹, approximately 1.5 times higher than commercial agents.
• All tested MnO nanocubes exhibited sufficient MR contrast effects and good biocompatibility.

Conclusions:

• Surface-functionalized and hollow MnO nanocubes serve as effective T1 MRI contrast agents.
• MnOExHo shows superior performance, enhancing diagnostic visibility at disease sites.
• These findings highlight the potential of engineered MnO nanocubes for advanced medical imaging applications.