Magnetically Decorated Multi-Walled Carbon Nanotubes as Dual MRI and SPECT Contrast Agents

Area of Science:

• Nanomedicine
• Biomedical Imaging
• Materials Science

Background:

• Carbon nanotubes (CNTs) are promising nanomaterials for biomedical applications, including drug/gene delivery and imaging.
• Developing dual-modality imaging agents can enhance diagnostic capabilities by combining different imaging techniques.

Purpose of the Study:

• To develop and characterize radio-labeled iron oxide decorated multi-walled CNTs (MWNT) as dual magnetic resonance (MR) and single photon emission computed tomography (SPECT) imaging agents.
• To evaluate the in vivo performance and biodistribution of these hybrid nanomaterials.

Main Methods:

• Synthesis of iron oxide decorated MWNT hybrids via in situ generation.
• Physicochemical characterization using HRTEM, FFT, XRD, and XPS to confirm SPION structure (γ-Fe2O3).
• Radio-labeling with technetium-99m for SPECT/CT imaging and biodistribution studies in mice.
• In vivo MRI and SPECT/CT imaging, histological examination, and TEM analysis of tissues.

Main Results:

• Superparamagnetic iron oxide nanoparticles (SPION) were successfully integrated onto MWNTs, conferring magnetic properties.
• The hybrids exhibited high r2 relaxivities in MRI, outperforming the clinical agent Endorem®.
• Successful radio-labeling enabled quantitative SPECT/CT imaging and biodistribution analysis.
• Histological and TEM analyses confirmed in vivo stability and co-localization of SPION and MWNT in tissues without observed abnormalities.

Conclusions:

• The developed SPION-MWNT hybrids serve as effective dual MRI and SPECT contrast agents.
• These hybrid nanomaterials demonstrate significant potential for in vivo biomedical imaging applications.