Magnetic core-shell nanowires as MRI contrast agents for cell tracking

Area of Science:

• Materials Science
• Biomedical Engineering
• Nanotechnology

Background:

• Accurate cell localization and migration tracking are crucial for successful cell implantation therapies.
• Magnetic Resonance Imaging (MRI) offers a non-invasive method for cell monitoring when paired with contrast agents.

Purpose of the Study:

• To evaluate iron-iron oxide core-shell nanowires as contrast agents for cell tracking using MRI.
• To investigate the magnetic properties and biocompatibility of these nanowires for theranostic applications.

Main Methods:

• Synthesized and characterized iron-iron oxide core-shell nanowires.
• Assessed magnetic relaxivities (longitudinal and transverse) at 1.5 T and 7 T.
• Tested different oxidation levels and surface coatings.
• Demonstrated nanowire-labeled cell detection in vitro and in vivo using T2-weighted MRI.

Main Results:

• Core-shell nanowires exhibited high performance as T2 contrast agents with tunable transverse relaxivities.
• Successfully detected nanowire-labeled breast cancer cells in tissue phantoms and mouse brains.
• Achieved high-resolution cell detection (down to ~10 cells in vivo) over 40 days with minimal labeling concentration (0.8 μg Fe/mL).

Conclusions:

• Iron-iron oxide core-shell nanowires are efficient T2 contrast agents for longitudinal cell detection via MRI.
• These nanowires offer a promising theranostic platform for cell therapy, with potential for magnetic guidance and photothermal response.