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Updated: Jul 19, 2026
11:27
Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging
Published on: December 4, 2016
Calcium-sensitive MRI contrast agents based on superparamagnetic iron oxide nanoparticles and calmodulin
Tatjana Atanasijevic1, Maxim Shusteff, Peter Fam
1Department of Nuclear Science and Engineering, and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 150 Albany Street, NW14-2213, Cambridge, MA 02139, USA.
Summary
Researchers developed novel calcium indicators for magnetic resonance imaging (MRI) by linking iron oxide nanoparticles with calmodulin. These sensors enable sensitive detection of calcium changes for molecular imaging in biological systems.
Area of Science:
- Biomedical Engineering
- Molecular Imaging
- Nanotechnology
Background:
- Magnetic resonance imaging (MRI) is a powerful tool for non-invasive imaging.
- Developing sensitive and specific contrast agents for MRI remains a challenge.
- Calcium ions (Ca2+) play crucial roles in cellular signaling, and their dynamic changes are important to monitor.
Purpose of the Study:
- To create a new class of calcium indicators for MRI.
- To leverage iron oxide nanoparticles and calmodulin for sensitive calcium detection.
- To enable functional molecular imaging of biological signaling networks.
Main Methods:
- Conjugation of iron oxide nanoparticles with calmodulin and its targets.
- Utilizing calcium-dependent protein-protein interactions to induce nanoparticle clustering.
- Measuring changes in T2 relaxivity as an indicator of calcium concentration.
- Engineering sensor variants with tunable response characteristics.
Main Results:
- Developed a family of calcium indicators with up to 5-fold changes in T2 relaxivity.
- Achieved detection of calcium concentration changes near 1 microM Ca(2+).
- Demonstrated robust MRI signal changes at low nanomolar particle concentrations.
- Showed that sensor response can be tuned by protein mutation.
Conclusions:
- The developed calcium indicators offer a potent and sensitive method for MRI-based calcium sensing.
- These sensors are suitable for detecting elevated intracellular calcium levels.
- The technology holds promise for functional molecular imaging of cellular signaling in live specimens.
- Further development with cellular delivery systems could enhance in vivo applications.
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