Contrast agents are used in medicine to help visualize things that certain imaging modalities, such as MR or CT, cannot resolve on their own. Typically, each modality has its own imaging agents that don’t help when switching to another imaging system. To help overcome this limitation, researchers at MIT developed nanoparticles that, depending on the situation, either fluoresce or are visible under MRI.
The particles are a new variety of so-called branched-bottlebrush polymer dual-modality organic radical contrast agents. They are nitroxide radical-based nanostructures that are excitable by near-infrared light and are readily identified under MRI. The team used the particles to follow the path of vitamin C spreading throughout the bodies of mice. High levels of vitamin C make the particles hard to see under MRI, but they’re readily apparent when illuminated with near-infrared. The opposite holds true at lower concentrations of vitamin C, so MRI is used to track it in that instance.
Study in Nature Communications: Redox-responsive branched-bottlebrush polymers for in vivo MRI and fluorescence imaging…
More from MIT: Nanoparticles that enable both MRI and fluorescent imaging could monitor cancer, other diseases….