Credit: Alan Jasanoff, McGovern Institute for Brain Research at MIT
Sensing Calcium in Neurons Sensing calcium as it flows into neurons following firing can potentially track information flow throughout the brain's circuitry, and at the McGovern Institute at MIT, Alan Jasanoff has developed a calcium contrast agent for non-invasive MRI detection. At top, a schematic shows how superparamagnetic nanoparticles coated with two proteins (red and green) form mixed aggregates due to calcium-dependent protein-protein interactions. The middle panel shows atomic force micrographs of actual sensor particles in the absence (left) or presence (right) of calcium. The bottom panel shows progressive brightening of MRI images (green to red pseudocolor) as the calcium concentration is increased from zero (left) to 5 micromolar (right).