Probes Shed New Light on Alzheimer's Cause

A study by Rice University researchers in the Journal of the American Chemical Society described a technique to monitor the formation of soluble amyloid beta peptide aggregates that are believed to play a role in the onset of Alzheimer's, reports Phys.org . The team developed a ruthenium-based fluorescent complex that binds to these peptides, and labels the resulting oligomers. This will enable scientists to easily track the progress and movements of aggregates as they expand. "There's a view in the field that soluble oligomers are the main cause of neuronal degeneration, because these oligomers are toxic to neurons," said Rice Professor Angel Martí. "These oligomers are definitely associated with Alzheimer's pathology, so there's been a need for tools to help us study them." The ruthenium complexes exploit fluorescence anisotropy, in which the fluorescent response is polarized, glowing brighter in some directions than others. "When the . . . probe binds to a big macromolecule, it rotates more slowly," Martí explained. "That's how we know we have oligomers, and then we can track their growth and propagation."