Diagnosing Alzheimer’s Disease in the early stages is tricky — there’s really no test or imaging to distinguish AD from plain old forgetfulness or dementia (an expensive new PET scan is in the works). But now MIT scientists have a promising injectable dye that could light up amyloid plaques characteristic of the disease:
Swager, who is head of the chemistry department, and colleagues developed the new dye, called NIAD-4, through a targeted design process based on a set of specific requirements, including the ability to enter the brain rapidly upon injection, bind to amyloid plaques, absorb and fluoresce radiation in the right spectral range, and provide sharp contrast between the plaques and the surrounding tissue. The compound provided clear visual images of amyloid brain plaques in living mice with specially prepared cranial windows.
To make the technique truly noninvasive, scientists must further refine the dye so it fluoresces at a slightly longer wavelength, closer to the infrared region. Light in the near-IR range can penetrate living tissue well enough to make brain structures visible. Swager likens the effect to the translucence produced when one holds a red laser pointer against the side of a finger.