|Chemical map of an aggregate of the Alzheimer’s disease peptide amyloid-beta (blue), and accumulated iron (red), obtained using the synchrotron x-ray technique known as spectromicroscoppy|
Combining these properties enables us to perform both microscopy (creating nanoscale images of our samples) and spectroscopy (measuring a property of our sample as the x-ray wavelength is scanned). In fact, the latest state-of-the-art instruments enable us to combine these techniques into a process known as spectromicroscopy. Here we obtain a set of nanoscale images at many different x-ray wavelengths. This enables us to measure the distribution of the chemical and magnetic properties of our sample across regions as small as a few nanometers. It is therefore possible to study how different materials interact at the length scales of relevance to biology.
Alzheimer's disease is a major condition effecting increasingly large numbers of people, both old and young. The importance of this work is that it demonstrates a potential mechanism for the damage that occurs in the brain during Alzheimer’s disease. Using the same x-ray techniques we have now begun to study specimens of human brain tissue donated by Alzheimer’s patients, and can see interesting parallels in the nature of iron in these tissue samples compared to those we obtain in the lab. Understanding the role of iron in diseases such as Alzheimer’s is important for both early diagnosis using MRI scans, and for potential new treatments that could use the accumulated iron as a chemical target for drugs to attack.