“Right now, AD is diagnosed by clinical interviews and the diagnosis accuracy is less than 90%.”

Our paper is about Alzheimer’s disease (AD), and there's tremendous interest in this subject. The story in our paper is very novel and very significant, which is why both the National Science Foundation and the Proceedings of the National Academy of Sciences promoted it—and why the media coverage was high. We offer hope of a lab test for AD—there’s none currently available—but, with continued effort, our work potentially could rectify that.

Both. Our findings establish that spinal fluid (CSF) contains "ADDLs" (amyloid-derived diffusible ligands), which are a new type of neurotoxin that we previously discovered and found in brain tissue affected by Alzheimer’s. It seems increasingly likely that ADDLs, cause AD memory loss. The new findings show that ADDLs in CSF show a striking AD-dependence. This suggests that ADDLs might provide, for the first time, a real biomarker for the disease.

The methology is incredible! Our measurements depended entirely on a novel nanotechnology invented in Chad Mirkin’s laboratory. His "Biobarcode™" is orders of magnitude more sensitive than the best ELISAs (Enzyme linked immunosorbent assays) and it retains the specificity of immunassays. It can be adapted to other diseases and applications and is a real breakthrough. NSF has been a real force in helping to develop this technology through its support of Northwestern’s Nanoscale Science and Engineering Center.

The conclusions are exciting because they lay the foundation for lab tests that could provide a definitive diagnosis for AD. Right now, AD is diagnosed by clinical interviews and the diagnosis accuracy is less than 90%.

We discovered ADDLs a number of years ago in biochemical experiments. When we found that ADDLs could inhibit memory mechanisms experimentally, it became crucial to determine whether they actually occurred in AD brain tissue. Assessment of CSF was part of the effort. However, prior to the Biobarcode™, we couldn't measure levels of CSF-ADDLs.

Given our aging population and the incredible financial burden of AD, it’s going to be important to find an effective AD treatment. As of now, none exists. We're hopeful that our findings and methods will accelerate drug discovery by providing reliable assessments of the disease, in addition to validating our concepts concerning disease mechanisms.