'5-D protein fingerprinting' may provide hope for Alzheimer's

Scientists have engineered a new technique for precisely measuring the properties of individual protein molecules floating in a liquid, a finding that could one day lead to advances against neurodegenerative diseases like Alzheimer's and Parkinson's.

The new technique called a "five-dimensional (5-D) fingerprint" can measure an individual molecule's shape, volume, electrical charge, rotation speed and propensity for binding to other molecules.

It can also provide additional descriptors like gender, hair colour and clothing, making it much easier to identify specific proteins.

"Identifying individual proteins could help doctors keep better tabs on the status of a patient's disease and could also help researchers gain a better understanding of exactly how amyloid proteins are involved with neurodegenerative diseases," said Michael Mayer, Professor at University of Fribourg in Switzerland.

Measuring properties of proteins in blood and other body fluids could unlock valuable information, as the molecules are a vital building block in the body. 

But, sometimes proteins known as amyloid proteins do not form properly. They clump together to block normal cell function and cause brain cell degeneration and disease.

Current methods to identify these proteins are expensive, time-consuming and difficult to interpret and can only provide a broad picture of the overall level of amyloids in a patient's system.

"Amyloid molecules not only vary widely in size, but they tend to clump together into masses that are even more difficult to study. Because it can analyse each particle one by one, this new method gives us a much better window to how amyloids behave inside the body," Mayer said.

For the research, the team used a nanopore 10-30 nanometers wide -- so small that only one protein molecule can fit through at a time. They then filled the nanopore with a salt solution and passed an electric current through the solution.

As a protein molecule tumbles through the nanopore, its movement causes tiny, measurable fluctuations in the electric current. Carefully measuring this current can help determine the protein's unique 5-D signature and identify it almost instantly, the researchers said.

The findings are published in the journal Nature Nanotechnology.