In order to detect the presence of nearby females, the male silk moth utilizes an oily coating on his antennae. Any female pheromone molecules that are in the air will stick to that coating, which then guides them through nanotunnels in the insect's exoskeleton, and ultimately to nerve cells that alert Mr. Moth to the fact that there are ladies in the area. It's a clever enough system that scientists from the University of Michigan have copied it, in hopes of better understanding neurodegenerative diseases such as Alzheimer's.
Michael Mayer, an associate professor in U Michigan's departments of Biomedical Engineering and Chemical Engineering, is interested in proteins known as amyloid-beta peptides. It is thought that when they coagulate into fibers, they can adversely affect the brain.
In order to study the size and shape of these fibers, Mayer and his team created a "fluid lipid bilayer," their own version of the moth's oily substance. Instead of going on a bug's antennae, however, the bilayer is applied to a silicon chip that has a microscopic nanopore drilled through it. That chip is placed between two chambers of salt water, one of which then has peptides added to it. An electrical current is subsequently applied to the nanopore. Peptide molecules bond with the oily coating and are guided through the nanopore, altering its electrical resistance in the process. By analyzing these changes, observers can determine things such as the size, electrical charge and shape of the molecules.
"Existing techniques don't allow you to monitor the process very well. We wanted to see the clumping of these peptides using nanopores, but every time we tried it, the pores clogged up," Mayer said. "Then we made this coating, and now our idea works ... This could help us possibly diagnose and understand what is going wrong in a category of neurodegenerative disease that includes Parkinson's, Huntington's and Alzheimer's."
The research was recently published in the journal Nature Nanotechnology.
This isn't the first time that scientists have looked to moths and their kin for bright ideas. German researchers recently created an antireflective coating for solar panels that work on the same principles as moth eyes, while butterfly wings were the inspiration behind anticounterfeiting technology developed last year in the UK.