Author Lina Zeldovich Illustration James Provost
You could call mosquitoes the scourge of the earth: They transmit some of the nastiest diseases known to man, including malaria, which kills hundreds of thousands of people a year. To protect themselves in at-risk areas, travelers and locals alike coat themselves in toxic DEET-based sprays, or take pills and shots that can have side effects. Anandasankar Ray, an entomology professor at UC Riverside, worked with an innovation company called ieCrowd to develop a better way. Mosquitoes normally sniff us out by detecting the plumes of carbon dioxide we exhale; Ray learned that some natural smells can shut down the bugs’ carbon dioxide receptors, effectively rendering humans invisible to the pests. So to keep potential targets (that would be you and me) surrounded at all times by an invisibility cloak so effective it would make Harry Potter jealous, they developed colorful stickers called Kite Patches that stick to T-shirts. Here’s how they did it.
1. In his research, Ray noticed that mosquitoes dislike diacetyl—a byproduct of yeast fermentation that’s present in beer and wine. When airborne, diacetyl can block the bugs’ carbon dioxide detectors. Unfortunately, it smells like rancid butter, so Ray combed through thousands of FDA-approved food additives and odorants to find compounds that worked the same way but didn’t stink.
2. To test the compounds, Ray used a micro-scope to place tiny electrodes in the carbon dioxide receptors in mosquitoes’ “noses.” Then he exposed them to the test smells. The electrical signals, which are similar to those in electrocardiograms, showed that the smells incapacitated the receptors. Ray sent his findings to ieCrowd, which would figure out how to add the compounds to stickers.
3. Next, ieCrowd tested the stickers in chambers the size of small buildings—big enough to accommodate mock huts where patch-wearers sat surrounded by hundreds of pests. The tests worked: When the mosquitoes approached people wearing patches, they became confused and zipped away. Now, ieCrowd is preparing to test the patches in Uganda, where malaria is a major problem.