The deadliest in the world the animal is picky eater. Because they carry viral diseases such as Zika and chikungunya, as well as parasites that cause malaria, mosquitoes love blood-sucking Aedes aegypti are responsible for over 700,000 deaths worldwide every year.
But in Omid Veiseh’s lab at Rice University, his team of bioengineers struggled to get mosquitoes to eat. Typically, researchers study the diet of mosquitoes by allowing them to bite live animals — lab mice or graduate students and postdocs who offer their powers to science. This is not ideal because lab animals can be expensive and impractical to work with, and their use can raise ethical issues. Student hands do not scale well for large tests.
In collaboration with entomologists at Tulane University, Rice’s team wanted to develop a way to study mosquito behavior without the hassle of experimenting with large numbers of animals. Their solution was completely different: real blood encapsulated in a lifeless hydrogel. “Looks like jelly,” Veiseh says. “Mosquitoes have to bite through the jelly to get to the blood.”
At least theoretically. Sometimes the insects didn’t bite. Sometimes they could not push through their straw-like proboscis. Finally, the team made enough changes, such as changing the hardness of the gel, and it happened. “It was a big revelation for us,” Weise says. “We saw this mosquito crawling on the gel, biting it and sucking blood.”
I am writing today Magazine The frontiers of bioengineering and biotechnology, the team describes its scalable mosquito behavior testing platform. Their 3D-printed hydrogels mimic skin and contain zigzag channels through which real blood can be pumped. To test the gels, the researchers pointed cameras at them and used a computer vision algorithm to quickly analyze how many mosquitoes dived mouth first into the buffet. In a proof-of-concept experiment, they showed that mosquitoes refuse to eat when hydrogels smell like repellent.
Dawn Wesson, a Tulane medical entomologist who led the work, says the gels could be used to develop a community alert system, a platform that attracts and watches for mosquitoes in an area before the disease they spread gets out of hand. “If you’re trying to detect infection in wild mosquitoes, hundreds of these things in the field – in some kind of observational array – could be useful,” she says.
The team also believes it could be a low-cost system for inventing and testing repellents. “The good thing is that it tries to mimic human skin without using a real person,” says Perran Ross, a medical entomologist at the University of Melbourne, Australia, who was not involved in the work. “It would be quite useful for finding mosquito repellants. And that’s a really good way to do it if you can’t use a real person.”
The invention of a new mosquito repellent is actually a big deal, given the damage that these insects cause to health. While modern repellents work well, they are not perfect, and comfort is perhaps as important as effectiveness if you really want people to practice disease prevention practices. DEET is the gold standard, but it doesn’t stay active for very long, it’s smelly and rough on sensitive skin. “There hasn’t been a massive effort to really come up with alternatives or better solutions,” Weizeh says.