world’s most dangerous Animals are picky eaters. Because they transmit viral diseases like Zika and chikungunya, and the parasites that cause malaria, mosquitoes love to suck blood. Aedes aegypti responsible for more than 700,000 won deaths worldwide every year.
But in Omid Veiseh’s lab at Rice University, his team of bioengineers are struggling to catch mosquitoes. Typically, researchers who study mosquito feeding by letting them bite live animals—lab rats, or graduate students and postdoctoral fellows dedicate themselves to science. That’s not ideal, because laboratory animals can be expensive and impractical to work with, and their use can raise ethical issues. Student’s arms do not extend well for large tests.
Working with entomologists from Tulane University, the Rice team wanted to develop a way to study mosquito behavior without the difficulty of testing large numbers of animals. Their solution was something entirely different: real blood encased in lifeless hydrogels. Veiseh said: “It feels like jelly. “The mosquitoes have to bite through the jelly to suck blood.”
At least, in theory. Sometimes insects won’t bite. Sometimes they can’t get through their straw-like proboscis. In the end, the team made enough tweaks—such as changing the hardness of the gel—and it happened. “It was a big eureka moment for us,” Veiseh said. “We saw this mosquito crawling on the gel, biting it and sucking blood.”
Write today in magazine Frontiers in Bioengineering and Biotechnology, The team describes their scalable platform for testing mosquito behavior. Their 3D printed hydrogel simulates skin and contains zigzag channels through which real blood can be pumped. To test the gels, the researchers pointed a camera at them and used a computer vision algorithm to quickly analyze how many mosquitoes head to the buffet. In a proof-of-concept experiment, they showed that mosquitoes refused to eat when the hydrogel smelled of repellent.
Dawn Wesson, a medical entomologist from Tulane, who co-led the work, says the gels could be used to design a community alert system — an attraction and observation platform. mosquitoes in an area before the disease they spread gets out of control. “If you’re trying to detect infection in wild mosquitoes, hundreds of these in the field — in some sort of surveillance system — can be helpful,” she says.
The team also suggests that this could become a low-cost system for inventing and testing repellents. “The good thing about it is it’s trying to mimic human skin without using real people,” said Perran Ross, a medical entomologist at the University of Melbourne, Australia, who was not involved in the work. “This will be quite helpful to find mosquito repellent. And that’s a really good way to do it if using real people isn’t feasible.”
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Inventing a new type of mosquito repellent is really a big deal, given the devastating health effects of these insects. While repellents work well today, they’re far from perfect — and comfort is arguably as important as potency if you really want people to adopt disease prevention methods. DEET is the gold standard, but it doesn’t last long, is smelly, and can be harsh on sensitive skin. “There have not been large-scale efforts to really come up with alternatives or better solutions,” says Veiseh.
