NIEHS-Funded Research Finds that Graphene Shield Shows Promise in Blocking Mosquito Bites

On August 26, 2019, the National Institute of Environmental Health Sciences (NIEHS) announced that the results of an NIEHS-funded study show that graphene could provide alternatives to chemicals in insect repellant and protective clothing.  The study, “Mosquito Bite Prevention through Graphene Barrier Layers,” was published in the Proceedings of the National Academy of Sciences.  According to the abstract, the researchers hypothesized that graphene films may provide mosquito bite protection for light, fiber-based fabrics.  The researchers investigated the fundamental interactions between graphene-based films and the mosquito species Aedes aegypti through a combination of live mosquito experiments, needle penetration force measurements, and mathematical modeling of mechanical puncture phenomena.  The abstract states that “the results show that graphene or graphene oxide nanosheet films in the dry state are highly effective at suppressing mosquito biting behavior on live human skin.  Surprisingly, behavioral assays indicate that the primary mechanism is not mechanical puncture resistance, but rather interference with host chemosensing.”  The researchers propose that the interference is “a molecular barrier effect that prevents Aedes from detecting skin-associated molecular attractants trapped beneath the graphene films and thus prevents the initiation of biting behavior.”  According to the abstract, placing water or human sweat on the external film surface circumvents the molecular barrier effect.  In this scenario, the abstract states, “pristine graphene films continue to protect through puncture resistance — a mechanical barrier effect — while graphene oxide films absorb the water and convert to mechanically soft hydrogels that become nonprotective.”