A mosquito biting human flesh

Aside from ruining all your family picnics and camping trips, mosquitoes have also been known to transmit deadly diseases. In many countries around the world including the US, they’ve previously caused outbreaks of West Nile virus, malaria, and yellow fever. Repelling the vicious insects has stymied scientists for eons now, but a new material called graphene might just be the thing we’ve all been waiting for.

What is Graphene?

Hand holds a graphene strip

Graphene, the building block of graphite (most famously used for making pencil tips), is believed to be one of the thinnest materials on Earth at just one atom deep. It’s also around 200 times tougher than steel and a superb conductor of electricity and heat. For these reasons alone, it’s proven a very hot commodity, and it’s constantly being tested for several different applications. So far, it’s been researched in regards to improving solar cells, DNA sequencing, computer chips, batteries, and even tennis rackets.

How It Repels Mosquitoes

Brown University researchers recently coated a thin section of fabric called GO cloth with graphene and discovered that the mosquito proboscis — the sharp spiky part of their mouth that penetrates skin — was unable to penetrate it. Even more exhilarating, they found that graphene totally obstructed the chemicals on skin that attracted the pests in the first place. PhD student Cintia Castilho, the study’s lead author, notes: “With the graphene, the mosquitoes weren’t even landing on the skin patch — they just didn’t seem to care.”

Unfortunately, the mosquitoes were only unable to penetrate the fabric when dry. When it was wet, they easily broke through to the skin. However, a customized version of the cloth with a low oxygen content called rGO worked to repel the mosquitoes whether it was dry or wet. The problem here is that rGO is not breathable, which makes it unsuitable to use on human skin. For that reason, the main challenge remains modifying the standard GO cloth so that it’s stronger and equally effective when wet or dry.

The Experiment

Mosquitoes rest on sections of the GO cloth free of graphene.

Real people were used to test the graphene cloth. Each of them had a small patch of skin on their arms covered with the stuff before exposing the area to several mosquitoes at once. That area of skin included three sections: one bare, one covered with cheesecloth, and one covered with a thin layer of GO. All the mosquitoes involved were lab-raised, so they were guaranteed free of disease.

This research proved that the GO worked, with that area being the only one of the three that wasn’t eagerly attacked by the insects. “We had assumed that graphene would be a physical barrier to biting through puncture resistance, but when we saw these experiments, we started to think that it was also a chemical barrier that prevents mosquitoes from sensing that someone is there,” Castilho adds.

A mosquito biting human flesh

To confirm the chemical barrier theory, the researchers applied a small amount of human sweat to the exposed side of a GO cloth. When placed here, the mosquitoes congregated on the patch very similar to how they went after bare skin.

The Brown University team says they will continue with their studies in hopes of finding appropriately engineered graphene linings, which in turn could be used to produce clothing that puts an end to bothersome and often deadly mosquito bites.