How Strong Are Mosquito Needles?
WouterCurrently, most people are worried about mosquitoes, which are able to transmit diseases such as West Nile virus and dengue fever. But what makes the insects so dangerous? Scientists have been studying the anatomy of a mosquito bite for decades. They’ve discovered that a female mosquito uses a labrum, a flexible, lip-like sheath, to pierce the skin.
The labrum’s curved shape works like a straw to funnel blood. When the fascicle enters the skin, it retracts short distances in both directions. It also reacts to chemical signals from the blood. This allows it to spread out the blood vessel cells.
In addition to the tubular labrum, the mosquito mouth has six needle-like parts called stylets. These harpoon-shape notches, which anchor soft tissue, are located at the tip. These notches reduce friction and allow the needle to be sharper.
Professor Aoyagi developed a needle that mimics the labrum. The new microneedle has an external diameter of 60 microns, about the same size as the mosquito’s mouthpart, and an internal diameter of 25 microns. Its shaft is made of stronger titanium, which reduces the risk of snapping. The serrated tube moves at a rate of less than 0.1 mm, which is much smaller than the speed of sound.
The harpoon-shape notches also anchor surrounding soft tissue, reducing deformation and friction. This insertion system is more efficient and less painful. In addition, the incremental motion of the needle and cannula produces vibratory insertion, which helps reduce displacement of the organ during insertion.
