Needles – none of us like them. But whether they're a painful inconvenience, or an outright trauma, jabs are something we all have to endure at one time or another. Researchers from Ohio State University think it doesn't have to be this way. They're drawing inspiration from the mosquito – and in particular how it's able to puncture human skin without causing pain with its needle-like proboscis – to make injections a less miserable experience.
By studying existing scientific research, the team found three ways that mosquitoes avoid inflicting pain when drawing blood. They secrete saliva which includes a protein which numbs feeling. The fascicle, or part that draws blood, vibrates when piercing the skin, which reduces the force needed. And its serrated, which also, counterintuitively, makes penetration easier. (And in fact, needles which mimic this serration have been developed before.)
But by examining the proboscises of mosquitoes for themselves, the researchers found a fourth method. Female Aedes vexan, which are the most common mosquito in North America, have a proboscis which varies in stiffness. The labrum, which is the outer cover of the proboscis, gets softer nearer the tip, which, yet again, reduces the force needed to pierce the skin.
"This is important because a softer and more compliant tip may cause less pain when it pierces the skin because it deforms the skin less," Ohio State's Bharat Bhushan says in a press release.
These powers combined, mosquitoes need only apply one third of the force needed for an artificial needle to pierce the skin – and this is without the influence of the numbing agent factored in.
Bhushan thinks all of these tricks could be combined in an artificial micro-needle which would, in fact, combine two needles. One would immediately inject a numbing agent (presumably other than mosquito saliva) while the other would be used to either draw blood or inject the necessary drug.
Because of the greater expense of the needle, it's unlikely this would be used in all cases, but may be a good candidate for young children or people who have a fear of needles or jabs.
"We have the materials and knowledge to create a micro-needle like this," Bhushan concludes. "The next step is to find the funding support to create and test such a device."
While in the economic West, mosquitoes are little worse than a nuisance, their effect is devastating elsewhere. Half of the world's population is thought to be at risk from malaria, which is caused by parasites spread by mosquito bites. The disease caused an estimated 429,000 deaths in 2015.
A painless mosquito-inspired needle may pale into insignificance alongside these numbers, but it makes a nice change for mosquitoes to be associated with a positive health story for once, even if this remains theory for now.
The research has been published in in the Journal of the Mechanical Behavior of Biomedical Materials.
You can see a summary of the research in the video below.
Sources: Ohio State University
