How a mosquito will bite
Mosquitoes will serve as a prototype for a painless needle
Alexey Yevglevsky, Naked Science
Scientists from the Ohio State University have studied in detail the proboscis of mosquitoes to imagine what a needle would look like, painlessly entering under human skin. The results are published in the Journal of the Mechanical Behavior of Biomedical Materials (Gurera et al., Lessons from mosquitoes’ painful piercing).
The object of the study was female mosquitoes Aedes vexans. The engineers examined the part of the proboscis called the upper lip. With its help, insects suck blood. To determine its characteristics, scientists used the nanoindentation method, during which an indenter (an element of a hardness measuring device) is pressed into the prototype. They found that the upper lip is softest at the tip and at the edges, but becomes harder higher up the trunk. According to experts, this is an important feature, since soft tissue causes less pain during piercing.
After analyzing existing studies on mosquitoes, scientists have identified three more factors contributing to the painless penetration of the proboscis. The first is its saw-like shape. With the help of tiny notches, the trunk penetrates under the skin more easily. The second is the pressing force. It is three times lower than the lowest force when piercing with an artificial needle. According to the researchers, this is possible due to the sawtooth shape. The last component is an analgesic. As soon as the mosquito inserts the proboscis, it releases saliva under the skin with proteins blocking the peptide bradykinin, which provides pain sensitivity.
A drawing from the Ohio State University press release Looking to mosquitoes for a way to develop painless microneedles - VM.
Combining all four features, the researchers presented a vision of the needle of the future. In their opinion, it consists of two parts: the first one simultaneously injects painkillers with penetration, and the second one takes blood or injects the drug. The last needle has a sawtooth shape and has a soft tip for easy insertion. The engineers claim that the materials needed for the prototype already exist, it remains only to receive financial support.
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