Health & Wellbeing

Mosquito inspires near-painless hypodermic needle

A Japanese scientist has created an almost painless hypodermic needle, inspired by the mosquito's proboscis
A Japanese scientist has created an almost painless hypodermic needle, inspired by the mosquito's proboscis
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A Japanese scientist has created an almost painless hypodermic needle, inspired by the mosquito's proboscis
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A Japanese scientist has created an almost painless hypodermic needle, inspired by the mosquito's proboscis
A Japanese scientist has created an almost painless hypodermic needle, inspired by the mosquito's proboscis
2/2
A Japanese scientist has created an almost painless hypodermic needle, inspired by the mosquito's proboscis

Mosquitoes are perhaps useful for something after all, besides feeding frogs. Along with his colleagues at Osaka's Kansai University, mechanical engineer Seiji Aoyagi has created an almost pain-free hypodermic needle that is based on a mosquito's proboscis. Perhaps surprisingly, the needle's patient-friendliness comes from the fact that its outer surface is jagged, not smooth.

While mosquito bites definitely do itch, the itching only occurs after the feeding is complete, due to bacteria in the anticoagulant injected by the insects. The initial "bite" itself can barely be felt. How is this possible?

A mosquito's proboscis includes an internal tubular labrum (that does the bloodsucking), which is sheathed between two serrated maxillae – one on either side. The maxillae are what first penetrate the skin and then sink into it, after which the labrum slides down between them. Because the maxillae have a jagged outer surface, they present a minimum amount of surface area to nerves in the skin. A smooth steel hypodermic needle, by contrast, makes contact with a maximum number of nerves, and is therefore uncomfortable.

Professor Aoyagi's needle, etched from silicon, mimics the labrum and maxillae. Two harpoon-like jagged-edged outer shanks first penetrate the skin, after which a smooth drug-delivering/blood-taking tube moves down between them, only touching the patient at its sharpened tip. Mosquitos vibrate their proboscis to help the maxillae ease down through the tissue, which Aoyagi has also copied – each of the three parts of his device are vibrated by tiny piezoelectric crystal motors at around 15 hertz.

The needle in its present form is tiny, at just one millimeter in length, 0.1 millimeters in diameter, and with walls a mere 1.6 micrometers thick. It is attached to a five-millimeter-wide tank, designed for storing fluids that the needle collects. To test the needle, Aoyagi's Kansai team used it to puncture silicone rubber with a skin-like resistance, underneath which was a container of red dye. The needle successfully drew the dye into its tank.

When tested on humans, the test subjects stated that it was much less painful than a traditional hypodermic, but that what discomfort there was lasted longer. Aoyagi believes that by copying more of the mosquito's seven mouthparts, including a system to steady the needle as it enters the skin, that discomfort could be further reduced in future versions.

He hopes that the needle could eventually be used to draw samples in labs, or that it could lead to the development of small wireless monitoring devices, which would be permanently attached to the bodies of people such as diabetics.

Via New Scientist

16 comments
donwine
If this lowly insect is a product of an accidental evolution - how is it that it has such a good design and one worthy of copying? Doesn\'t a design have a designer?
faceless minion
Yep. His name is C. Darwin.
windykites
Maybe you don\'t feel a mosquito bite because it is such a tiny proboscis. Compare with the diameter of a regular needle. Is it really worth going to all this effort, anyway? It is often the thought of an injection that makes it feel worse. I seem to remember that there was a device that injected without the use of a needle; just a high pressure jet. On the subject of design, how could a mosquito develop such an efficient instrument? By trial and error? I don\'t think so. How big is it\'s brain? How could it come up with the idea in the first place? Hmm. I need something to pierce the skin so that I can feed on some substance that I think will be nutritious. What shall I feed on in the meantime? Why will I need to feed on blood, if I already eat something that obviously sustains me? Just think that through for a moment.
Gene Jordan
@faceless minion: C. Darwin was a theorist. He didn\'t \"design\" anything. He only made a few observations.
rdinning
My problem is I remember reading the same announcement, nearly word for word, about 1998. I\'m still waiting for the ouch less needles.
michael_dowling
The key here is the sharpness of the needle.When I get blood drawn,I rarely feel anything more than a mosquito bite..
warren52nz
Oh no, not the old \"Evolution is wrong\" argument! Most people don\'t realize what 4 BILLION years means and in the case of insects that means billions of generations too. Natural Selection can do a LOT in a billion generations! It only takes 6 rolls of the dice to get a Yahtzee (on average).
Leong Hee Chan
Hi guys, I love this painless needle and thanks to our mosquitoes.... great research to read!
Stuart Halliday
What happened to those instruments that inject drugs painlessly via compression?
donwine
I just love the way people reason. In the face of real thought provoking questions - instead of any solid proof for evolution - suddenly a few more billion years are added. In the old days it was millions of years. A mosquito only had a few hours to developed a very handy drilling rig because he had no mouth to start with. What kept him alive until his marvelous invention was completed? How much time did he have to get it right? How did he design DNA so he could reproduce? I think his life span is only 4 months. If this insect depended on blood, then what did he do while waiting around a few billion years until a HIGHER life form came about that had blood??
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