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Mosquito inspires near-painless hypodermic needle

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April 4, 2011

A Japanese scientist has created an almost painless hypodermic needle, inspired by the mos...

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

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
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16 Comments

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?

donwine
5th April, 2011 @ 07:51 am PDT

Yep. His name is C. Darwin.

faceless minion
5th April, 2011 @ 09:53 am PDT

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.

windykites1
5th April, 2011 @ 10:37 am PDT

@faceless minion: C. Darwin was a theorist. He didn't "design" anything. He only made a few observations.

Gene Jordan
5th April, 2011 @ 12:46 pm PDT

My problem is I remember reading the same announcement, nearly word for word, about 1998. I'm still waiting for the ouch less needles.

rdinning
5th April, 2011 @ 02:15 pm PDT

The key here is the sharpness of the needle.When I get blood drawn,I rarely feel anything more than a mosquito bite..

michael_dowling
5th April, 2011 @ 03:20 pm PDT

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).

warren52nz
5th April, 2011 @ 04:17 pm PDT

Hi guys,

I love this painless needle and thanks to our mosquitoes.... great research to read!

Leong Hee Chan
5th April, 2011 @ 08:13 pm PDT

What happened to those instruments that inject drugs painlessly via compression?

Stuart Halliday
6th April, 2011 @ 01:05 am PDT

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??

donwine
6th April, 2011 @ 10:36 am PDT

evolution is a fact, while no one should expect you to completely understand all the evidence, you should atleast look up some before stating worthless arguments.

or at the very least look up the facts regarding your reasons for not believing and see if they are valid reasons.

Jacob Shepley
7th April, 2011 @ 11:54 pm PDT

Being myself an evolutionary biologist, here is too little space here to explain current knowledge completely. (read population genetics, or

But let's just say we have advanced a lot since Darwin, in these 150 years!

Evolution is defined as just change, not by design, not by usage of parts. Selection deletes many useless aberrants. But many others are still kept, and these aberrants are preaptations to new functions. The mosquito proboscis is just a deformed set of mouthpieces found in all arthropods.

There is an equilibrium between selection, mutation, genetic drift, hibridation between different populations, and the list goes on...

Since all species are postulated to come from one original ancestor species, all current animals have the same "age". Some have become simpler, others more complex, but all have adapted to their niche. Mosquitoes have evolved what in ecology is called an "r" strategy (look it up): it swarms the land with very simple, small individuals. Are they any less adapted than us? NO. We can't beat them. We can just keep them at bay. Just like ants. We have the opposite strategy: "K". We grow bigger, have few siblings, and invest a lot of energy in parental care.

Again, what we see now is the product of selection, mutation, genetic drift... what is left we divide it in categories (species, ecological strategies), but these are the product of our thought. The Nature simply is. Period.

cachurro
8th April, 2011 @ 07:20 am PDT

Here is a fact. If a person is facing trial for their life on a 40 year old cold case and you try to convict only on radio carbon dating as your evidence - it wouldn't even get to trial. And I'm expected to believe in theories about billions of years when man only lives an average of 70 to 80 years? The more numbers piled on only makes it seem more ridicules. It is a religion based on blind credulity and no facts. The smart inventors like this man learn from the intelligent designs in the natural world created by design. Where would we be today without these marvels? With all of the years of mans experience - to this day he can not name one food that he has created. Whether we like it or not - think about your next meal and ask yourself what you would have done if your creator had not prepared it for you. Is the evolution theory the thanks we give him?

donwine
8th April, 2011 @ 07:41 am PDT

Cachurro, thank you for taking the time. I hadn't realized the complexity of the 'big picture' of evolution, the equilibrium you mention, so you've added much to my understanding of the process with just a few well-chosen words. I appreciate it.

Jeff Chernoff
8th April, 2011 @ 09:40 pm PDT

Yes... we have come a long way since Darwin, but the Darwinists still survive and the Creationists continue to believe! The fact of the matter is... that the ToE has long since given up on the "origin of the species" and have settled for something like... evolution is whatever it needs to be... as we attempt to determine what it is!

By the way...

...I am blue-eyed and I'm thinking about planting a banana in the back yard and while I am waiting for my banana tree to grow, I will contemplate what this has to do with a mosquitoes nose!

MAGForce
12th April, 2011 @ 01:48 pm PDT

"Here is a fact. If a person is facing trial for their life on a 40 year old cold case and you try to convict only on radio carbon dating as your evidence - it wouldn't even get to trial."

I'd be happy to learn what kind of hypothetical case are you implying, as for now it sounds ridiculous. :D

Renārs Grebežs
9th May, 2011 @ 01:52 am PDT
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