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Are those who feel weak in the knees when seeing the needle during blood drawing blessed?

Inspired by leeches, Swiss researchers released a new blood collection device a few months ago.The device does away with the needles that many people fear, and instead uses a combination of suction cups and microneedles to obtain enough blood with minimal trauma.

Leeches have a suction cup in their mouths and many sharp "small teeth" in their mouths. They create negative pressure when swallowing to suck blood. The new blood collection device developed by the Swiss Federal Institute of Technology in Zurich also works on a similar principle.It is first attached to the person's upper arm through a suction cup. After pressing, the microneedles inside the device will pierce the skin, and then the blood can be collected through negative pressure.

When it comes to leeches, many people may feel scared or disgusted by them, butThe scientific community has been working hard to study the potential therapeutic value of leeches, some of which have been actively applied.

Hungry blood-sucking leeches are very sensitive to changes in their surroundings, such as light and vibrations. When encountering a target host, some leeches in aquatic environments will even "chase" the target animal.They have a sucker on their head and tail, the mouth sucker is small and the tail sucker is large.When running, the leech's body will constantly "stretch and contract" like a caterpillar and crawl forward, with the front and back suckers moving alternately until the front sucker touches the host and successfully sucks it.

But don't worry,Land leeches encountered by people on foot generally do not chase their prey; they often attach themselves to their hosts accidentally.Once the leech has secured itself with its suction cups, the three jaws in the Y-shape of its mouth go to work. Each jaw is like a serrated knife, with rows of tiny teeth that move back and forth, cutting through the host's skin.

Under normal circumstances, when we are injured and bleed, the body will spontaneously start some physiological mechanisms to stop bleeding: platelets will gather at the damaged part of the blood vessel and then produce a large amount of blood.Thrombin, a blood clot will form at the wound to further stop the bleeding.

However, leeches have a solution. They release a substance calledHirudin（hirudin）The enzymeDirectly inhibit the activity of host thrombin, thereby preventing the formation of blood clots in the host's wounds, and the blood in the wounds can keep flowing, leeches can continue to suck blood. The time they suck blood varies from tens of minutes to several hours.

Some blood-sucking leeches have three jaws in their mouths, which are lined with many small teeth. In the wild, if you find a leech on your body and want to get rid of it, you can use your fingernails to push off the suckers at the head and tail of the leech to make it fall off. Image source: American Museum of Natural History

When leeches are swallowed, they create negative pressure, which draws blood into the digestive tract.A well-fed leech can swell to five times its previous body weight, and can sometimes suck up to 10 times its body weight in blood."If the blood coagulates inside the leech, it will fall to the bottom like a brick," said Kvist Currie, senior curator of entomology at the Royal Ontario Museum in Canada. (Kvist Currie) Said.

Hirudin is a powerful anticoagulant. When the leech is full and leaves, the hirudin will still work at the bite site, and the host's wound will continue to bleed for a while. And after the leech is full and leaves, the host's blood in its digestive tract may not coagulate for a long time. Previously, researchers have found thatSome leeches can live for a year after feeding on your blood once!

In English, the word "leech" is also used to describe people who always take and are unwilling to give. But in fact,Not all leeches suck blood, many species are predators, they mainly feed on small invertebrates such as snails, slugs, earthworms, etc. At the same time, in the food chain, leeches are also food for fish, turtles, waterfowl and other animals.

In the scientific research community, leeches are the darlings of many researchers. Some researchers even let leeches suck their blood in the laboratory. By studying hirudin, scientists are developingDrugs to treat blood clots and prevent strokes with fewer side effectsLeeches can also be used during surgical procedures, such asWhen a human amputated finger is reattached, the leeches can suck blood and allow fresh oxygenated blood to re-enter the severed finger.

Now, a blood collection device developed based on leeches is expected to help people draw blood more easily. In a study published in March this year by the Swiss Federal Institute of Technology,The suction cup and microneedles of the new blood collection device imitate the suction cup and small teeth in the mouth of leeches.The suction cup is fixed on the patient's arm, and when pressed, the microneedles inside the cup will puncture the skin. Then, the release of pressure in the cup will generate negative pressure, which will suck the blood and store it in a storage space containing anticoagulant.

Microneedling is less invasive and causes less pain and discomfort, the wound is easier to heal. In addition, because the microneedle is fixed inside the suction cup, it is easier to use than the traditional blood collection needle.Reduces the risk of injury to people during the puncture process and subsequent treatmentThe researchers are also developing a version of the device made from fully biodegradable materials.

Non-medical professionals can also use this blood collection device.And it can collect more blood than finger stick blood collection., improving the accuracy of diagnosis. In addition, it can be manufactured at a lower cost and is easy to carry, soVery suitable for low- and middle-income areas, which is expected to help people better fightmalariaAnd other diseases.

Malaria is currently diagnosed by taking blood from the patient's earlobe or fingertip and testing it for the presence of Plasmodium. When a mosquito infected with Plasmodium bites a healthy person, the mosquito injects the Plasmodium in its saliva into the body. The Plasmodium then enters the bloodstream. The parasites first invade the liver, where they grow and multiply in liver cells; once mature, they leave the liver and infect red blood cells in the blood.

Malaria can cause fever, chills, headache, and vomiting, which can be life-threatening in severe cases.Blood smearBy identifying the Plasmodium parasites in the body, healthcare professionals can diagnose and monitor malaria infection in their patients.

Children at higher risk of severe malaria infectionAccording to the World Health Organization, children under the age of 5 account for approximately 78% of all malaria deaths in Africa.

But at the same time,Needle phobiaThe proportion of people who have a fear of needles is not low, and children are particularly afraid of needles.About a quarter of adults and up to two-thirds of children have an intense fear of needles.Generally speaking, people's fear of needles will gradually weaken or disappear as they get older.

If you are also afraid of blood collection needles, you might as well look forward to "Leech blood collection device”。