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Full Version: The Injections That Do Not Require a Needle
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Pain during vaccination and fear of needles could completely disappear in the near future, writes MIT news.

Scientists at MIT have constructed a device by which the content of the vaccine is injected under the skin of the patient without the use of hypodermic needles. Simply put, it is a device that injects contents of vaccines by “jet" drive, without causing any pain. The advantage of this invention is that it can inject different amounts of vaccine at different depths.

Less Accidental Injuries

Scientists say the invention, along with many other benefits, can help prevent accidental injuries that occur daily handling with needles. U.S. Centers for Disease Control and Prevention estimates that hospital staff accidentally injures with needles of various vaccines even 385 000 times a year. Of course, in most cases it is only a tiny prick, but with this large number of accidental puncture there is a significant risk of transmission of certain serious diseases. From a multitude of other benefits should be noted that giving the vaccine without needles can significantly ease the life of people that have to be injected daily with medications such as insulin.

"If you have a fear of needles or must daily inject a drug, there is a good chance that you will sometimes avoid the prescribed treatment because of fear or discomfort," says Catherine Hogan, a scientist at MIT's Department of Mechanical Engineering and a member of the team that constructed this device. "We believe that this invention has an extraordinary potential in helping patients in overcoming phobias associated with medical needles," says Hogan.

Attempts To Replace The Needle

In the past few decades, scientists have tried various alternatives to hypodermic needles. Nicotine patches, for example, release slowly the drug, which then enters the body through the skin. But the problem with this solution is that from the patch only molecules that are sufficiently small may be released, as they have to be able to pass through tiny holes in the skin (pores). By replacing the hypodermic needle with patch, the range of drugs that patients can receive is therefore significantly limited.

More recently, in medicine are increasingly being used "big" drugs based on proteins that scientists had to find more efficient ways to bring in patients organisms. One of these methods is the injection of jet injection, that is able to inject painlessly various types of drugs at high speeds under the skin. Although in today's market there are several similar devices, Hogan points out that each of them has some significant drawbacks.

The Entry Under The Skin

MIT team led by Professor Ian Hunter, unlike all the previous cases, constructed the jet injection which was able to inject different doses of drugs at different depths and all this in a very reliable manner. The basis of the device is a mechanism called Lorentz-force actuator - a small but extremely strong magnet surrounded by a coil of wire that is connected to the piston within the ampule filled with medicine. When the current is released through the device, it activates a magnetic field which then generates a force that ejects the drug through the nozzle out under very high pressure and at very high speed (the speed of drug ejection is close to the speed of sound). The nozzle through which the drug is "fired out" is as wide as the proboscis by which mosquito stings their victims.

The speed of injection of the drug can be controlled by the amount of current that is passed through the device. The injection process is usually carried out in two phases. In the first stage (high pressure phase), the device ejects the drug under extremely high pressure. This is necessary in order to inject the drug under the skin and in order to reach the desired depth. In the second stage (low pressure phase) in which the pressure is significantly lower, the drug will be expelled in a slow stream to be absorbed by surrounding tissues properly.
When testing the device, the researchers noticed that the quantity and depth of drug injection significantly depends on the skin type on which the device is used.

"If, for example, using this device we wish to vaccinate a child, it would be much less pressure than when they tried to inject the drug under adult skin," says Hogan, and continues, "we can easily control the pressure at which the drug is injected, and that's one of the biggest advantages of this device. "