Needle-free jet injection system unveiled by MIT

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MIT researchers have engineered a device that delivers a tiny, high pressure jet of medicine through the skin without the use of a hypodermic needle. Unlike similar devices, the system can be programmed to deliver a range of doses to various depths and could help reduce the potential for needle stick injuries as well as patient anxiety.

The design is built around a mechanism called a Lorentz-force actuator - a small, powerful magnet surrounded by a coil of wire that's attached to a piston inside a drug ampoule. When current is applied, it interacts with the magnetic field to produce a force that pushes the piston forward, ejecting the drug at very high pressure and velocity (almost the speed of sound in air) out through the ampoule's ultra small nozzle. The speed of the coil and the velocity imparted to the drug can be controlled by the amount of current applied; the MIT team generated pressure profiles that modulate the current. According to the researchers, the resulting waveforms generally consist of two distinct phases: an initial high pressure phase in which the device ejects drug at a high enough velocity to 'breach' the skin and reach the desired depth, then a lower pressure phase where drug is delivered in a slower stream that can easily be absorbed by the surrounding tissue. Through testing, the group found that various skin types may require different waveforms to deliver adequate volumes of drugs to the desired depth. "If I'm breaching a baby's skin to deliver vaccine, I won't need as much pressure as I would need to breach my skin," said Catherine Hogan, a research scientist at MIT's Department of Mechanical Engineering. "We can tailor the pressure profile to be able to do that, and that's the beauty of this device." The team is also developing a version of the device for transdermal delivery of drugs ordinarily found in powdered form by programming the device to vibrate, turning powder into a fluidised form that can be delivered through the skin much like a liquid. Hunter says that such a powder delivery vehicle could be useful in developing countries where liquid vaccines need to be refrigerated. A vaccine that can be administered in powder form would require no cooling, according to Hogan, avoiding this problem.