View attachment 28184 Painful injections could eventually be a thing of the past, thanks to a breakthough by a team at Seoul National University in South Korea.
A new laser-based system that blasts microscopic jets of drugs into the skin is set to make jabs as painless as being hit with a puff of air.
Jack Yoh, professor of mechanical and aerospace engineering at the university, developed the device along with his graduate students.
The system uses an erbium-doped yttrium aluminum garnet, or Er:YAG, laser to propel a tiny, precise stream of medicine with just the right amount of force.
This type of laser is commonly used by dermatologists, particularly for facial aesthetic treatments, said Professor Yoh, who described the injector in a paper published in the Optical Society of America's journal Optics Letters.
The laser is combined with a small adapter that contains the drug to be delivered, in liquid form, plus a chamber containing water that acts as a "driving" fluid.
A flexible membrane separates these two liquids. Each laser pulse, which lasts just 250 millionths of a second, generates a vapour bubble inside the driving fluid.
The pressure of that bubble puts elastic strain on the membrane, causing the drug to be forcefully ejected from a miniature nozzle in a narrow jet a mere 150 millionths of a metre (micrometres) in diameter, just a little larger than the width of a human hair.
Professor Yoh said: "The impacting jet pressure is higher than the skin tensile strength and thus causes the jet to smoothly penetrate into the targeted depth underneath the skin, without any splashback of the drug."
Tests on Guinea pig skin show that the drug-laden jet can penetrate up to several millimetres beneath the skin surface, with no damage to the tissue.
Because of the narrowness and quickness of the jet, it should cause little or no pain, Professor Yoh said.
The team's aim is the epidermal layer, which is located closer to the skin surface, at a depth of only about 500 micrometres.
This region of the skin has no nerve endings, so the method will be completely pain-free, he insisted.
Although other research groups have developed similar injectors, they are mechanically driven, using piston-like devices to force drugs into the skin, which gives less control over the jet strength and the drug dosage.
"The laser-driven microjet injector can precisely control dose and the depth of drug penetration underneath the skin," the Professor added.
"Control via laser power is the major advancement over other devices."
Friday 14 September 2012, Sky News
No More Needles? Laser Breakthough Could Mean Pain-Free Injections