It’s fair to say that no-one likes receiving injections, yet for foreign travelers, children requiring immunizations, and flu shots, needles are an unfortunate necessity. However a team of scientists from Seoul National University in South Korea have developed a new laser-based system that blasts microscopic jets of drugs into the skin, negating the need for large and painful single-use hypodermic needles and the medical waste they entail. Best of all, the laser-jab is said to be no more painful than being hit with a puff of air.
The Star Trek-like system uses an erbium-doped yttrium aluminum garnet, or Er:YAG laser to propel a tiny, precise stream of medicine. The system was developed by Jack Yoh, professor of mechanical and aerospace engineering at Seoul National University in South Korea along with his graduate students. The team’s research was published in the Optical Society’s (OSA) journal Optics Letters.
The laser system is fitted with a small adaptor that contains the drug in liquid form. It also has a chamber containing water which acts as a “driving” fluid. A flexible membrane separates these two liquids until a laser pulse – which lasts just 250 millionths of a second – generates a vapor 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 meter (micrometers) in diameter – just a little larger than the width of a human hair.
“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,” Yoh said.
Due to the fine nature of jet, the medication can penetrate up to several millimeters beneath the skin surface, with no damage to the tissue and no pain to the patient. “Our aim is the epidermal layer,” Yoh added, which is located closer to the skin surface, at a depth of only about 500 micrometers. This region of the skin has no nerve endings, so the method “will be completely pain-free,” he says.
Yoh is now working with a company to produce low-cost replaceable injectors for clinical use. “In the immediate future, this technology could be most easily adapted to situations where small doses of drugs are injected at multiple sites,” he says. “Further work would be necessary to adapt it for scenarios like mass vaccine injections for children.”
Via BBC News
Images: Optics Letters and stevendepolo