Laser-based Injection System Gives Painlesss Shots
Childhood immunization, annual flu vaccination and other injections make us constantly undergo uncomfortable pain sensation. Owing to a new laser-based system, developed by Jack Yoh, professor of mechanical and aerospace engineering at Seoul National University in South Korea, shots will be soon delivered painlessly. The adapted erbium-doped yttrium aluminum garnet (Er:YAG) laser is connected with a small adapter, which locates the liquid drug to be delivered, along with a chamber containing water, which acts as a “driving fluid”. The two liquids are kept apart by a flexible membrane and, as the laser is operated, each laser pulse generates a vapor bubble inside the driving fluid. This bubble in the water produces enough pressure to put an elastic strain on the membrane, causing the liquid drug to be pushed out of a miniature nozzle in a narrow jet, a bit larger than the a human hair, with just the right amount of force to break the skin. The jet pressure is higher than the skin tensile strength and thus causes the jet to smoothly penetrate into the needed depth underneath the skin. At present Yoh aims to produce low-cost, replaceable Er:YAG injectors for clinical use at multiple sites.